Complete Remission Duration Research Articles

Long-term three-year follow-up of mosunetuzumab in relapsed or refractory follicular lymphoma after ≥2 prior therapies (119/120)

Mosunetuzumab, a CD20xCD3 T-cell engaging bispecific antibody, redirects T cells to eliminate malignant B cells. We present updated efficacy and safety data of a pivotal phase 1/2 study after a median follow-up of 37.4 months in 90 patients with relapsed/refractory (R/R) follicular lymphoma (FL) and ≥2 prior lines of therapy treated with fixed-duration mosunetuzumab. Investigator-assessed complete response (CR) rate and objective response rate (ORR) were 60.0% (95% confidence interval [CI], 49.1-70.2) and 77.8% (95% CI, 67.8-85.9), respectively. Among 70 responders, median duration of response was 35.9 months (95% CI, 20.7-not estimable [NE]). Among 54 patients who achieved CR, 49 remained in CR at the end of treatment; median duration of complete response was not reached (NR) (95% CI, 33.0-NE); Kaplan-Meier-estimated 30-month remission rate was 72.4% (95% CI, 59.2-85.6). Estimated 36-month overall survival (OS) rate was 82.4% (95% CI, 73.8-91.0); median OS was NR (95% CI, NE-NE). Median progression-free survival was 24.0 months (95% CI, 12.0-NE). Median time to CD19+ B-cell recovery was 18.4 months (95% CI, 12.8-25.0) following 8 cycles of mosunetuzumab treatment. No new cytokine release syndrome events or fatal, serious, or Grade ≥3 adverse events were reported. With extended follow-up, mosunetuzumab demonstrated high response rates, durable remissions and manageable safety with no long-term concerns. This supports outpatient mosunetuzumab administration as an off-the-shelf, fixed-duration, safe and effective treatment for patients with R/R FL, including those with high-risk disease. Trial registration: www.clinicaltrials.gov (NCT02500407).

Characteristics and Prognosis of Patients with Advanced Hepatocellular Carcinoma Treated with Atezolizumab/Bevacizumab Combination Therapy Who Achieved Complete Response.

To investigate the characteristics and prognosis of patients with advanced hepatocellular carcinoma (HCC) treated with atezolizumab and bevacizumab (Atz/Bev) who achieved a complete response (CR) according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). A total of 120 patients with Eastern Cooperative Oncology Group performance status (PS) 0 or 1 and Child-Pugh A at the start of Atz/Bev treatment were included. Barcelona Clinic Liver Cancer stage C was recorded in 59 patients. The CR rate with Atz/Bev alone was 15.0%. The median time to CR was 3.4 months, and the median duration of CR was 15.6 months. A significant factor associated with achieving CR with Atz/Bev alone was an AFP ratio of 0.34 or less at 3 weeks. Adding transarterial chemoembolization (TACE) in the six patients who achieved a partial response increased the overall CR rate to 20%. Among the 24 patients who achieved CR, the median progression-free survival was 19.3 months, the median overall survival was not reached, and 14 patients (58.3%) were able to discontinue Atz/Bev and achieve a drug-free status. Twelve of these patients developed progressive disease (PD), but eleven successfully received post-PD treatments and responded well. Achieving CR by mRECIST using Atz/Bev alone or with additional TACE can be expected to offer an extremely favorable prognosis.

Nanoparticles use magnetoelectricity to target and eradicate cancer cells.

We investigated the theranostic capabilities of magnetoelectric nanoparticles (MENPs) combined with MRI via a murine model of pancreatic adenocarcinoma. MENPs leverage the magnetoelectric effect to convert an applied magnetic field into local electric fields, which can induce irreversible electroporation of tumor cell membranes when activated by MRI. Additionally, MENPs modulate MRI relaxivity, which can be used to predict the degree of tumor ablation. Through a pilot study (n=21) and a confirmatory study (n=27), we demonstrated that, ≥300 µg of MRI-activated MENPs significantly reduced tumor volumes, averaging a three-fold decrease as compared to controls. Furthermore, there was a direct correlation between the reduction in tumor T 2 relaxation times and tumor volume reduction, highlighting the predictive prognostic value of MENPs. Six of 17 mice in the confirmatory study's experimental arms achieved a durable complete response, showcasing the potential for durable treatment outcomes. Importantly, the administration of MENPs was not associated with any evident toxicities. This study presents the first in vivo evidence of an externally controlled, MRI-based, theranostic agent that effectively targets and treats solid tumors via irreversible electroporation while sparing normal tissues, offering a new and promising approach to cancer therapy.

