Severe Myelotoxicity Research Articles

Clinical management of patients diagnosed with acute myeloid leukemia treated with venetoclax in combination with hypomethylating agents after achieving a response: a real-life study.

Although there is an approved indication for venetoclax and hypomethylating agents (VenHMA) and its use in different AML settings will be expanded in the following years, the management of the adverse events (AEs) lacks of harmonized algorithms during treatment of these patients. We have studied the incidence of relevant AEs of 43 patients who achieved a response to VenHMA and its management. Median overall survival of our cohort was 19months. No patients discontinued treatment due to AEs after C3D1, Regarding severe AEs, high rates of grade 4 neutropenia (97.6%) and grade 4 thrombocytopenia (65.1%) were observed. Severe infectious AEs rate was 16%. Due to severe myelotoxicity, most patients required a progressive dose reduction of both venetoclax and hypomethylating agents during follow-up, being 87.8% at C6D1. Transfusional dependence rate was 91% and G-CSF was prescribed to 86% of the patients. Finally, there was not a significant difference in hemoglobin, platelets and absolute neutrophil count after achieving complete response comparing paired samples during follow-up, although cytopenia rate was high during initial follow-up. We conclude that dose reduction of VenHMA after achieving a response in patients diagnosed with AML is required in most patients and essential to avoid prolonged cytopenia-related adverse events and a rapid and standardized method on how to perform it might decrease the AEs rate.

Azacitidine combined with interferon-α for pre-emptive treatment of AML/MDS after allogeneic peripheral blood stem cell transplantation: A prospective phase II study.

This prospective clinical study aimed to evaluate the efficacy and safety of the pre-emptive treatment modality of azacitidine in combination with interferon-α (IFN-α) in AML/MDS patients post-transplantation. Forty-seven patients aged 17-62 were enrolled with 14 patients having completed the planned 12 cycles. Following initiation, 72.3% responded positively after the first cycle, peaking at 77.2% by the fifth cycle. Notably, 24 patients maintained sustained responses throughout a median follow-up of 1050 days (range, 866-1234). Overall survival, leukaemia-free survival and event-free survival probabilities at 3 years were 69.5%, 60.4% and 35.7% respectively. Cumulative incidences of relapse and non-relapse mortality were 36.5% and 4.3% respectively. Multivariate analysis identified that receiving pre-emptive treatment for fewer than six cycles and the absence of chronic graft-versus-host disease after intervention was significantly associated with poorer clinical outcomes. The combination of azacitidine with IFN-α was well-tolerated with no observed severe myelotoxicity, and the majority of adverse events were reversible and manageable. In conclusion, the use of azacitidine in conjunction with IFN-α as pre-emptive therapy is a safe and effective treatment to prevent disease progression in AML/MDS patients with MRD positivity post-allo-HSCT.

Impact of the homozygous mutation in Nudix hydrolase 15 on myelosuppression with 6-mercaptopurine in a European girl with acute lymphoblastic leukemia: A case report

A 6-year-old girl diagnosed with intermediate-risk acute lymphoblastic leukemia (ALL) presented with severe myelotoxicity and multiple infections during phase IB induction treatment with 6-mercaptopurine (6-MP). In the subsequent treatment phases, which included 6-MP, the patient continued to show bone marrow aplasia and neutropenia, necessitating numerous dose adjustments and interruptions. The recommended dose was eventually reduced to 5 %. A pharmacogenetic analysis, conducted in induction phase IB, detected three single-nucleotide polymorphisms (SNPs) of the thiopurine S-methyltransferase (TPMT) gene, and the phenotype of a normal metabolizer was observed. As a result of a second pharmacogenetic analysis, pathological polymorphisms were revealed in Nudix hydrolase 15 (NUDT15), which may explain the patient’s myelotoxicity. Hence, a pharmacogenetic analysis performed in advance would have been able to prevent her from suffering severe toxicity and/or treatment failure.

Bevacizumab, Irinotecan, and Biweekly Trifluridine/Tipiracil for Metastatic Colorectal Cancer: MODURATE, a Phase Ib Study.

