Princess Margaret Cancer Centre Research Articles

Pivoting the Provision of Smoking Cessation Education in a Virtual Clinical World: The Princess Margaret Cancer Centre Experience.

Continued smoking after a cancer diagnosis may be attributed to misbeliefs by both patients and healthcare providers on the value and benefit of quitting smoking on treatment outcomes. The perceived myths and misconceptions about the relationship between smoking and cancer may be readily dispelled with the provision of practical and pertinent education. However, busy clinics as well as the rapid move to virtual care due to the COVID-19 pandemic present several challenges with the provision of smoking cessation education. Here, we describe how the Princess Margaret Cancer Centre implemented innovative solutions to improve the delivery of education during the COVID-19 pandemic to better support patients and healthcare providers.

Genomic characterization of non-schistosomiasis-related squamous cell carcinoma of the urinary bladder: A retrospective exploratory study.

BackgroundNon-schistosomiasis related-squamous cell carcinoma of urinary bladder (NSR-SCCUB) is a rare tumor subtype distinct from urothelial carcinoma (UC). Studies assessing molecular biomarkers in bladder cancer have generally focused on UC, and genomic data of NSR-SCCUB is limited. We aim to provide additional insight into the molecular underpinnings of this rare entity.MethodsNSR-SCCUB patients were identified retrospectively at Princess Margaret Cancer Centre between 2002 and 2017. Demographics, disease characteristics, therapeutic approaches, and outcomes were collected. Tissue samples were interrogated using the Oncomine Comprehensive Assay v3 (ThermoFisher). Kaplan-Meier method was used to estimate the disease-free survival and overall survival (OS).ResultsOverall, 11 patients with NSR-SCCUB were identified between 2002 and 2017 with adequate tissue samples. Median age was 71 years (45–86), predominantly male (63.6%). At time of diagnosis, 9 patients (81.8%) had muscle-invasive disease, 1 (9.1%) had non-muscle invasive, and 1 (9.1%) had advanced disease. Nine (81.8%) patients had radical cystectomy and pelvic lymph nodes dissection. Eight (72.7%) patients had pT3 or pT4 with N0, and 5 (45.5%) were grade 3. Median OS was 12.5 months (95% CI 7.7–17.2 months). Single nucleotide variants or insertion/deletions were identified in TP53, TERT, PIK3CA, PTEN, CREBBP, FBXW7, and FGFR3. Amplifications were found in CCND1, and EGFR.ConclusionsNSR-SCCUB has potentially actionable genomic alterations with anticancer agents and many of these aberrations are also seen in UC. The recruitment of NSR-SCCUB patients harboring such mutations should be considered in biomarker driven urinary bladder cancer studies.

Abstract LBA021: Immune resistance interrogation study (IRIS): Initial report of next generation sequencing (NGS) results in patients with primary versus acquired resistance to anti-PD1/L1 antibodies

Abstract Background: The molecular mechanisms underlying primary versus acquired resistance to anti-PD-1/L1 antibodies have not been comprehensively evaluated across different tumor types. Methods: The Immune Resistance Interrogation Study (IRIS; NCT04243720) is a prospective, investigator-initiated study at the Princess Margaret Cancer Centre, aimed to perform extensive multi-omic characterization of solid tumors with primary resistance (disease progression on first imaging; or stable disease <6 months) versus acquired resistance (partial or complete response; or stable disease ≥6 months) to antiPD-1/L1 agents. A one-time fresh tumor biopsy is collected from patients (pts) who have progressed on anti-PD1/L1 antibody-based treatment as their most recent line of therapy; liquid biopsy or archived FFPE tissue is allowed as alternates when fresh biopsy is insufficient. NGS was performed using Foundation One (324 genes) or Foundation Liquid (309 genes) panels. Frequencies of disrupted genes and variants were compared in pts with primary versus acquired resistance using Fisher’s exact test. The planned samples size of IRIS is 100 pts. Results: Among the first 35 pts enrolled, 22 (63%) had primary resistance and 13 (37%) had acquired resistance. The most common diagnosis was melanoma (17 pts; 49%); followed by head and neck squamous cell carcinoma (13 pts; 37%); endometrial cancer (2 pts; 6%); pleural mesothelioma, gastroesophageal junction and colorectal cancer (1 pt each; 3%). Foundation One was performed in 23 pts (66%), 22 of them (63%) had biopsies with sufficient quality for NGS, and 1 (3%) had the analysis performed using archival FFPE tissue. The remaining 12 pts (34%) had Foundation Liquid testing done using liquid biopsy. Thirty-three pts (94%) had at least one oncogenic alteration. Genes most frequently altered included: TP53 in 16 patients (46%), TERT promoter in 12 pts (34%), CDKN2A in 9 pts (26%), PIK3CA in 6 pts (17%), and PTEN in 5 pts (14%). At the variant level, the most frequent alterations were: TERT promoter -146C>T mutation in 6 patients (17%), followed by TERT promoter -124C>T mutation in 5 patients (14%), FGF19/FGF4/FGF3 and CCND1 amplifications in 4 pts each (11%), and MDM2 amplification, CDK4 amplification and CDKN2A loss, detected in 3 pts each (9%). Pts with acquired resistance had a higher frequency of TP53 mutations (9/13 = 69%) compared to primary resistance pts (7/22 = 32%), p=0.04; however this was not significant when corrected for multiple testing. Interestingly, amplifications in CDK4, CCND1, FGF 19/FGF 3/FGF 4, MDM2 and mutations in NF1 were only identified in pts with primary resistant tumors. Conclusions: No significant differences in disrupted genes and variants were observed in the current analysis. However, this can be due to the small number of pts analyzed thus far. Accrual to this study is ongoing. A comparison of alterations in oncogenic pathways is planned to further define the genomic landscape of pts with primary versus acquired resistance to anti-PD1/PDL1 blockade. Citation Format: Sofia Genta, Farnoosh Abbas Aghababazadeh, Ming S Tsao, Aaron R Hansen, Marcus O Butler, Albiruni R Razak, Philippe L Bedard, Ben X Wang, Pugh J Trevor, Sevan Hakgor, Jeffrey Woo, Benjamin Haibe-Kains, Lillian L Siu, Anna Spreafico. Immune resistance interrogation study (IRIS): Initial report of next generation sequencing (NGS) results in patients with primary versus acquired resistance to anti-PD1/L1 antibodies [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA021.

Abstract LBA013: Phosphoproteomics reveals active drug targets on pathways of resistance and predicts response to midostaurin plus chemotherapy in FLT3 mutant-positive acute myeloid leukemia