Durable Remission After Targeted Therapy in BRAF V600E–Mutant Metastatic Colorectal Cancer: Case Report

ABSTRACT BRAF mutation leads to constitutive activation of the MAPK pathway and is associated with the immune-activating molecular subtype of colorectal cancer. Targeted therapy for BRAF V600E–mutant metastatic colorectal cancer (CRC) has significantly improved outcomes for these patients when combined with anti–epithelial growth factor receptor (EGFR) therapy. However, most patients ultimately develop disease progression. We report a case of a patient with metastatic-deficient mismatch repair, BRAF V600E–mutated CRC, who achieved a durable complete response to vemurafenib plus cetuximab and chemotherapy despite initial high burden of disease, including peritoneal involvement. Recent clinical trials of combined anti-EGFR/anti–BRAF V600E therapy in BRAF V600E-mutant CRCs have found a few instances of robust response. Further study of combined targeted and chemotherapeutic regimens and the immunogenic properties of BRAF mutation may yield promising results.

Short-Course TNT Improves Rectal Tumor Downstaging in a Retrospective Study of the US Rectal Cancer Consortium.

The RAPIDO trial showed promising rates of pathologic complete response (pCR) after neoadjuvant short-course radiation with consolidation chemotherapy (total neoadjuvant therapy [SC TNT]) for rectal cancer. Only single-center reviews comparing tumor downstaging between SC TNT and long-course chemoradiation (LCRT) have been published in the United States. We reviewed our multi-institutional experience with both. The US Rectal Cancer Consortium database (2007-2018) including data from six high-volume rectal cancer care centers was reviewed. Patients with nonmetastatic, rectal adenocarcinoma who had neoadjuvant LCRT alone or SC TNT before excision or definitive nonoperative management were included. The primary outcome was the rate of complete response (CR), including pCR or durable (12 month) clinical complete response. Of 857 included patients, 175 (20%) received SC TNT and 682 (80%) received LCRT. The LCRT group had more low tumors (51.8% vs. 37.1%, p < 0.0001) and more clinically node-negative disease (31.8% vs. 22.3%, p < 0.0001). The CR rate was higher after SC TNT (34.1% vs. 20.3%, p = 0.0001). SC TNT was a predictor of CR (OR: 2.52, CI: 1.68-3.78). SC TNT patients completing 5-6 months of consolidation chemotherapy had a CR rate of 42.9%. There was no difference in 3-year PFS. SC TNT increases CR rate when compared to LCRT. For patients seeking nonoperative options or fewer radiation treatments, SC TRT should be preferred over LCRT alone.

Glofitamab in Relapsed/Refractory Mantle Cell Lymphoma: Results From a Phase I/II Study.

Patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL) have a poor prognosis. The phase I/II NP30179 study (ClinicalTrials.gov identifier: NCT03075696) evaluated glofitamab monotherapy in patients with R/R B-cell lymphomas, with obinutuzumab pretreatment (Gpt) to mitigate the risk of cytokine release syndrome (CRS) with glofitamab. We present data for patients with R/R MCL. Eligible patients with R/R MCL (at least one previous therapy) received Gpt (1,000 or 2,000 mg) 7 days before the first glofitamab dose (single dose or split over 2 days if required). Glofitamab step-up dosing was administered once a day on days 8 (2.5 mg) and 15 (10 mg) of cycle 1, with a target dose of 16 or 30 mg once every 3 weeks from cycle 2 day 1 onward, for 12 cycles. Efficacy end points included investigator-assessed complete response (CR) rate, overall response rate (ORR), and duration of CR. Of 61 enrolled patients, 60 were evaluable for safety and efficacy. Patients had received a median of two previous therapies (range, 1-5). CR rate and ORR were 78.3% (95% CI, 65.8 to 87.9) and 85.0% (95% CI, 73.4 to 92.9), respectively. In patients who had received previous treatment with a Bruton tyrosine kinase inhibitor (n = 31), CR rate was 71.0% (95% CI, 52.0 to 85.8) and ORR was 74.2% (95% CI, 55.4 to 88.1). CRS after glofitamab administration occurred in 70.0% of patients, with a lower incidence in the 2,000 mg (63.6% [grade ≥2, 22.7%]) versus 1,000 mg (87.5%; grade ≥2, 62.5%) Gpt cohort. Four adverse events led to glofitamab withdrawal (all infections). Fixed-duration glofitamab induced high CR rates in heavily pretreated patients with R/R MCL; the safety profile was manageable with appropriate support.