In this phase Ib study MODURATE, we optimized the dosing schedule and tested the efficacy and safety of trifluridine/tipiracil, irinotecan, and bevacizumab in patients with metastatic colorectal cancer with fluoropyrimidine and oxaliplatin treatment failure. We included a dose escalation (3 + 3 design) and an expansion cohort. Patients were administered trifluridine/tipiracil (25-35 mg/m2 twice daily, days 1-5), irinotecan (150-180 mg/m2, day 1), and bevacizumab (5 mg/kg, day 1) every 2 weeks. The recommended phase II dose (RP2D) in the dose escalation cohort was administered to at least 15 patients in both cohorts combined. Twenty-eight patients were enrolled. Five dose-limiting toxicities were observed. RP2D was defined as trifluridine/tipiracil 35 mg/m2, irinotecan 150 mg/m2, and bevacizumab 5 mg/kg. Of 16 patients who received RP2D, 86% (14/16) experienced grade ≥3 neutropenia without febrile neutropenia. Dose reduction, delay, and discontinuation occurred in 94%, 94%, and 6% of patients, respectively. Three patients (19%) showed partial response and 5 had stable disease for >4 months, with a median progression-free and overall survival of 7.1 and 21.7 months, respectively. Biweekly trifluridine/tipiracil, irinotecan, and bevacizumab administration may have moderate antitumor activity with high risk of severe myelotoxicity in previously treated patients with metastatic colorectal cancer [UMIN Clinical Trials Registry (UMIN000019828) and Japan Registry of Clinical Trials (jRCTs041180028)].

Abstract 1548: CO-1008, an ADC program targeting leukemic progenitor and blast AML cells, but not normal hematopoetic progenitor cells

Abstract The overall survival of patients diagnosed with Acute Myeloid Leukemia (AML) remains low. While initial responses to therapy are favorable, the duration of response is short, and overcoming therapeutic resistance has proven difficult. The presence of chemoresistant leukemic stem cells (LSCs), among other mechanisms, has been implicated as a driver in the observed relapse. Antibody-drug conjugates (ADC) are targeted cancer therapeutics that leverage antigen specificity to deliver a potent cytotoxic payload. Recently, ADCs have shown promise in the clinic, but can also present safety and efficacy concerns. Mylotarg, an FDA approved CD33-directed ADC used to treat Acute Myeloid Leukemia, was the first ADC to be approved. The therapeutic is active against most AML tumors but can lead to severe myelotoxicity given the expression of CD33 on normal myeloid progenitor cells. We leveraged a pharmaco-pheno-multiomic analysis of primary AML tumors to uncover a previously unexplored target expressed on both LSCs and AML blasts, but not normal hematopoetic progenitor cells or other normal tissue. The target also showed capacity to rapidly internalize and has activity of well-established oncogenic kinases associated with expression. A novel monoclonal antibody (IgG1) with favorable binding and biophysical characteristics was established against this novel target and conjugated to a highly potent cytotoxic agent, creating a novel ADC. This ADC shows strong binding across AML tumors with effective internalization and highly potent killing of AML tumors. Citation Format: Garima Kaushik, Bandana Vishwakarma, Marina Bell, Kakajan Komurov. CO-1008, an ADC program targeting leukemic progenitor and blast AML cells, but not normal hematopoetic progenitor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1548.

Temozolomide-induced myelotoxicity and single nucleotide polymorphisms in the MGMT gene in patients with adult diffuse glioma: a single-institutional pharmacogenetic study.