Abstract Background: Midostaurin (mido) is approved for treatment of FLT3 mutant-positive (FLT3+) acute myeloid leukemia (AML). However, FLT3 mutation is not the only determinant of mido sensitivity. Here we report phosphoprotein signatures which predict response to chemotherapy (chemo) plus mido, and identify active drug targets on potential resistance pathways. Methods: Samples collected at diagnosis, post-treatment and relapse from FLT3+ patients treated with chemo+mido were obtained from the Leukemia Tissue Bank at the Princess Margaret Cancer Centre. Peptides and enriched phosphopeptides from bone marrow (BM) and peripheral blood (PB) mononuclear cells were quantified using liquid chromatography-tandem mass spectrometry. Signatures for BM/PB diagnosis samples were analyzed independently and used to train a classification machine learning algorithm to group patients (n=54) based on response to treatment. Additional features (e.g. genetic mutations) were also analyzed. Kaplan-Meier and Log-Rank test methods were used to assess differential survival between patient groups. To investigate pathways potentially driving resistance to chemo+mido, differential protein phosphorylation indexes were identified through comparison of post-treatment or relapse samples to paired diagnosis samples. To account for population heterogeneity, a filter was applied based on frequency of observation. Activated pathways potentially driving resistance were identified with functional enrichment tools and kinase-substrate enrichment analysis. Statistical significance of enrichment were determined using parametric methods and p-values adjusted for multiple testing using the Benjamini-Hochberg method. Results: Patients positive for a signature consisting of 26 phosphorylation sites showed a markedly longer survival time than negative patients (PB: 269 vs 76 weeks, Log-Rank p=1.30e-05; BM: 241 vs 56, Log-Rank p=2.13e-09). This signature partially overlapped with an ex-vivo signature of response to mido, described previously by Casado et al (Leukemia, 2018). A proteomic signature was also identified, with positive patients showing a longer survival time than negative patients (PB: 330 vs 173 weeks, Log-Rank p=5.0e-04; BM: 460 vs 156, Log-Rank p=5.2e-06). Key, diverging phosphorylation site signatures were identified between patients with refractory disease/early relapse and patients with complete response and no relapse or death within 2 years post-treatment. Pathways with increased activity in post-treatment or relapse specimens were associated with molecular functions such as regulation of cell proliferation, migration, differentiation and anti-apoptosis. Conclusions: We identified phosphoproteomic and proteomic signatures that differentiate survival mediated by response to chemo+mido. While the former was more predictive, both may enable further stratification of FLT3+ AML receiving mido treatment. Drug targets on pathways demonstrating increased activity in relapse/refractory cases may play a role in resistance; this will be determined in follow-up inhibitor studies. Citation Format: Luis Veiga Nobre, Celia Colomina Basanta, Salvatore Federico Pedicona, Arran David Dokal, Andrea Arruda, Ryan Smith, Calum Greenhalgh, Francesca Patella, Pedro Maria Casado-Izquierdo, Bela Wrench, Jane Theaker, Andrew Thompson, Mark D. Minden, John G. Gribben, David James Britton, Pedro Rodriguez Cutillas. Phosphoproteomics reveals active drug targets on pathways of resistance and predicts response to midostaurin plus chemotherapy in FLT3 mutant-positive acute myeloid leukemia [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA013.

Editorial Comment.

No AccessJournal of UrologyAdult Urology1 Feb 2022Editorial CommentThis article comments on the following:An Algorithm to Personalize Nerve Sparing in Men with Unilateral High-Risk Prostate Cancer Nathan Perlis Nathan PerlisNathan Perlis Urologic Oncology, Princess Margaret Cancer Centre, Sprott Department of Surgery, University Health Network, University of Toronto, Toronto, Ontario, Canada More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002205.01AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "Editorial Comment." The Journal of Urology, 207(2), p. 357 Reference 1. : Multifocality and prostate cancer detection by multiparametric magnetic resonance imaging: correlation with whole-mount histopathology. Eur Urol 2015; 67: 569. Google Scholar © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetailsRelated articlesJournal of UrologySep 22, 2021, 12:00:00 AMAn Algorithm to Personalize Nerve Sparing in Men with Unilateral High-Risk Prostate Cancer Volume 207Issue 2February 2022Page: 357-357 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nathan Perlis Urologic Oncology, Princess Margaret Cancer Centre, Sprott Department of Surgery, University Health Network, University of Toronto, Toronto, Ontario, Canada More articles by this author Expand All Advertisement PDF DownloadLoading ...

Abstract 10797: Applying Cardiotoxicity Risk Prediction Scores in Women with Early-Stage Breast

Background: Cardiotoxicity is a common complication of anthracyclines and HER2-targeted therapies in breast cancer patients. Despite recognized risk factors, accurate prediction of cardiotoxicity risk remains a challenge. We applied 3 published risk prediction scores (Table) to a cohort of women with HER2+ breast cancer treated with anthracycline and trastuzumab and described their predictive accuracy. Methods: Women with stage I-III HER2+ breast cancer treated at the Princess Margaret Cancer Centre (Toronto) between 2006-2019 were identified retrospectively. Those with a pre-therapy MUGA scan or 2D echocardiography and ≥ 3 follow up scans using the same modality were included. CREC criteria were applied to define cardiotoxicity. Three risk prediction scores (Ezaz et al., Romond et al., and HFA-ICOS proformas) were used to classify patients into low/medium/high cardiotoxicity risk according to pretreatment characteristics. The proportion of patients who developed cardiotoxicity across risk categories were compared within each score using chi-square test. Results: Of 629 women (mean age 52.4 ± 10.9 years), 151 (24%) met CREC cardiotoxicity criteria. With the Ezaz et al. score , proportion of patients that developed cardiotoxicity was 24.4% (n = 141/577), 20% (n = 9/45) and 14.3% (n =1/7), in the low, medium, and high predicted risk groups, respectively (p = 0.665). With Romond et al. score , this was 17.9% (n = 40/223), 24.5% (n = 50/204) and 30.5% (n = 61/200), respectively (p = 0.01). HFA-ICOS was 15.5% (n = 30/193), 26.9% (n = 109/404), and 37.5% (n = 12/32), respectively (p = 0.002). Conclusion: In women with early stage HER2+ breast cancer receiving trastuzumab therapy, risk scores by Romond et al., and the HFA-ICOS proformas predict cardiotoxicity risk. However, for both these scores the incidence of cardiotoxicity in the “low” predicted risk group remains high (15.5%-17.9%). Therefore, there remains a need to develop more accurate risk prediction scores.

Management of stage I testicular cancer.

Testicular cancer is the most common solid malignancy amongst young men, and a large proportion present with stage I disease. The options for management following radical orchiectomy are multifold. We review here approaches to treatment in this setting, providing an update on recent publications. At Princess Margaret Cancer Centre, we maintain a nonrisk adapted active surveillance approach. With a dedicated surveillance program using low-dose computed tomography imaging, patients are appropriately identified early for treatment on relapse. There are ongoing investigations into minimizing toxicities of treatments for relapse, and in particular, retroperitoneal lymph node dissection (RPLND) presents an attractive alternative. This, though, remains investigational in the setting of seminoma. Testicular cancer is a highly curable malignancy. In stage I disease, an active surveillance approach following radical orchiectomy is preferred, irrespective of risk-profile. This approach serves to limit the toxicity of adjuvant treatment in a significant proportion of patients, while maintaining excellent survival outcomes.

Virtual Care during the COVID-19 Pandemic Among Patients with Hematologic Malignancies - a Princess Margaret Cancer Centre Experience

Background:The use of virtual care rapidly increased during the COVID-19 pandemic to provide adequate care for patients while minimizing contact. Studies in solid tumors show high rates of patient satisfaction with virtual care as well as cost-savings. However, little is known about the application of virtual care in malignant hematology, which includes a heterogenous population of patients often at increased risk of infection. Understanding when virtual care or a hybrid model can be used is crucial for comprehensive patient care.Methods:A retrospective review of patients with hematologic malignancies receiving care at Princess Margaret (PM) Cancer Centre in Toronto, Canada from October 2019 to March 2021 was performed. The primary objective was to describe the use of virtual care at three time points: prior to the pandemic, during the initial months of the pandemic, and beyond the initial months. Patients were included in the analysis if they had a clinical visit for their hematologic malignancy. Patients were excluded if they were presenting for treatment-related visits or blood count checks. All methods of virtual care, including phone visits and teleconferencing, were included in the analysis. Patient satisfaction with virtual care was assessed using responses to the Your Voice Matters survey administered from September 2020 to April 2021, a provincial survey of patient-reported experience.Results:A total of 93472 visits for 23162 patients were identified at PM from October 2019 to March 2021 (55% of visits for ambulatory clinic appointments). Mean age was 60 years (range 18-103 years) and 45% of patients were female (N = 23162). Ambulatory clinic appointments for new consultation or follow-up care were done in the following clinics: autologous or allogeneic bone marrow transplant (21%, N = 10 747), cellular therapy (0.2%, N = 82), leukemia (26%, N = 13419), lymphoma (32%, N = 16427) and myeloma (21%, N = 10711).From October 2019 to March 2020, there were 14512 visits, of which nearly 100% were in-person (N = 14511). From March 1 2020 to September 1 2020, there were 19179 total visits, of which 36% were virtual, with the majority of visits by phone (6325 phone visits and 567 video visits). From September 1 2020 to March 1 2021, there was a small decrease in the use of virtual care (p<0.01), but utilization of phone and video visits continued to be used for 30% of patients (N=17695 total visits; 4964 phone visits and 327 video visits). Virtual care was most often used for patients with myeloma (46%) or lymphoma (36%), as shown in Figure 1.A total of 75 survey responses for patients with hematologic malignancies followed at PM were available. 67 responses (89.3%) were from patients, with the remaining from caregivers. 47 visits (62.7%) were in-person, 26 visits (34.7%) were virtual, and 2 visits (2.7%) did not have the visit type available. Survey results are shown in Table 1. Results for in-person and virtual visits were very similar, with both groups reporting that their provider listened to their concerns and involved them in making treatment decisions. There was a trend toward providers discussing physical symptoms more for patients who had virtual visits (mean score of 4.73/5 for virtual visit compared to a mean score of 4.36/5, p=0.10). Data on next visit type preference was available for 25 patients who had a virtual visit and 46 patients who had an in-person visit. For patients who had a virtual visit, 36% preferred a repeat virtual visit with 56% having no preference and only 7.7% preferring an in-person visit. For patients who had an in-person visit, 33% preferred their next visit to be virtual, with only 24% preferring their next visit to be in-person and the remaining 43% having no preference.Conclusion:The use of virtual care increased substantially during the COVID-19 pandemic and persisted into 2021 with high rates of patient and provider satisfaction. The highest uptake of virtual care was for patients with myeloma or lymphoma. There were no significant differences in patient satisfaction scores for virtual visits compared to in-person visits, and one third of patients preferred a virtual visit after an in-person visit. These findings suggest that virtual care is a feasible and preferred tool for delivering care to a substantial proportion of patients with hematologic malignancies. Further work is needed to determine how to optimally integrate virtual care for specific patient populations. [Display omitted] DisclosuresPrica: Astra-Zeneca: Honoraria; Kite Gilead: Honoraria.