Combined KRAS inhibition and immune therapy generates durable complete responses in an autochthonous PDAC model.

Pancreatic ductal adenocarcinoma (PDAC) resists conventional chemo/radiation and immunotherapy. In PDAC, oncogenic KRAS (KRAS*) drives glycolysis in cancer cells to consume available glucose and produce abundant lactate, creating profound immune suppression in the tumor microenvironment. Here, we combined KRAS* inhibition with agents targeting the major arms of the immunity cycle: CXCR1/2 inhibitor for myeloid cells, antagonistic anti-LAG3 antibody for T cells, and agonistic anti-41BB antibody for dendritic cells. This combination elicited robust anti-tumor regression in iKPC mice bearing large autochthonous tumors. While untreated mice succumbed within 3 weeks, sustained treatment led to durable complete tumor regression and prolonged survival in 36% of mice at 6 months. Mechanistic analyses revealed enhanced T cell infiltration and activation, depletion of immunosuppressive myeloid cells, and increased antigen cross-presentation by dendritic cells within the tumor core. These findings highlight the promise of KRAS* inhibitors alongside immunotherapy as a potential PDAC treatment avenue, warranting clinical investigation.

Randomized Phase III SIERRA Trial of 131I-Apamistamab Before Allogeneic Hematopoietic Cell Transplantation Versus Conventional Care for Relapsed/Refractory AML

PURPOSE Older patients with relapsed or refractory AML (RR AML) have dismal prognoses without allogeneic hematopoietic cell transplantation (alloHCT). SIERRA compared a targeted pretransplant regimen involving the anti-CD45 radioconjugate 131I-apamistamab with conventional care. METHODS SIERRA (ClinicalTrials.gov identifier: NCT02665065 ) was a phase III open-label trial. Patients age ≥55 years with active RR AML were randomly assigned 1:1 to either an 131I-apamistamab–led regimen before alloHCT or conventional care followed by alloHCT if initial complete remission (CR)/CR with incomplete platelet recovery (CRp) occurred. Initial response was assessed 28-56 days after alloHCT in the 131I-apamistamab group and 28-42 days after salvage chemotherapy initiation; patients without CR/CRp or with AML progression could cross over to receive 131I-apamistamab followed by alloHCT. The primary end point was durable complete remission (dCR) lasting 180 days after initial CR/CRp. Secondary end points were overall survival (OS) and event-free survival (EFS), assessed hierarchically in the intention-to-treat (ITT) population. RESULTS The ITT population included 153 patients (131I-apamistamab [n = 76]; conventional care [n = 77]). In total, 44/77 conventional care arm patients crossed over and 40/77 (52%) received 131I-apamistamab and alloHCT, with six patients (13.6%) experiencing a dCR. In the ITT population, the dCR rate was significantly higher with 131I-apamistamab (17.1% [95% CI, 9.4 to 27.5]) than conventional care (0% [95% CI, 0 to 4.7]; P &lt; .0001). The OS hazard ratio (HR) was 0.99 (95% CI, 0.70 to 1.41; P = .96), and the EFS HR was 0.23 (95% CI, 0.15 to 0.34), with HR &lt;1 favoring 131I-apamistamab. Grade ≥3 treatment-related adverse events occurred in 59.7% and 59.2% of the 131I-apamistamab and conventional care groups, respectively. CONCLUSION The 131I-apamistamab–led regimen was associated with a higher dCR rate than conventional care in older patients with RR AML. 131I-apamistamab was well tolerated and could address an unmet need in this population.

Redefining YAP1 in small cell lung cancer: shifting from a dominant subtype marker to a favorable prognostic indicator.