Nearly 10% of patients with adult diffuse glioma develop clinically significant myelotoxicity while on temozolomide (TMZ) leading to treatment interruptions. This study aimed to assess single nucleotide polymorphisms (SNPs) in the O6-methylguanine-DNA methyltransferase (MGMT) gene in adults with biopsy-proven diffuse glioma who develop TMZ-induced myelotoxicity and correlate their presence with severity and duration of such toxicity. This study assessed 33 adults treated with TMZ for diffuse glioma who developed ≥ grade 2 thrombocytopenia and/or ≥ grade 3 neutropenia. Genomic DNA was extracted from peripheral blood cells for MGMT SNP analysis after written informed consent. TMZ-induced severe myelotoxicity (≥ grade 3) was correlated with three specified SNPs commonly seen in the MGMT gene (L84F, I143V/K178R) using chi-square test or Fischer's exact test as appropriate. Of the 33 adults, 24 (72.7%) experienced ≥ grade 3 thrombocytopenia and/or neutropenia, while 9 (27.3%) developed grade 2 thrombocytopenia only. The variant T allele of L84F was expressed in 28.7% (19/66) of analyzed alleles, which was substantially higher than previously reported for South Asian ancestry. The variant G allele of I143V/K178R was expressed in 9.3% (6/64) of analyzed alleles. Of which 3 patients showed statistically significant association with prolonged myelosuppression for > 2months (p = 0.03). No significant correlation was established between the mentioned SNPs and severe myelotoxicity. There is substantially higher frequency of variant T allele (L84F) in Indian patients than previously reported for South Asians. The presence of specific SNPs in the MGMT gene correlates with prolonged duration but not severity of TMZ-induced myelotoxicity.

Efficacy and Toxicity Analysis of Capecitabine and Temozolomide in Neuroendocrine Neoplasms.

The capecitabine/temozolomide (CAPTEM) regimen has significant activity in advanced neuroendocrine tumors (NETs). Questions exist regarding activity in pancreatic versus nonpancreatic NETs, risk of opportunistic infections, long-term myelotoxicity, and safety of prolonged treatment duration. Analysis of large patient cohorts is needed for the evaluation of rare toxicities and assessment of risk factors. We conducted a retrospective study of all patients with advanced NETs seen at Moffitt Cancer Center between January 2008 and June 2019 who received treatment with CAPTEM. A total of 462 patients were eligible. The objective radiographic response rate was 46%, and the disease control rate was 81%. Median progression-free survival (PFS) was 18 months (95% CI, 14.0-21.9 months) and median overall survival was 51 months (95% CI, 42.8-59.2 months): 62 months in well-differentiated NETs versus 14 months in poorly differentiated neuroendocrine carcinomas (P<.0001). Patients with primary pancreatic tumors had the highest partial response rates and longest median PFS. Incidences of grade 4 thrombocytopenia and neutropenia were 7% and 3%, respectively, and substantially higher in women than men (P=.02 and P=.004, respectively). Only 1 case (0.2%) of suspected Pneumocystis pneumonia (PCP) was observed in a patient receiving corticosteroids. Three patients developed myelodysplastic disease, all of whom had received prior peptide receptor radiotherapy (PRRT). There were no acute treatment-related deaths; 1 patient died 2 months after a thrombocytopenic bleed. The CAPTEM regimen is exceptionally safe. Efficacy is particularly robust in well-differentiated pancreatic NETs. Severe myelotoxicity is rare; the risk of grade 4 cytopenias is significantly increased in women, and therefore sex-based dosing should be considered. There were no cases of myelodysplastic syndromes, except among patients who had received PRRT, a known risk factor. The risk of PCP is negligible.

Germline polymorphisms in MGMT associated with temozolomide-related myelotoxicity risk in patients with glioblastoma treated on NRG Oncology/RTOG 0825.

BackgroundWe sought to identify clinical and genetic predictors of temozolomide-related myelotoxicity among patients receiving therapy for glioblastoma.MethodsPatients (n = 591) receiving therapy on NRG Oncology/RTOG 0825 were included in the analysis. Cases were patients with severe myelotoxicity (grade 3 and higher leukopenia, neutropenia, and/or thrombocytopenia); controls were patients without such toxicity. A risk-prediction model was built and cross-validated by logistic regression using only clinical variables and extended using polymorphisms associated with myelotoxicity.Results23% of patients developed myelotoxicity (n = 134). This toxicity was first reported during the concurrent phase of therapy for 56 patients; 30 stopped treatment due to toxicity. Among those who continued therapy (n = 26), 11 experienced myelotoxicity again. The final multivariable clinical factor model included treatment arm, gender, and anticonvulsant status and had low prediction accuracy (area under the curve [AUC] = 0.672). The final extended risk prediction model including four polymorphisms in MGMT had better prediction (AUC = 0.827). Receiving combination chemotherapy (OR, 1.82; 95% CI, 1.02–3.27) and being female (OR, 4.45; 95% CI, 2.45–8.08) significantly increased myelotoxicity risk. For each additional minor allele in the polymorphisms, the risk increased by 64% (OR, 1.64; 95% CI, 1.43–1.89).ConclusionsMyelotoxicity during concurrent chemoradiation with temozolomide is an uncommon but serious event, often leading to treatment cessation. Successful prediction of toxicity may lead to more cost-effective individualized monitoring of at-risk subjects. The addition of genetic factors greatly enhanced our ability to predict toxicity among a group of similarly treated glioblastoma patients.