A Phase 2 Open-Label, Multicenter, Dose Optimization Clinical Study of the Safety, Tolerability, and Pharmacokinetic (PK) and Pharmacodynamic (PD) Profiles of Cfi-400945 As a Single Agent or in Combination with Azacitidine or Decitabine in Patients with Acute Myeloid Leukemia, Myelodysplastic Syndrome or Chronic Myelomonocytic Leukemia (TWT-202)

Background: CFI-400945 is a potent, selective, orally administered, first-in-class inhibitor of the serine/threonine kinase, Polo-like kinase 4 (PLK4). PLK4 is a highly conserved master upstream regulator of centriole duplication and is critical for maintenance of genomic integrity. Aberrant expression of PLK4 results in a number of effects including the centrosome amplification often seen in aneuploid cancers, pointing to a potentially causative role for PLK4 in genome instability and cancer progression. A Phase 1 study has been completed evaluating CFI-400945 as a monotherapy in solid tumors, showing a tolerable safety profile and promising signs of activity. Given acute myeloid leukemia (AML) is characterized by genomic instability, CFI-400945 has been evaluated in pre-clinical and clinical studies in AML. In pre-clinical studies, CFI-400945 showed potent activity towards leukemia cell lines and primary human samples in vitro, as well as marked efficacy in two subcutaneous models of leukemia. A prior Phase 1 trial in AML was initiated at the Princess Margaret Cancer Center (PMCC), and of six patients evaluable for response, two (33%) achieved complete remission (CR) at 96 mg and 128 mg, and 3 patients (50%) had stable disease (with one patient having a 78% reduction in marrow blast count) at 64 mg (2 patients) and 96 mg [re: Murphy et al, ASH 2020]. Responses were seen in patients with adverse cytogenetics. The optimal dosing of CFI-400945 and its potential role as a combination agent are not yet clinically defined.Study Design and Methods: The study (TWT-202) has 4 parts, Part 1A (1A): a single agent dose escalation portion, Part 1B (1B): a food effect portion once the MTD of 1A is determined, and combinations with azacitidine (2A), and decitabine (2B). TWT-202 uses an updated version of investigational product which is identical in formulation to the drug used in the PMCC study, but which may result in higher exposures at a given dose. This study will therefore refine the dose through escalation cohorts. For parts 1A and 1B, patients with relapsed and/or refractory AML, MDS, or CMML after >1 prior therapy will be included. Patients with MDS or CMML must have progressed or had a lack of response after at least 4 cycles of hypomethylating agents. For parts 2A and 2B, patients should have relapsed and/or refractory AML or untreated MDS or CMML. Untreated patients who decline or are ineligible for intensive therapy may be included. The study will use a standard 3 + 3 design. The maximum tolerated dose (MTD) will be defined as the dose level where the number of dose limiting toxicities (DLTs) is <1 out of 6 at highest dose level below the maximally administered dose. Pharmacokinetics (PK) and pharmacodynamic (PD) markers will be assessed.Results: As of June 21, 2021, 2 patients had been enrolled into the study, one of the patients (50%) received >3 prior therapies (including venetoclax). Neither patient had had stem cell transplant at study entry. Both patients had secondary AML (one with antecedent MDS with excess blasts and the other with CMML). Both patients received 32 mg of CFI-400945 for 21 days followed by a 7-day rest. Both patients completed cycle 1 and neither experienced a DLT. Both patients experienced a single serious treatment emergent adverse event (SAE) of febrile neutropenia each, with neither event considered related to CFI-400945. There were 13 Grade 3 or greater TEAE's, including anemia, thrombocytopenia (3 events each), febrile neutropenia (2 events), agitation, angioinvasive fungal sinusitis, acute kidney injury, hypotension and neutropenia (1 event each). None of the grade 3 or greater TEAE's were considered related to CFI-400945. Neither patient responded to therapy at 32 mg and both came off treatment after one cycle due to progressive disease. PK and PD studies are pending.Conclusion: CFI-400945 has been generally well tolerated and TWT-202 continues to enroll in the Part 1A and Part 1B monotherapy cohorts. Updated safety, efficacy, PK, and PD data for the study will be presented at the time of the meeting. DisclosuresBorthakur: University of Texas MD Anderson Cancer Center: Current Employment; ArgenX: Membership on an entity's Board of Directors or advisory committees; Protagonist: Consultancy; Astex: Research Funding; Ryvu: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees. Jonas: 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie: Other: Travel reimbursement; AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy. Roberts-Thomson: Treadwell Therapeutics: Current Employment. Michelson: Treadwell Therapeutics: Consultancy. Bray: Treadwell Therapeutics: Current Employment.