Molecular and transcription factor subtyping were recently introduced to identify patients with unique clinical features in small cell lung cancer (SCLC). However, its prognostic relevance is yet to be established. This study aims to investigate the clinical implications and prognostic significance of transcription factor subtyping in SCLC using immunohistochemistry. One hundred and ninety consecutive SCLC patients treated with platinum-based chemotherapy at a single institution were retrospectively reviewed. Expression of ASCL1, NeuroD1, POU2F3, and YAP1 was assessed by immunohistochemical staining and applied to determine the transcription factor subtype of each case. The association among transcription factors was not entirely mutually exclusive. YAP1 expression was the most significant prognostic indicator compared with other transcription factors or their related subtypes. Among patients with limited-stage disease (LD), complete response (CR) rates were 46.2% and 22.4% in the YAP1-positive and YAP1-negative groups, respectively. The median duration of response among patients who achieved CR was 64.8 and 36.4 months in the YAP1-positive and YAP1-negative groups, respectively (P=0.06). Median overall survival (OS) in LD was 35.6 and 16.9 months in the YAP1-positive and YAP1-negative groups, respectively (P=0.03). In extensive-stage disease (ED), the median OS was 11.3 months for the YAP1-positive group and 11 months for the YAP1-negative group (P=0.03). Positive expression of YAP1 can be associated with durable CR and favorable survival outcomes in patients with SCLC, especially in LD.

Durable complete response after combined treatment with tumor-infiltrating lymphocytes and oncolytic adenovirus (TILT-123) in a patient with metastatic mucosal melanoma

Durable complete response after combined treatment with tumor-infiltrating lymphocytes and oncolytic adenovirus (TILT-123) in a patient with metastatic mucosal melanoma

Safety and efficacy of odronextamab in patients with relapsed or refractory follicular lymphoma

Odronextamab, a CD20×CD3 bispecific antibody that engages cytotoxic T cells to destroy malignant B cells, has demonstrated encouraging activity across multiple subtypes of relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma. This phase II study (ELM-2; NCT03888105) evaluated odronextamab in patients with R/R follicular lymphoma after two or more lines of systemic therapy. Patients received intravenous odronextamab in 21-day cycles, with step-up dosing in cycle 1 to help mitigate the risk of cytokine release syndrome, until disease progression or unacceptable toxicity. The primary endpoint was objective response rate by independent central review. Among 128 patients evaluated, 95% completed cycle 1, and 85% completed four or more cycles. At 20.1months' efficacy follow-up, objective response rate was 80.0% and complete response rate was 73.4%. Median duration of complete response was 25.1 months. Median progression-free survival was 20.7 months, and median overall survival was not reached. Discontinuation of odronextamab due to adverse events occurred in 16% of patients. The most common treatment-emergent adverse events were cytokine release syndrome [56%; grade ≥31.7% (1/60) with 0.7/4/20 mg step-up], neutropenia (39%), and pyrexia (38%). Odronextamab achieved high complete response rates with generally manageable safety in patients with heavily pretreated R/R follicular lymphoma.

Perceptions and Expectations: A Study on Prognostic Perception and Quality of Life in Patients With Metastatic Renal and Bladder Cancer.

Durable complete response rates for metastatic renal cell carcinoma (mRCC) and metastatic bladder cancer (mBC) are low despite new therapy. Palliative care focuses on life extension and quality of life (QoL), not cure. This study aims to investigate patients' perceptions of treatment outcomes in mRCC and mBC and to assess the influence of QoL and optimism levels on these perceptions. From March 15, 2023, to January 15, 2024, a multicenter, cross-sectional online survey was carried out, targeting patients diagnosed with mRCC and mBC. The survey comprised structured questions aimed at evaluating perceptions concerning disease cure, symptom improvement, daily activity performance, and life extension due to treatment. Additionally, to evaluate optimism and QoL, the European Organization for Research and Treatment of Cancer 30.3 QoL questionnaire and life orientation test were implemented. Study on patients' perceptions of treatment outcomes in metastatic kidney and bladder cancer shows high optimism, inaccurate cure beliefs. In total, 169 patients participated in the survey; the majority of the patients stated their general health status as good (72.2%) and excellent (13.6%). Patients who rated their overall health status as good-excellent had a higher median general QoL and optimism score compared with those who rated it as fair-poor. In all, 85.2% of patients considered the possibility of a cure very likely or likely. Most participants believed treatment could provide symptom relief (30.2% very likely, 49.1% likely), enhanced ability to perform daily activities (28.4% very likely, 55.6% likely), and life extension (32.5% very likely, 53.3% likely). Patients responding very likely and likely to these questions regarding treatment outcomes had higher QoL and optimism scores than those responding a little likely and not possible. The majority of patients with mRCC and mBC held inaccurate beliefs about treatment outcomes. Better QoL and optimism were associated with increased inaccuracy.