Thymus Subset Alterations Accompanying Concomitant Tumor Immunity Mimics Phenotypic Patterns of Cytotoxic Drug Doxorubicin.

Concomitant immunity (CIM) is a phenomenon that elicits an antitumor response not sufficient enough to destroy the primary tumor but prevents a secondary implant from growing and spreading. This study aimed to develop a method of identification of serum tumoricidal factors released into circulation during CIM and to compare the CIM-related effect to the effect elicited by the cytotoxic drug doxorubicin. SL2 tumor-bearing mice were studied at three time points - day 4, day 7, and day 11 following i.p. 5×105 cell implantation. Hematological effects and thymocyte immunophenotyping (CD4/CD8) data were compared to the effects induced by intravenous 10 mg/kg doxorubicin (DOX) administration to intact DBA 2 mice. The level of plasma colony stimulating factor-granulocyte macrophage (CSF-GM) was evaluated by ELISA. Identical thymus histopathology and an extent of double-positive CD4+CD8+ subset depletion was found in day 11 tumor-bearing mice (TBM-11) and in DOX-administered animals. TBM-11 exhibited a leukemoid reaction with an increase in monocyte and granulocyte counts. Conversely, DOX administration was followed by severe leukocytopenia at the 72-h time point. No increase in CSF-GM was observed in mice with or without a leukemoid reaction. The complexity of CIM can be examined by tracking alterations in the most fragile cortical CD8+CD4+ double positive population. Thymocyte apoptosis induced by DOX and TBM-11 might be associated with different mechanisms. TBM-11 did not exhibit severe myelotoxicity as DOX did. CIM-related serum factors can be assessed and screened via thymocyte subset analysis.

Chronic lymphocytic leukaemia/small lymphocytic lymphoma treatment with rituximab and high-dose methylprednisolone, revisited.

High‐dose methylprednisolone plus rituximab (R‐HDMP) is a useful treatment in chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) patients unfit for chemo‐immunotherapy and has proven its utility on the treatment of CLL/SLL complicated by auto‐immune cytopenias. We performed a retrospective, single‐centre study, of CLL/SLL patients treated with R‐HDMP for 9 years. Thirty‐nine patients were included, median age at time of treatment was 77 years. Most patients had stage Rai III/IV and Binet C disease. Twenty‐eight patients had relapsed/refractory disease at time of treatment with a median of 1 previous line of therapy; 53.8% had prior exposure to fludarabine and 25% to rituximab. Grade 3–4 neutropenia and thrombocytopenia were recorded in 10.2% and 17.9% patients, respectively. While on treatment, 51.3% had documented infectious complications, but no other non‐haematological toxicities grades 3–4 were identified. Overall response rate was 64%. Median overall survival and progression‐free survival were 24 and 13 months, respectively. Twenty four patients relapsed and 16 received another line of treatment after R‐HDMP, with median time to next treatment of 13.5 months. Thirteen out of the 24 patients improved performance status and were subsequently considered fit for chemo‐immunotherapy. R‐HDMP is a valuable option for elderly and frail patients, with low risk of severe myelotoxicity and other severe adverse events. It was shown to work as a bridge to other lines of treatment, including chemo‐immunotherapy.