Pregnancy Management and Outcomes in Patients with Myeloproliferative Neoplasms

▪Introduction:While BCR-ABL1 negative myeloproliferative neoplasms (MPN) are typically diagnosed in the sixth decade of life, approximately 20% of patients are diagnosed before the age of 40 years. Patients with MPN of reproductive age are being increasingly encountered in clinical practice. Concurrently, there has been increased awareness of the risks of pregnancy complications in patients with MPN and the importance of MPN-specific management to help mitigate these risks. MPN are associated with thrombotic and hemorrhagic complications, and pregnancy may amplify the thrombotic risk. Additionally, MPN may be associated with an increased risk of placental dysfunction and associated complications of preeclampsia, fetal growth restriction, preterm delivery and fetal loss. The aim of this observational study was to report on pregnancy outcomes in a modern cohort of patients with MPN managed according to consensus recommendations.Methods:We conducted a retrospective review of patients with MPN and pregnancy evaluated at either the Princess Margaret Cancer Centre or Mount Sinai Hospital in Toronto, Canada between January 1, 2010 and December 31, 2020. Diagnoses were defined according to the WHO 2016 criteria using information available from hospital records. Descriptive statistics were used to describe selected baseline characteristics. Categorical variables were summarized with counts and percentages.Results:A total of 32 patients with MPN and pregnancy were included in the study (Table 1). The median age at the time of the index pregnancy was 33 (range 21 - 45) years. The most common MPN diagnosis was essential thrombocythemia (ET, n=15), followed by polycythemia vera (PV, n=9) and primary myelofibrosis (PMF, n=8). Driver mutation data was available for 30 patients: 17 (57%) had mutated JAK2, 5 (17%) CALR, and 9 (30%) had no driver mutation identified. Five patients had a prior history of venous thrombosis, all of which were portal vein thrombosis, and 2 patients had a history of bleeding events. Information on antenatal treatment was available for 22 patients: 18 (82%) patients received aspirin, 3 (14%) received antenatal low molecular weight heparin (LMWH) and 3 (14%) received interferon (IFN; interferon alpha 2b in 2 cases and pegylated interferon alfa 2a in 1); 16 (73%) received post-partum LMWH.Information on maternal complications was available for 22 patients. There were 2 thrombotic events (1 antepartum and 1 postpartum) and 1 postpartum hemorrhage. There were no cases of preeclampsia. Of 22 pregnancies, there were 19 live births (86%), 2 first trimester losses (9%) and 1 second trimester loss (5%). Gestational age was 37 weeks or more in 16/17 (94%) and was 33 weeks for 1 patient. Vaginal deliveries were performed in 11/20 (55%) cases and 9/20 (45%) were Cesarean deliveries.Discussion:This observational study represents a modern cohort of MPN patients treated according to consensus recommendations. Our findings highlight that MPN patients have better pregnancy outcomes than those previously described in the literature. Limitations of this retrospective study include a small sample, missing data, and potential underreporting of early pregnancy loss. Pregnancy in patients with MPN is associated with unique risks that may be reduced with interventions such as antepartum aspirin, IFN in higher risk patients, and postpartum LMWH. That not all standard risk patients were managed with aspirin and postpartum LMWH suggests educational opportunities exist for hematologists and maternal-fetal medicine physicians involved in the care of these patients. [Display omitted] DisclosuresGupta: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Pfizer: Consultancy; Roche: Consultancy; Constellation Pharma: Consultancy, Honoraria; Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Research Funding. Malinowski: Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy. Maze: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Honoraria; Takeda: Research Funding; PharmaEssentia: Research Funding; Kronos Bio: Research Funding.

ATG and Post-Transplant Cyclophosphamide Predisposes to Inferior Outcome When Using Cryopreserved Stem Cell Grafts

BackgroundDuring 2020, the novel COVID-19 pandemic lead to cryopreservation of allogeneic hematopoietic stem cell (HSCT) grafts based on NMDP and EBMT recommendations, to secure grafts before start of conditioning chemotherapy. We examined the impact of this change in practice on patient outcomes.MethodsWe retrospectively analyzed the outcomes of 483 patients who received HSCT between Aug 2017 and Aug 2020, at Princess Margaret Cancer Centre, Canada, comparing the outcomes between those who received cryopreserved (CRYO, n=135) or fresh peripheral blood stem cell grafts (FRESH, n=348). Median follow-up: 12.3 months.Probability of overall survival (OS) was calculated using the Kaplan-Meier product-limit method and heterogeneity of time-to-event distribution functions were compared by the log-rank test. Cumulative incidences of aGvHD and cGvHD, relapse, and non-relapse mortality (NRM) were estimated using the cumulative incidence method considering competing risk, and groups were compared using Gray's test. Death was considered as a competing event for relapse, aGvHD and cGvHD, and relapse was considered a competing event for NRM, aGvHD and cGvHD.ResultsMedian age was 58y; 54.5% were males. Acute myeloid leukemia was commonest HSCT indication (n=248, 49.1%). Donors: MUD 10/10 n=233; MUD 9/10 (MMUD) n=48, matched related donor (MRD) n=112, Haploidentical n=88. Transplant conditioning: 79 (23%) and 23 (17%) patients received myeloablative conditioning (MAC) in the FRESH and the CRYO groups, respectively (p ns). In the FRESH group, 253 (73%) patients and 114 (84%) patients in the CRYO group received ATG followed by posttransplant cyclophosphamide (PTCy) and Cylosporine GvHD prophylaxis.OS at the 2y timepoint, FRESH group (n=348), was 67.0% (61.1-72.3%), compared to 48.7% (38.1-58.4%) for patients in the CRYO group (n=135), p=0.002, Figure 1a. This was mainly due to MRD cohort outcomes: 2y OS in MRD FRESH group (n=65), was 85.2% (73.3-92.0%), compared to 45.1% (29.9-59.1%) in MRD CRYO group (n=47), p<0.001, Figure 2a. Multivariate analysis (MVA) for OS, significant factors were increasing patient age, DRI high/v.-high, HCT-CI ≥ 3, Donors: Haplo and MMUD, cryopreservation, Table 1.NRM at 1y for FRESH (n=348) 17% (13.2-21.2) vs CRYO (n=135) 22.1 % (14.8-30.4), p ns . However, in the MRD cohort, NRM at 1y for FRESH group (n=65), was 1.5% (0.1-7.4%), compared to 15.4% (6.6-27.4%) for CRYO group (n=47), p=0.003, Figure 2b . On MVA, NRM adverse significant factors were patient age, DRI high/v.-high, Donors: Haplo and MMUD, Table 1.Cumulative incidence (CI) of relapse at 2y for FRESH 22.4% (17.5-27.7) vs CRYO 27.0 % (18.8-35.9) p=0.07 .The CI of moderate-severe cGvHD at 1y for FRESH group (n=315) was 21.5% and 10.8% in the CRYO group, p=0.027, Figure 1c . Patients with FRESH 10/10 MUDs (n=180), had CI of moderate-severe cGvHD at 1y of 20.6%, compared to CRYO 10/10 MUDs (n=35), 6.0% p ns for MUDs; FRESH MRD (n=64) CI was 30.1%; and CRYO MRD (n=43) 10.3%, p=0.008 for MRD, Figure 1d. On MVA, significant adverse factors for chronic GvHD were increasing donor age, male recipient/female donor, whilst graft CRYO was protective, Table 1.GvHD-and Relapse free Survival (GRFS) at 2y for FRESH 54.0% (47.9-59.6) vs CRYO 43.4% (33.4-53.0) p<0.05, Figure 1b. However, in the MRD cohort, GRFS at 2y in FRESH group (n=65), was 74.2% (61.3-83.4%), compared to 40.7% (26.3-54.6%) for CRYO group (n=47), p=0.001; other donor types no difference, Figure 1c. On MVA, significant factors correlated with worse GRFS were: DRI high and very-high, cryopreservation, Donors: Haplo and MMUD, Table 1.Compared to FRESH group, CRYO group experienced reduced cGvHD, delay in neutrophil engraftment, higher graft failure and increased CMV reactivation, with no difference in relapse incidence or acute GvHD.ConclusionCryopreservation was associated with inferior outcomes post-HSCT particularly in the MRD cohort, possibly due to combination ATG and post-transplant cyclophosphamide impacting differential tolerance to cryopreservation on components of the stem cell graft; further studies are warranted to elucidate mechanisms for this observation. [Display omitted] DisclosuresLaw: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Kim: Bristol-Meier Squibb: Research Funding; Paladin: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company.