Intratumoral T-cell composition predicts epcoritamab-based treatment efficacy in B-cell non-Hodgkin lymphomas.

Leveraging endogenous tumor-resident T-cells for immunotherapy using bispecific antibodies (BsAb) targeting CD20 and CD3 has emerged as a promising therapeutic strategy for patients with B-cell non-Hodgkin lymphomas. However, features associated with treatment response or resistance are unknown. To this end, we analyzed data from patients treated with epcoritamab-containing regimens in the EPCORE NHL-2 trial (NCT04663347). We observed downregulation of CD20 expression on B-cells following treatment initiation both in progressing patients and in patients achieving durable complete responses (CR), suggesting that CD20 downregulation does not universally predict resistance to BsAb-based therapy. Single-cell immune profiling of tumor biopsies obtained following one cycle of therapy revealed substantial clonal expansion of cytotoxic CD4+ and CD8+ T-cells in patients achieving CR, and an expansion of follicular helper and regulatory CD4+ T-cells in patients whose disease progressed. These results identify distinct tumor-resident T-cell profiles associated with response or resistance to BsAb therapy.

On the Way to Curing Advanced-Stage Mycosis Fungoides/Sézary Syndrome

Advanced-stage mycosis fungoides (MF) and Sézary syndrome (SS) have poor prognosis with median survivals of less than 5 years. Although a variety of treatments are approved for MF/SS patients, durable complete remissions (CR) are rare. Advanced-stage MF or SS patients who achieved CR and maintained in CR or stage IA for more than 10 years were identified by a retrospective search of the principal investigator's database. Of 2266 patients diagnosed with MF or SS, 23 patients with advanced-stage MF/SS (6 IIB, 1 IIIB, 5 IVA1, 3 IVA2, 8 IVB) who achieved CR and maintained in CR or stage IA for ≥ 10 years were identified. As final/curative treatment, 11 patients underwent allogeneic stem cell transplantation (SCT). Most patients presented at young age, underwent SCT with reduced intensity conditioning regimen, had matched related donors, and controllable post-transplant graft versus host disease. Eleven patients were treated with TSEB as part of combined modality protocol in 2 patients and debulking therapy before allogeneic SCT in 9 patients. Five stage IIB patients achieved CR with radiotherapy. Four patients with blood involvement were treated with extracorporeal photopheresis (ECP) in combination with long-term antibiotics and immunomodulatory agents. Long-term antibiotics were given to 14 patients. TSEB followed by allogeneic SCT, radiotherapy, ECP plus long-term antibiotics and immunomodulatory agents were the most common curative/final treatments found in our patients. We are reporting the details of our long-term complete responders' treatment course in the hopes of obtaining more cure responses in the future.

Outcomes of children treated for relapsed or refractory acute lymphoblastic leukemia: A single tertiary care center experience.