Safety of Emapalumab in Pediatric Patients with Primary Hemophagocytic Lymphohistiocytosis (HLH): Relationship to Treatment Exposure

▪Introduction: Primary hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening, immune disorder characterized by a hyperinflammatory state in which interferon gamma (IFNγ) is considered a key cytokine. The treatment goal of primary HLH is to stabilize the disease by controlling the associated hyperinflammation to bring patients to allogeneic hematopoietic stem cell transplantation (HSCT), the only curative therapy so far. Current conventional therapy for HLH is based on immunochemotherapies, namely etoposide and glucocorticoids; this treatment, however, is associated with opportunistic infections and severe myelotoxicity. Emapalumab, a fully human, anti-IFNγ monoclonal antibody that neutralizes IFNγ, is the only FDA-approved treatment for primary HLH patients with refractory, recurrent or progressive disease, or intolerance to conventional HLH therapy. In patients with primary HLH, the pharmacokinetics (PK) of emapalumab is highly influenced by body weight, and also by IFNγ production due to target-mediated drug disposition. In the pivotal trial (Locatelli et al NEJM 2020;382:1811-22), treatment of primary HLH patients with emapalumab was associated with a favorable safety and tolerability profile, with no unexpected safety concerns.Objective: To describe prespecified exploratory exposure-safety analyses that were performed on data from patients with primary HLH receiving emapalumab in the pivotal trial.Methods: Data from a multicenter, open-label, pivotal phase 2/3 study (NCT01818492) and its long-term follow-up study (NCT02069899) were included in this analysis. The safety of emapalumab was assessed in 34 patients (27 treatment experienced; 7 treatment naïve) with active primary HLH. Emapalumab was initiated at a dose of 1 mg/kg administered intravenously every 3 days, on a background of dexamethasone 5-10 mg/kg/day. Subsequent doses could be increased to 3, 6 and 10 mg/kg, if required, based on predefined laboratory and clinical response parameters. Treatment duration was up to 8 weeks, with possible shortening to a minimum of 4 weeks, or extension up to time of transplantation if needed. Exploratory graphical analyses were performed to determine the incidence of adverse events (AEs) as a function of the exposure parameters at the time of the AE. The relationship between emapalumab exposure and the incidence of treatment-emergent AEs, serious AEs, severe AEs, and AEs related to infections and infusion-related reactions (IRRs) was explored by logistic regression analyses. Selected parameters of renal (creatine clearance [CRCL]) and liver (total bilirubin [TBIL] and alanine aminotransferase [ALT]) function were explored graphically. Exposure parameters were obtained from the population PK/pharmacodynamic (PD) data file that was used for the population PK and PK/PD analyses. Observed individual concentration-time data were used to derive the individual exposure parameters as a function of time. The analyses considered AEs that emerged after the start of the first infusion until last infusion and prior to initiation of HSCT conditioning.Results: Exploratory graphical exposure-safety analyses did not reveal any apparent relationship between the number of AEs and exposure to emapalumab. Logistic exposure-safety regression analyses using the observed exposure to emapalumab at the time of an AE for patients experiencing an event and the highest observed exposure to emapalumab for those patients experiencing no AE, indicated that the incidence of AEs did not increase as a function of increasing emapalumab concentration. In fact, a statistically significant decrease in the incidence of severe AEs and the incidence of AEs related to IRRs was observed. No multivariate effects were identified in the multivariate regression analyses. No clear trend was observed for TBIL, ALT or CRCL as a function of the duration of emapalumab treatment. The exposure of emapalumab did not appear to influence the levels of TBIL, ALT or CRCL in individual patients during treatment.Conclusion: In this study, the exposure-safety evaluation did not reveal any significant relationships between exposure to emapalumab and observed incidence rates of AEs, serious AEs, infections, or IRRs. These findings support the primary evidence of a favorable benefit-risk profile of emapalumab across the dose range used in this fragile patient population. DisclosuresJordan: Sobi: Consultancy. Locatelli: Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Miltenyi: Speakers Bureau; Medac: Speakers Bureau; Jazz Pharamceutical: Speakers Bureau; Takeda: Speakers Bureau. Jacqmin: Sobi: Consultancy. Laveille: Sobi: Consultancy. Snoeck: Sobi: Consultancy. de Min: Sobi: Consultancy, Ended employment in the past 24 months.