Proteomics and Phospho-Proteomics Reveal Predictive Signatures of Response and Mechanisms of Resistance to Midostaurin Plus Chemotherapy in FLT3 Mutant Positive Acute Myeloid Leukemia

Background: Midostaurin is approved for FLT3 mutant-positive (FLT3+) acute myeloid leukemia (AML), however efficacy has also been observed in a subpopulation of FLT3 mutant-negative AML, suggesting that FLT3 mutation is not the only determinant conferring midostaurin sensitivity.Casado et al previously described phosphoprotein signatures significantly associated with ex vivo responses to midostaurin in primary AML blasts (Casado et al Leukaemia 2018). In the current study, we tested whether our signatures could group FLT3+ patients based on clinical responses to midostaurin plus chemotherapy.Methods: FLT3+ bone marrow (BM) and peripheral blood (PB) specimens were collected at diagnosis, post-treatment and relapse (n=54 cases) from the Leukemia Tissue Bank at Princess Margaret Cancer Centre. All patients in this study were treated with standard chemotherapy plus midostaurin. Protein/phosphoprotein-signatures for BM and PB samples were analysed independently. Case-studies with multiple post-treatment time-points or relapse events following second line treatments were also analysed.Peptides (proteomics) and enriched phosphopeptides (phosphoproteomics) were quantified using liquid chromatography - tandem mass spectrometry. A classification machine learning (ML) algorithm was trained to group patients based on response to treatment as a function of protein/phosphoprotein-signature status. Other features (e.g. genetic mutations, HSC-transplant) were also analysed. Differential survival analysis between patient groups was carried out with Kaplan-Meier and Log Rank test methods.Pathways upregulated in post-treatment or relapse specimens, particularly from those cases that responded poorly to chemo + midostaurin (i.e. early relapse / refractory disease) were investigated using enrichment statistical methods including kinase-substrate enrichment analysis (KSEA) and gene ontology analysis and identified as potential mechanisms of resistance. Statistical significance of enrichment was determined using parametric methods and p-values adjusted for multiple testing using the Benjamini-Hochberg method.Results: ML models were developed based on the ex-vivo phosphoproteomics signatures described in the Casado et al study, from which we trained a predictive model (model 1). Patients positive for model 1 exhibited a survival probability of 243 weeks, compared to 126 weeks in signature negative patients (averages by geometric mean, Log Rank p = 9.88e-05).As the patients in the current study received chemotherapy, in addition to midostaurin, we identified a new phosphoproteomic signature consisting of 26 phospho-sites which partially overlapped with the ex-vivo signature. Patients positive for this new phosphoproteomic signature showed a markedly longer survival time than negative patients (269 vs 76 weeks, Log Rank p = 1.30e-05 for PB and 241 vs 56, Log Rank p = 2.13e-09 for BM specimens, Table).A proteomic signature was also identified in the current study. Positive patients showed a longer survival time than negative patients (330 vs 173 weeks, Log Rank p = 5.0e-04 for PB and 460 vs 156, Log Rank p = 5.2e-06 for BM specimens, Table), however this was less differentiating than the phosphoproteomic signature.Pathways upregulated in post-treatment or relapse specimens from early relapse or refractory cases were associated with molecular functions such as cell proliferation, anti-apoptosis, non-homologous end-joining, transcriptional regulation, spliceosome and cytoskeleton remodelling.Conclusions: We have identified protein and phosphoprotein signatures with the potential to further stratify AML for midostaurin treatment. Phosphoproteomic signatures differentiated according to response better than the proteomic signatures. Pathways upregulated in relapse/refractory cases may have a role in resistance and this will be determined in follow up studies. Analysis will also be performed on FLT3 mutant-negative cases to validate the signatures and elucidate mechanisms of resistance in this group. DisclosuresVeiga Nobre: Kinomica Ltd.: Current Employment. Minden: Astellas: Consultancy. Gribben: Janssen: Honoraria, Research Funding; AZ: Honoraria, Research Funding; Abbvie: Honoraria; BMS: Honoraria; Gilead/Kite: Honoraria; Morphosys: Honoraria; Novartis: Honoraria; Takeda: Honoraria; TG Therapeutics: Honoraria. Britton: Kinomica Ltd.: Current Employment, Current equity holder in publicly-traded company.

Clinical Features and Long-Term Outcomes in a Molecularly-Annotated Cohort of Adolescents and Young Adults with Myeloproliferative Neoplasms

▪Background:Myeloproliferative neoplasms (MPNs) are a heterogenous group of chronic hematologic malignancies that lead to morbidity and early mortality primarily due to thrombotic complications and progression to acute leukemia. Clinical and mutational risk factors have been demonstrated to predict outcomes in patients with MPNs, and are used commonly to guide therapeutic decisions (including allogenic stem cell transplant) in myelofibrosis. Adolescents and young adults (AYA, age ≤45 years) comprise less than 10% of all MPN patients, and have unique clinical and therapeutic considerations. The prevalence and clinical impact of somatic mutations implicated in myeloid disease has not been extensively reported in this population.Methods:We conducted a retrospective review of patients evaluated at the Princess Margaret Cancer Centre (PMCC) between 1/1/2000 and 30/6/2021 for an MPN diagnosed at ≤45 years of age. Diagnoses were defined per 2016 WHO criteria using available information on chart review. Targeted mutational profiling of clinically relevant myeloid genes (49- or 54-gene panel) was previously performed on peripheral blood or bone marrow samples. Pathologic variants in ASXL1, EZH2, IDH1/2, SRSF2, and U2AF1 Q157 were categorized as high-molecular risk (HMR). Categorical variables were compared using the χ2 test. Kaplan-Meier method was used for overall survival (OS) and time-to-event analysis; and were compared using the log-rank test.Results:A total of 237 patients with initial MPN diagnosis ≤45 years were included in the study, with median age of diagnosis 35 (range 12-45) years. MPN diagnosis included: essential thrombocythemia (ET, n=100), polycythemia vera (PV, n=75), prefibrotic primary myelofibrosis (Pre-PMF, N=29), overt PMF (n=24), and MPN-unclassifiable (MPN-u, n=9). Driver mutation data, available for 230 (97%) patients, were: JAK2 in 134 (56%), CALR in 70 (30%), MPL in 6 (2.5%), and triple-negative in 20 (8.4%) patients.Median follow-up was 10.2 (range 0.3-45.3) years, and median OS was the shortest for those with overt PMF (21.4 years, P=0.001) compared with PV (33.0 years), ET (31.4 years), and Pre-PMF (median OS not reached). No difference in OS based on driver mutation was observed. Progression to a secondary MF (SMF) was observed in 84 patients (47% of ET, 48% of PV) after median time of 19.7 years; with no difference in time to progression due to diagnosis or driver mutation. Progression to an accelerated/blast phase (AP/BP) was observed in 26 patients and was associated with diagnosis of overt PMF (P=0.04) and triple-negative for driver mutation (P=0.04).Thrombosis was observed in 61 (26%) patients: 34 (14%) patients with thrombosis prior to/concurrent with MPN diagnosis, and 34 (14%) patients with thrombosis after diagnosis. Splanchnic circulation thrombosis was found in 29 (12%) patients and 12 (5%) patients had Budd-Chiari syndrome. Portal hypertension was reported in 37 (16%) patients. CALR type-2 mutations were associated with the lowest frequency of total thrombosis (4%, P=0.02); while JAK2 had the greatest frequency of splanchnic circulation clot (17%, P=0.03).Targeted mutational profile was obtained for 202 (85%) of patients: 135 samples obtained during the initial disease phase, 51 samples during a secondary MF phase, and 16 during an AP/BP. For the patients with mutation analysis in the initial phase, 24 pathogenic mutations were observed in 16 (12%) patients including 3 patients with HMR mutations. The most frequent mutations observed were in TET2 (n=12, 9%), and ASXL1 (n=3, 2%). Presence of additional mutations did not predict OS, AP/BP progression, or thrombosis; though TET2 mutation was associated with shorter time to SMF progression in patients with PV/ET (P=0.002). Additional mutations were found in 34/51 (67%) patients in whom mutational analysis was first performed during a SMF disease phase.Conclusions:A long-term follow-up study of a large molecularly annotated cohort of AYA patients with MPN demonstrated excellent long-term survival for these patients. Overt PMF is associated with the lower OS and higher risk of AP/BP transformation. Thrombotic complications including splanchnic circulation thrombosis are frequent complications. Mutations aside from JAK2/MPL/CALR are uncommon and HMR mutations rare in the initial phase of MPN in the AYA population. [Display omitted] DisclosuresGupta: Roche: Consultancy; Pfizer: Consultancy; AbbVie: Consultancy, Honoraria; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Research Funding; Constellation Pharma: Consultancy, Honoraria. Maze: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Honoraria; Takeda: Research Funding; PharmaEssentia: Research Funding; Kronos Bio: Research Funding.