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies among children. Despite success in frontline treatment, 20% of children will relapse or show resistance to treatment. The aim of this study is to evaluate the clinical characteristics of children diagnosed and treated for refractory or relapsed ALL and determine 3-year overall survival (OS) outcomes. This study involved a retrospective chart review of patients aged 1-14 years diagnosed with ALL during January 2002 to December 2018. Data were extracted for baseline characteristics at diagnosis and at relapse. A total of 347 newly diagnosed children with ALL were identified, among whom there were three induction failures (IF) and 28 relapses, resulting in a cohort of 31 patients with a relapse rate of 9%. The male-to-female ratio was 4.16:1, and the mean duration of first complete remission (CR1) was 26 months. Fifteen (48%) patients relapsed ≤18 months, 7 (23%) during 18-36 months, and 9 (29%) relapsed >36 months of IF or CR1. Nineteen patients (61%) had isolated bone marrow (BM) relapse, 7 (23%) patients experienced isolated extramedullary relapse (5 isolated CNS relapse and 2 isolated testicular relapse), and 5 (16%) patients experienced BM involvement with other sites (4 BM + CNS and 1 BM + testis). The 3-year OS of the cohort was 62.3%, while in patients with CR post first-salvage therapy, a 3-year OS of 79.5% was observed (p value <.05 compared with patients who did not achieve remission post first-salvage therapy, 3-year OS: 46.4%). The same statistical difference was observed in 3-year OS when comparing the duration of remission of CR prior to relapse: ≤18 months, 33.2%; 18-36 months, 66.7%; and >36 months, 87.5%. The same trend continued when comparing 3-year OS based on risk stratification at relapse: low risk (LR), 83.3%; intermediate risk (IR), 80%; and high risk (HR), 44.8%. The incidence and outcomes reported are comparable to internationally reported data regarding the duration of CR1. Risk stratification at relapse and remission status post-salvage therapy were identified as significant prognostic factors for survival. No survival difference was observed among patients who received hematopoietic stem cell transplantation after induction compared with those who received chemotherapy, which could be attributed to the smaller sample size, warranting a multi-institutional observational study. These findings corroborate the need for novel therapies and treatment approaches.

Ivosidenib in Chinese patients with relapsed or refractory isocitrate dehydrogenase 1 mutated acute myeloid leukemia: a registry study.

Ivosidenib, an isocitrate dehydrogenase 1 (IDH1) inhibitor, has demonstrated clinical benefits in a pivotal study (AG120-C-001) in patients with IDH1-mutated (mIDH1) acute myeloid leukemia (AML). A registry study (CS3010-101: NCT04176393) was conducted to assess the pharmacokinetic (PK) characteristics, safety, and efficacy of ivosidenib in Chinese patients with relapsed or refractory (R/R) mIDH1 AML. Patients received ivosidenib 500 mg once daily for 28-day cycles until disease progression. Ten subjects underwent intensive PK/progressive disease (PD) assessments. All subjects had the clinical response assessed at screening, every 28 days through month 12, and then every 56 days. Between November 12, 2019, and April 2, 2021, 30 patients were enrolled; 26 (86.7%) had de novo AML and 18 (60.0%) were transfusion-dependent at baseline. Following single and repeated doses of ivosidenib, median time to maximum plasma concentration (T max) was 4.0 and 2.0 hours, respectively. The inter-individual variability of pharmacokinetic exposure was moderate to high (coefficient of variation [CV], 25%-53%). No obvious accumulation was observed after repeated doses at cycle 2 day 1. Regarding the clinical response, the CR + CRh rate was 36.7% (95% confidence interval [CI]: 19.9%-56.1%), the median duration of CR + CRh was 19.7 months (95% CI: 2.9 months-not reached [NR]), and median duration of response (DoR) was 14.3 months (95% CI: 6.4 months-NR). Consistent clinical benefits and safety of ivosidenib were consistently observed at the final data cutoff with median follow-up time 26.0 months, as compared with primary data cutoff, and the data from Chinese R/R mIDH1 AML patients were also consistent with results from pivotal study.

Abstract PO-007: A phase 1 study of romidepsin, azacitidine, dexamethasone, and lenalidomide (RAdR) for relapsed/refractory T-cell malignancies

Abstract Romidepsin, azacitidine and lenalidomide are all active in T-cell malignancies (TCM) demonstrating single agent objective response rates (ORR) of 20 to 30% (Coiffier 2012; Morschhauser 2013; Dupuis 2022). Combinations of these targeted agents improves the rates of complete response (CR) but have significant toxicity due to indefinite schedules. We hypothesized that use of a multi-targeted therapy regimen such as RAdR given in fixed duration cycles would be safe and effective. We tested escalating doses of lenalidomide (5-20mg) with fixed doses of romidepsin, azacitidine and dexamethasone in a phase 1 study. Patients (pts) first received a 7-day window of lenalidomide for cytokine correlative research followed by six cycles of romidepsin (12mg/m2; days 1 and 10), azacitidine (300mg; days 1-10), dexamethasone (40mg; days 1 and 10), and lenalidomide (5-20mg; days 1-10) in 21-day cycles for up to 6 cycles. The primary endpoint was the maximum tolerated dose (MTD) of lenalidomide and the primary objective was the overall safety of the regimen. A 3+3 design was used with an additional 9 pts treated at the MTD. 26 pts were enrolled with a median age of 61 years (range, 28-80) including 31% over 65. Eight (31%) pts had PTCL, NOS, 6 (23%) had mycosis fungoides (MF), 5 (19%) had angioimmunoblastic T-cell lymphoma, and 4 (15%) ATLL. Median prior lines of therapy were 2 (range, 1-8), 31% had received &amp;gt;3 prior lines and 2 patients had received prior allogeneic transplantation. The median number of cycles was 4 (range, &amp;lt;1-6). The most frequent reasons for stopping therapy were progressive disease (38%), completion of planned therapy (27%) and adverse events (23%). The most frequent grade 1-2 non-hematologic adverse events were vomiting (52%), diarrhea (48%) and dysgeusia (48%), and AE grade 3+ included infection (16%) and hypokalemia (16%). Grade 3+ neutropenia occurred in 24% of cycles and both grade 3+ anemia and thrombocytopenia in 12% of cycles. Two DLTs were observed, grade 4 thrombocytopenia at dose level 1 and grade 3 abdominal pain at dose level 2. The MTD of lenalidomide was determined to be 20mg. In evaluable pts (N=21) the ORR was 66% and CR rate was 14%. After a median follow-up of 23 months. Median progression free survival (PFS) and overall survival (OS) were 4 months and not reached, respectively. 2-year OS was 53%. Two pts (PTCL, NOS and MF) completed the planned 6 cycles of therapy and remain in remission without consolidation at 30 months. Five pts were successfully bridged to SCT, all of whom remain alive and without progression. In pts treated at the MTD, the ORR was 89% and the CR rate was 22%. The multi-targeted therapy regimen RAdR is safe and can achieve CR after fixed duration in patients with relapsed refractory TCM. Toxicity is predominantly gastrointestinal and hematologic. Most patients do not achieve durable CR with RAdR alone, but it may be effective bridging therapy to consolidation. This study was supported by the Intramural Research Program of the NIH and was registered at Clinicaltrials.gov [NCT04447027]. Citation Format: Max Gordon, Milos Miljkovic, Samuel Ng, Rahul Lakhotia, Christopher Melani, Kevin Conlon, James Phelan, Bonita Bryant, Stefania Pittaluga, Elaine Jaffe, Louis Staudt, Wyndham Wilson, Mark Roschewski. A phase 1 study of romidepsin, azacitidine, dexamethasone, and lenalidomide (RAdR) for relapsed/refractory T-cell malignancies [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-007.

Analysis of polyfunctionality for enhanced BAFF-R CAR T-cell therapy for hematologic malignancies

AbstractChimeric antigen receptor (CAR) T-cell therapy has emerged as a promising immunotherapeutic strategy for eradicating human cancers. Their therapeutic success and durability of clinical responses hinges, in large part, on their functional capacity, including the ability of these engineered cells to simultaneously expand and persist after infusion into patients. CD19 CAR T-cell polyfunctionality, assessing the simultaneous functions of cytokine production, proliferation, and cytotoxicity has been reported to correlate with clinical outcomes. Assay optimization is potentially limited by the heterogeneous nature of CAR T-cell infusion products and target specificity. We optimized a single-cell platform for polyfunctionality using CAR T-cell products manufactured from healthy donors, engineered against a novel target, B-cell–activating factor receptor (BAFF-R) and validated the protocol using CD19 CAR T cells. We observed distinct qualitative differences between BAFF-R and CD19 CAR T cells relative to the proportions of stimulatory vs effector cytokines, based on target antigen density, and, generally, CD19 CAR T cells exhibited lower indices of polyfunctionality. Finally, we applied our assay to the autologous BAFF-R CAR T-cell product generated from the first patient with non-Hodgkin lymphoma treated in an ongoing clinical trial who had progressed after prior CD19 CAR T-cell therapy. We observed robust indicators of polyfunctionality, which correlated with successful CAR T-cell expansion after infusion and achievement of durable complete remission ongoing after 18 months. The precise identification of factors determining the role of BAFF-R CAR T-cell fitness in toxicity and clinical outcome will require the application of this robust assay in the analysis of additional treated patients. This trial was registered at www.ClinicalTrials.gov as #NCT05370430.