Progressive Multifocal Leukoencephalopathy in Multiple Myeloma: A Single Institution Case Series

IntroductionProgressive multifocal leukoencephalopathy (PML), caused by the John Cunningham (JC) virus, is an infection that requires immunosuppression for its manifestations and is fatal disease in many cases. (1) After asymptomatic primary infection, which occurs in childhood, the virus remains quiescent. (1,4) The classical clinical presentation is that of a subacute symptomatology that develops over weeks or months and consists of diverse sensorimotor abnormalities depending on the site of brain involvement. Approximately 22 cases of PML amongst patients with multiple myeloma (MM) have been reported in the literature between 1965 and April 2020. (5)MethodsWe performed a retrospective chart review of all myeloma patients who were treated at the Princess Margaret Cancer Center from 2010-2020 to identify cases of PML. Patient and disease characteristics, responses, and survival outcomes were collected from Myeloma and Stem Cell Transplant databases and electronic patient records under REB approval.ResultsWe identified 3 cases of PML in MM patients at our center over the past 10 years, all of which occurred in patients receiving therapy containing an immunomodulatory derivative (IMID), i.e., thalidomide, lenalidomide or pomalidomide.Patient 1A 52-year-old male with kappa light chain MM presented in 2009 on hemodialysis and received upfront bortezomib and dexamethasone followed by melphalan 200mg/m 2 and autologous stem cell transplantation (ASCT) in March 2010; maintenance with thalidomide was given until July 2011 when he presented to the ER with left-sided weakness, facial droop, and decreased strength. CT scan showed right-sided hypodensity in keeping with demyelination. PML was confirmed by MRI, lumbar puncture with positive PCR for JC virus, and a brain biopsy (Fig 1 A-C). He was treated with mirtazapine, and also developed status epilepticus controlled with phenytoin and phenobarbital. His myeloma treatment was never resumed after the diagnosis of PML due to concerns about viral reactivation. Approximately 3 years after PML diagnosis, his serum free kappa protein levels started to increase; he remained on hemodialysis but experienced no new myeloma-related organ damage and no myeloma treatment was offered. His last follow-up in clinic was in March 2019. However, he succumbed to S. pneumonia septicemia in July 2019.Case 2A 68-year-old female with IgG kappa MM diagnosed in 2004 was treated with high-dose dexamethasone induction followed by melphalan 200mg/m 2 and ASCT and relapsed 2 years later. She commenced cyclophosphamide and prednisone until July 2011 when treatment was changed to lenalidomide and prednisone; subsequent progression in February 2014 was treated with pomalidomide/bortezomib/prednisone. In November 2014, we noticed worsening vision. Brain MRI showed hyperintensity in T2 in the occipital lobe. Her myeloma treatment was stopped and she received corticosteroids with no improvement. LP in January 2015 was positive for JC virus and the diagnosis of PML was made. She was managed with supportive measures. Her last clinic follow-up was in 2015 and the patient died from progression in September 2015.Case 3A 52-year-old male with IgA lambda MM diagnosed in 2015 was treated with CYBOR-D induction followed by melphalan 200mg/m 2 and ASCT. He initially received lenalidomide maintenance which was changed to bortezomib due to toxicity. On progression in January of 2019 he was placed on a clinical trial of the anti-BCMA antibody drug conjugate belantamab mafodotin in combination with pomalidomide and dexamethasone on which he achieved a VGPR. In October 2020, he developed confusion and memory problems, as well as involuntary twitching. A brain MRI showed possible demyelination Two LPs were negative for JC virus, but a targeted brain biopsy confirmed the diagnosis of PML (Fig 1 D-F). His myeloma treatment was discontinued, and he was started on mirtazapine. At his most recent clinic visit in May 2021 his speech, memory and functional status had improved considerably and there were no signs of myeloma progression.ConclusionOur current series of PML in MM showcases the potential contribution of IMIDs and other novel agents–such as the newer monoclonal antibodies like belantamab mafotidin– to the reactivation of JC virus and subsequent PML. Our series also demonstrates that neurologic improvement and longer survival can be observed with earlier management. [Display omitted] DisclosuresReece: BMS: Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Millennium: Research Funding; GSK: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Honoraria; Karyopharm: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding.

Quality of Life and Caregiver Burden in Patients and Their Caregivers Undergoing Outpatient Autologous Stem Cell Transplantation Compared to Inpatient Transplantation

Quality of Life and Caregiver Burden in Patients and Their Caregivers Undergoing Outpatient Autologous Stem Cell Transplantation Compared to Inpatient Transplantation

Myeloma Patients with Deletion of 17p: Impact of Tandem Transplant and Clone Size

IntroductionThe presence of deletion 17p or monosomy 17 (del(17p)/-17) detected by fluorescence in situ hybridization (FISH) is well-established as a high-risk (HR) factor in multiple myeloma (MM). The del(17p)/-17 clone size and the clinical impact in patients that have ≥60% involved nuclei is controversial. Optimal treatment is also controversial, with tandem autologous stem cell transplantation (ASCT) explored but not uniformly adopted in the real world (ENM02, StaMMina). At our center, we have routinely offer tandem transplantation for del(17p)/-17 and now review our experience over a 10-year period, including the significance of del(17p)/-17 genetic variations on outcomes.MethodsWe performed a retrospective chart review of all patients identified with del(17p)/-17 patients who were offered tandem transplant and underwent at least one ASCT at Princess Margaret Cancer Centre from 2009-2019. Patient and disease characteristics, responses, and survival outcomes were collected from the Myeloma and Transplant databases and electronic patient records under REB approval.ResultsPatient, disease, and treatment characteristics.We identified 100 patients with del(17p)/-17 who underwent ASCT at our center. These patients were separated into three groups: those with a deletion of the TP53 locus (57%), those that had monosomy 14 (17%), and those with a relative loss the TP53 locus (eg. aneusomy or polyploidy,13%). The median % of nuclei with del(17p) was 39% (range 5-93%), with 27 (25%) over 60%. 28% of patients carried at least one other cytogenetic abnormality besides del(17p), most commonly t(4;14). All patients were intended for tandem transplant, but only 69 (69%) completed both transplants. Reasons for not proceeding to a second transplant were: patient declined (29%), toxicity (26%), clinical trial (19%), progression prior to the second transplant (13%), with one early death (3%). Median age at transplant was 61 years (range 40-72); most were male (61%) with advanced R-ISS II and III (97%).The most common induction regimen used was cyclophosphamide, bortezomib and dexamethasone (CYBORD)(87%), with 10% requiring a 2 nd induction regimen for inadequate response/progression. Standard conditioning was melphalan 200mg/m 2 for both first and second transplants. Median time from diagnosis to first ASCT was 5.9 months (range 3-24) and time from first to second transplant was 3.3 months (range 1-7). Most patients (90; 84%) received maintenance therapy post-transplant: 47% lenalidomide, 29% multiple agents (commonly lenalidomide and a proteasome inhibitor)Response and survival outcomesAfter induction, the rate of VGPR (very good partial response) or greater was 53%, increasing to 73% after 1 st ASCT, 85% after 2 nd ASCT. At a median follow-up of 32 months (range 3-130), the median PFS for all patients was 39.2 months 95% CI (24.1-46) and median OS was not yet reached (NYR) (95% CI 57.9-NYR). When analyzed by whether single or tandem transplant was performed, median PFS was 21.8 months (95% CI 10.3-43.3) for single ASCT, and 42.1 months (95% CI 32.8-NYR) for tandem ASCT (P=0.0096). The median OS was 57.6 months for single ASCT (95% CI 22.2-86.5), but NYR for tandem ASCT (95% CI 105.6-NYR) (p=0.0022).On subgroup analysis, patients with ≥60% del(17p) achieved a median PFS 45 months (95% CI 14.4-NYR) and median OS 68.5 months (95% CI 20.9-68.5), median was only PFS 24.9 months (95% CI0.4-NYR) and median OS 29.3 months (95% CI 0.4-68.5) for those who received single ASCT. (table1)TP53 signal pattern analysis (table 2) showed the median OS for patients with monosomy 17 was NYR, while it was 105.7 months for patients with deletion, and 86.5 months for those with relative loss. Median PFS was 43.3 months for the monosomy group, 32.8 months for deletion group, and NYR for relative loss.ConclusionsOur experience shows that MM patients with del(17p)/-17 appear to have deeper responses and improved outcomes with more aggressive tandem transplantation. However, approximately 1/3 of our patients intended for tandem transplant did not undergo a second transplant, identifying a focus of future investigation and optimization. Our analysis also suggests that clone size of del(17p) >60% does impact OS negatively, but improved with tandem transplantation. The type of deletion also appears to affect outcomes with deletion having worse PFS but not worse OS. [Display omitted] DisclosuresPrica: Astra-Zeneca: Honoraria; Kite Gilead: Honoraria. Reece: Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Millennium: Research Funding; Sanofi: Honoraria; BMS: Honoraria, Research Funding; Karyopharm: Consultancy, Research Funding; GSK: Honoraria. Trudel: Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Roche: Consultancy; Sanofi: Honoraria; Pfizer: Honoraria, Research Funding. Chen: Beigene: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy.

Clinical Significance of Clonal Hematopoiesis in the Setting of Autologous Stem Cell Transplantation for Lymphoma

Clinical Significance of Clonal Hematopoiesis in the Setting of Autologous Stem Cell Transplantation for Lymphoma

Single Centre, Retrospective Analysis of Extracorporeal Photopheresis (ECP) Therapy in the Patients Who Are Heavily Pre-Treated for Steroid Resistant Chronic Graft-Versus-Host Disease (GVHD)

*DB and DK contributed to the work equally.BackgroundExtracorporeal photopheresis (ECP) is a recommended second or later line of therapy for chronic GVHD (cGVHD), and is beneficial not only because of increased response but also for its lack of adverse effects, specifically systemic immune suppression, mainly from steroids. In this single centre study, we attempted to evaluate not only therapeutic efficacy of ECP, but also its steroid-sparing effect by regularly analyzing steroid dose per body weight. We also attempted to identify any predictors of response or survival after ECP, which was not well defined before.Patients and methodsA total of 75 cGVHD patients (pts) who received ECP for cGVHD from 2007 to 2021 at Princess Margaret Cancer Centre were included and evaluated retrospectively. Patients and disease characteristics are as follows: median age 48.5 years (range 17-70); male 42/75 (56%); organ involvement at the time of ECP: skin (93%), oral (53%), eye (51%), gastrointestinal (25%), liver (49%), lung (57%), and musculoskeletal (n=50, 67%). Sixty-eight (91%) and 7 pts (9%) had severe and moderate grade cGVHD, respectively. Sixty-eight pts (91%) received ECP as 4 th line or beyond. They were heavily pretreated with prednisone (98%), cyclosporine (57%), tacrolimus (24%), mycophenolate mofetil (64%), azathioprine (65%), rituximab (7%), imatinib (8%), ibrunitib (3%) and ruxolitinib (1%).ECP was started twice weekly for the first 12 weeks, then twice every 2 weeks in 2012-2021, while the schedule was twice every 2 weeks from 2007-2012. If there was no response or clinical benefit noted in first 24 treatments, then ECP was discontinued. In general, we attempted to provide up to around 60 sessions based on the clinicians' discretion.The overall response rate (ORR) and clinical benefit (CB) were assessed at months 3, 6 and 12 after staring ECP. As part of standard clinical practice, NIH consensus criteria were used for grading and response assessment. CB was assessed considering clinical response as well as steroid dose reduction. Treatment failure was defined as 1) resistance to ECP requiring treatment switch, 2) non-relapse mortality (NRM), 3) relapse, 4) intolerance to ECP. Failure free survival (FFS) and overall survival (OS)were calculated from the day of ECP initiation until the endpoints of failure or death, respectively.ResultsECP was started a median of 28 months (range 1-125) after development of cGVHD. ECP was performed a median of 35 times (range 6-174) with a median duration of 11 months (range 1-53). Out of 75 pts, 48 completed planned ECP successfully and 27 stopped due to no response or benefit including, of whom 14 required additional therapy, 1 stopped due to line infection, and 1 stopped due to relapse of AML.With a median 72 months of follow-up, ORR was attained in 21% (16/75), 57% (36/63) and 70% (32/46) at month 3, 6 and 12, respectively. At 6 months, ORR was observed in 47-64% across all organs assessed. No difference in ORR was noted according to the cGVHD grade; at 6 months, severe cGVHD showed similar ORR (57%) to those with moderate cGVHD (60%) (p=0.893). CB was noted in 23% (17/75), 62% (39/63), and 76% (35/46) at month 3, 6 and 12, respectively.A total of 27/75 failures (36%) and 20/75 death (27%) occurred, due to the following: ECP resistance requiring switch to other therapy (n=14, 19%), NRM (n=11, 15%), relapse of primary disease (n=1, 1%) or ECP-related complication (n=1, 1%, line infection). In the overall cohort, FFS and OS at 12 months were 68.3% and 85.9%, respectively (Figure 1).More than a half of pts stopped steroids completely within 12 months after starting ECP. The proportion of pts off steroids was 16%, 17%, 32%, and 64% at month 0, 3, 6 and 12 after starting ECP, respectively (Figure 2).Risk factor analysis did not show any predictive markers for ORR at 6 months, while prognostic factor analysis suggested the development of musculoskeletal involvement as favorable prognostic factor for FFS (p=0.003, HR 0.315 [0.147, 0.673]) even with multivariate analysis.ConclusionOur study showed that: 1) ECP is a very effective treatment for heavily pre-treated cGVHD pts who have failed other therapies; 2) More than a half of pts can stop steroids completely within 12 months after starting ECP, thus avoiding long-term toxicity risk. Further study is warranted comparing ECP with other cGVHD treatment modalities. [Display omitted] DisclosuresPatriquin: BioCryst Pharmaceuticals: Honoraria; Alexion: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Apellis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria. Law: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company. Kim: Paladin: Consultancy, Honoraria, Research Funding; Bristol-Meier Squibb: Research Funding; Pfizer: Honoraria; Novartis: Consultancy, Honoraria, Research Funding.

Risk Stratification for Relapsed/Refractory Classical Hodgkin Lymphoma Integrating Pretransplant Deauville Score and Residual Metabolic Tumor Volume