Immunological Checkpoint Blockade in Anal Squamous Cell Carcinoma: Dramatic Responses Tempered By Frequent Resistance.

Squamous cell carcinoma of the anus (SCCA) is an HPV-associated malignancy that has limited treatment options. Immunotherapy has expanded these options and here we review current and emerging immunotherapeutic approaches. Multiple studies of single-agent anti-PD1/PD-L1 immunotherapy have demonstrated a modest response rate of approximately 10% to 15%. While a minority of patients (~5%) with SCCA experience durable complete responses, most advanced SCCAs are resistant to anti-PD1/PD-L1 monotherapy. Given the need for more broadly effective immunotherapies, novel strategies, such as adaptive cell therapies and therapeutic vaccination, are being explored. To reduce the recurrence risk of localized high-risk SCCA, strategies combining immunotherapy with chemoradiation are also being investigated. While a small subset of patients with SCCA have prolonged responses to PD1-directed immunotherapy, the majority do not derive clinical benefit, and new immunotherapeutic strategies are needed. Better understanding of the immune microenvironment and predictive biomarkers could accelerate therapeutic advances.

PRGN-2012, a novel gorilla adenovirus-based immunotherapy, provides the first treatment that leads to complete and durable responses in recurrent respiratory papillomatosis patients.

LBA6015 Background: Recurrent respiratory papillomatosis (RRP) is a rare, neoplastic disorder caused by chronic infection with human papillomavirus (HPV) type 6 or 11. Significant morbidity can occur due to airway obstruction and, although rare, transformation into malignant cancer. There are no approved therapeutics. RRP is currently managed with frequent ablative procedures that can lead to irreversible laryngotracheal scarring and disability. PRGN-2012 is a gorilla adenovirus-based gene therapy/immunotherapy designed to generate HPV6/11-specific T cell immunity. The FDA has granted PRGN-2012 Breakthrough Therapy Designation for the treatment of RRP recognizing that this single arm study can serve as pivotal to support a licensing application. Methods: This pivotal trial (NCT04724980) evaluates the safety and efficacy of PRGN-2012 in patients with RRP requiring a minimum of 3 surgeries in the 12 months prior to treatment. Eligible patients received 4 subcutaneous (SC) injections of PRGN-2012 at dose level (DL) 1 (1x1011 Particle Units (PU) per injection; n=3) or DL2 (5x1011 PU per injection; n=35) over 12 weeks. The primary endpoint was the rate of complete response (CR), defined as no requirement for surgery in the 12 months following completion of treatment. Other key endpoints include duration of response, change in extent of papilloma growth (anatomic Derkay score) and vocal function. Results: PRGN-2012 was well-tolerated, with no serious adverse events, grade &gt; 2 treatment-related adverse events, or early treatment discontinuations. The most common adverse events were injection-site reaction, fatigue, chills, fever, and myalgia. PRGN-2012 treatment at DL2 significantly (p&lt;0.0001) decreased the requirement for surgery, with a median number of surgeries in the 12 month period decreasing from 4 (3-10) prior to treatment to 0 (0-7) surgeries post-treatment. Approximately 90% of patients experienced a decrease in the number of surgeries in the 12 months post-treatment compared to pre-treatment with PRGN-2012. The primary endpoint evaluation demonstrated a confirmed complete response in 17/31 (55%) of evaluable patients. The median duration of complete response has yet to be reached with a median follow up of 15 months (12 - 30) at the time of data cutoff (March 6, 2024). Additionally, PRGN-2012 treatment resulted in a significant reduction in Derkay score, improvement in vocal function and generation of HPV-specific immune responses. Conclusions: These data demonstrate the overall favorable safety profile and significant clinical benefit of PRGN-2012 in adult RRP patients. These findings support PRGN-2012 as a potential therapeutic option for this patient population where no FDA-approved therapeutics exist. Clinical trial information: NCT04724980 .