IntroductionPositron emission tomography (PET) positivity before autologous stem cell transplantation (ASCT) predicts poor prognosis in relapsed/refractory (rel/ref) classical Hodgkin lymphoma (cHL). However, there is limited data regarding the value of pre-ASCT residual metabolic tumor volume (rMTV) assessed by PET to predict post-ASCT outcomes. We aimed to evaluate the role of pre-ASCT Deauville score (DS) combined with rMTV in patients with rel/ref cHL who underwent salvage ASCT, and also to establish a risk model integrating pre-ASCT DS, rMTV, and other clinical risk factors.MethodsThis is a retrospective cohort study using clinical data of patients with rel/ref cHL identified from the lymphoma database and the ASCT database of the Princess Margaret Cancer Center, Toronto, Canada. Following criteria were required: (1) patients (≥18 yrs) with histologically confirmed rel/ref cHL between January 2014 to March 2019; (2) treatment with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) or ABVD-equivalent regimens; (3) chemosensitive disease after salvage therapy; (4) restaging PET before ASCT clearance. Pre-ASCT PET scans were assessed using the Deauville 5-point scale, and rMTV was computed in the scans with DS 4 or 5 using the 41% maximum standardized uptake value threshold method. Receiver operating characteristics analysis was used to determine an optimal cutoff of rMTV 41% for event prediction. The primary endpoint was event-free survival (EFS), defined as time form ASCT to first documented disease progression, any new lymphoma therapy, death from any cause, or last follow-up.ResultsA total of 106 patients fulfilled the eligibility criteria and were included. Median age was 33.5 yrs (range, 18-70), and 72 (68%) were male. The cohort characteristics at time of progression were 55 (52%) patients with advanced stage, 28 (26%) with B symptoms, 39 (37%) with extranodal disease, and 39 (37%) with primary refractory disease, defined as achieving less than a complete response, disease progression during first-line therapy, or time to relapse (TTR) 3 months or less. All patients received gemcitabine, dexamethasone, cisplatin (GDP) regimen as salvage therapy. Based on the response to GDP therapy, 24 patients required second (N=20) or third (N=4) salvage regimens before ASCT (brentuximab vedotin [BV] alone or combination with bendamustine [N=16], pembrolizumab [N=9], and mini-BEAM [N=3]). 32 patients (30%) received planned pre- or post-ASCT involved field radiation for DS 4-5 lesions. 4 patients received post-ASCT BV consolidation.With a median follow-up of 26.2 months (interquartile range [IQR], 14.4-49.2), 2-year EFS and overall survival rates were 72.1% and 93.1%, respectively. Pre-ASCT DS was determined as 1-3 (N=63, 59%) and 4-5 (N=43, 41%). None of the patients with DS 5 had new lesions. Patients with pre-ASCT DS 1-3 had significantly better EFS than those with DS 4-5 (2-year; 80.8% vs 59.2%; P=0.002; Fig 1A).Median rMTV 41% of the 43 patients with DS 4-5 was 5.1 cm 3 (IQR, 2.0-24.7). The optimal cutoff of rMTV 41% was 4.4 cm 3. Patients with rMTV low (< 4.4cm 3, N=21) had better EFS than those with rMTV high (N=22; 2-year, 75.0% vs 45.4%; P=0.009), but had similar 2-year EFS when compared with patients with DS 1-3 (80.8%, P=0.280; Fig 1B)In the multivariable analysis for EFS, a combined assessment of pre-ASCT DS/rMTV 41% and rel/ref status at time of progression were independently associated with EFS (for DS 4-5/rMTV low, hazard ratio [HR] 1.58; for DS 4-5/rMTV high, HR 4.72; P<0.001: for primary refractory disease, HR 2.26; P=0.026). Based on these results, we stratified patients into 3 groups according to the post-ASCT outcomes: low-risk (relapsed disease [i.e., TTR > 3 months] and either pre-ASCT DS 1-3 or DS 4-5/rMTV low, N=54), intermediate-risk (refractory disease and either pre-ASCT DS 1-3 or DS 4-5/rMTV low, N=30), and high-risk (pre-ASCT DS 4-5/rMTV high irrespective of rel/ref status, N=22) groups. The risk model was significantly associated with EFS (intermediate vs low, HR 3.26, 95%CI 1.20-8.83, P=0.020; high vs low, HR 7.61, 95% CI 2.89-20.01, P<0.001; Fig 1C).ConclusionWe propose a risk stratification model integrating a combination of DS and rMTV 41% on pre-ASCT PET and rel/ref status at time of progression, which allow discrimination of post-ASCT outcomes in patients with rel/ref cHL. The model may serve as a tool to facilitate risk-stratified treatment decisions. [Display omitted] DisclosuresMetser: POINT Biopharm Inc: Consultancy. Prica: Astra-Zeneca: Honoraria; Kite Gilead: Honoraria. Crump: Roche: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Epizyme: Research Funding; Kyte/Gilead: Membership on an entity's Board of Directors or advisory committees. Kuruvilla: Seattle Genetics: Honoraria; Amgen: Honoraria; Antengene: Honoraria; AbbVie: Honoraria; Janssen: Honoraria, Research Funding; BMS: Honoraria; Medison Ventures: Honoraria; TG Therapeutics: Honoraria; AstraZeneca: Honoraria, Research Funding; Gilead: Honoraria; Incyte: Honoraria; Karyopharm: Honoraria, Other: Data and Safety Monitoring Board; Roche: Honoraria, Research Funding; Novartis: Honoraria; Merck: Honoraria; Pfizer: Honoraria. Kridel: Gilead Sciences: Research Funding.

Dynamic Stromal Changes in Myelofibrosis Patients Pre/Post JAK Inhibition Is Revealed in Clinically Archived Bone Marrow Biopsies By Smooth Muscle Actin (SMA)-CD34 Dual Immunohistochemistry

The natural history of BCR-ABL1 negative myeloproliferative neoplasms (MPNs) is progression towards an overt myelofibrotic (MF) phase with variable risk to develop secondary acute myeloid leukemia. Current treatments include Janus kinase inhibitors (JAKi) which can temporarily alleviate MF-related symptoms but are non-curative and most patients eventually progress to a more advanced stage. Given the negative prognostic impact of bone marrow fibrosis in MPNs and generally poor outcome post JAKi failure, it would be important to identify in situ biomarkers that address the initiation, perpetuation and early reversal of the fibrotic reaction.The current clinical standard for bone marrow fibrosis assessment involves reticulin/trichrome stains that detect relatively static extracellular matrix products rather than the fibrosis driving cells directly. To address this, we have developed a smooth muscle actin stromal-vascular (SMA-CD34) dual immunohistochemical (IHC) technique amenable to morphologic scoring and complemented with a CellProfiler image analysis pipeline. SMA was prioritized over other validated stromal IHC markers given work by others in experimental models demonstrating SMA+ myofibroblasts to be the differentiated output of critical fibrosis inducing Gli1+ ‘driver’ mesenchymal stem/progenitor cells in MPN.Herein, we demonstrate the feasibility of our translational approach using a clinically annotated cohort of MF patients from the Princess Margaret Cancer Centre MPN Registry. After selecting for high quality (>1.0 cm) paired pre and post JAKi biopsies amenable to image and transcriptome-based analysis, the pilot cohort was comprised of 13 cases with 38% high-risk, 54% intermediate-2 and 8% intermediate-1 risk by DIPSS. Driver mutations were JAK2 V617F (77%), CALR (15%) and other (8%). JAKi therapies included ruxolitinib (31%) + pelabresib (23%), momelotinib (15%), itacitinib (15%) and pacritinib (8%).The SMA-CD34 stromal assessment at baseline revealed distinct interstitial myofibroblast patterns and vascular perturbations not captured by conventional clinical hematopathology assessment (e.g. SMA+ dilated sinusoids). A SMA-CD34 scoring system was developed using a 4-point scale representing normal (0 pts), increased vascularity (1 pt), focal interstitial SMA (2 pts), multifocal interstitial SMA (3 pts) and diffuse SMA (4 pts). Scoring was then performed by blinded hematopathologists. A trend towards JAK2 mutated MF cases demonstrating higher SMA grade at baseline was noted. Interestingly, variable trajectories in SMA scores emerged following treatment with JAKi. Specifically, SMA signals had increased in 15%, decreased in 46% and were stable in 38% post-JAKi when using a morphologic SMA grading scheme. When compared to reticulin fibrosis, the severity of SMA signals had diverged in 1/3 of the cases (e.g. SMA grade decreased, reticulin grade stable).To further complement the SMA-CD34 morphologic grading, a CellProfiler image analysis pipeline was developed yielding a non-vessel associated normalized SMA area metric as a supervised correlate of the clinical SMA scoring system (R 2 = 0.68). Additional supervised and unsupervised bioinformatic approaches for clustering of relevant SMA-CD34 features including an algorithm that informs SMA spatial patterns with respect to niche elements such as arterioles (CD34+SMA+), sinusoids (CD34+) and adipocytes is in development.Lastly, Nanostring Fibrosis V2 panel was employed on a subset that met RNA concentration and quality metrics. Exploratory interpretation showed significant differentially expressed genes in pre vs. post JAKi specimens related to lipid metabolism such as ADIPOR1, SCD, ELOVL6 as well as the chemokine CXCL16. This may suggest a link between fatty acid metabolism and inflammatory differentiation along the SMA-vascular axis in the bone marrow modulated by JAKi treatment.SMA-CD34 IHC stratifies MF bone marrow biopsies differentially from standard WHO reticulin/trichome grading providing a practical formalin-fixed paraffin embedded (FFPE) tissue-based biomarker for assessing fibrosis related bone marrow niche elements from archived clinical samples. While our pilot numbers precluded statistical evaluation by JAKi-type, clinical response and NGS mutational profile at this time, further studies are underway to validate the SMA-CD34 signature on a larger MF cohort. [Display omitted] DisclosuresGupta: Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy; Incyte: Honoraria, Research Funding; Constellation Pharma: Consultancy, Honoraria; Pfizer: Consultancy.