Heterozygous NUDT15 Gene Polymorphism Would Not Associate with the Severity of 6-Mercaptopurine Side Effects in Early Intensification Therapy for Childhood Acute Lymphoblastic Leukemia

BackgroundIn the treatment of childhood acute lymphoblastic leukemia (ALL), 6-mercaptopurine (6-MP) is essential for early intensification and maintenance therapy. Recently, it has been reported that a gene polymorphism of nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15) rs116855232 is associated with the 6-MP induced severe myelotoxicity. Since the NUDT15 rs116855232 polymorphism is relatively common in East Asian and Hispanic populations, it is important to evaluate the association between the polymorphism and 6-MP for determining the dose of effective therapy and avoiding the side effect in Japan. However, there are few reports on the association between NUDT15 polymorphisms and the therapeutic efficacy or side effects of 6-MP in the early intensification; most previous reports focused on the maintenance therapy so far. The purpose of this study is to clarify the association between NUDT15 polymorphism and the actual treatment status with 6-MP or its side effects, therefore to contribute to the effective and safe treatment of childhood ALL in Japan.MethodsTwenty-four patients with ALL who received early intensification therapy according to the JPLSG ALL-B12 or JPLSG ALL-T11 protocol at the Department of Pediatrics, Hokkaido University Hospital, between April 2013 and May 2021 were included in the study. We retrospectively collected the clinical and laboratory data from the clinical records. And we also performed the sequence analysis of the exon 1 and 3 in NUDT15 geneResultsGenetic analysis of NUDT15 showed no nucleotide changes other than rs116855232. Twenty patients were CC (wild-type), 4 patients were CT (heterozygous-variant), and 0 patients were TT (homozygous-variant). Of the 4 patients with heterozygous-variant, one patient received a reduced dose of 6-MP because of early onset myelotoxicity during early intensification therapy. In this patient, the total dose of 6-MP was 70% of the standard dose. All the 24 patients showed myelotoxicity and hepatotoxicity during early intensification therapy. Correlations between NUDT15 haplotype and side effects as myelotoxicity and hepatotoxicity were not significant.DiscussionIn the heterozygous-variant of NUDT15 rs116855232, the incidence and degree of myelotoxicity and hepatotoxicity during early intensification therapy did not differ from the wild-type. The international consortium (Clinical Pharmacogenetics Implementation Consortium Guideline, 2018) recommends that the dose of 6-MP should be reduced to 10mg/m2/day in patients with homozygous variant of NUDT15, however, the reduction of the starting dose of 6-MP in those with heterozygous variant is not recommended. Of note, these recommendations were made based on the data in the maintenance therapy. Our study suggests that the reduction of the starting dose may not be necessary in children with heterozygous variant. The NUDT15 rs116855232 polymorphism is common in Japan, with 10% of heterozygotes and 1.1% of homozygotes. In future study, a larger study on the association between NUDT15 polymorphism and treatment outcome including side effects in the early intensification is needed in East Asia to confirm the results of our study. DisclosuresNo relevant conflicts of interest to declare.

NUDT15 c.415C>T Polymorphism Predicts 6-MP Induced Early Myelotoxicity in Patients with Acute Lymphoblastic Leukemia Undergoing Maintenance Therapy.

PurposeSevere myelosuppression in patients with acute lymphoblastic leukemia (ALL) undergoing 6-MP-based maintenance therapy is attributed to TPMT gene polymorphisms, which is rare in Asian populations. This study aims to evaluate the role of selected polymorphisms in NUDT15, ITPA, and MRP4 genes in addition to TPMT in predicting 6-MP intolerance during ALL maintenance therapy.Patients and MethodsWe screened for the presence of NUDT15*3 (c.415 C>T, rs116855232); MRP4 c.2269 C>T (rs3765534), ITPA c.94 C>A (rs1127354) polymorphisms in addition to TPMT *2 (rs1800462), *3A (*3B and *3C; rs1800460 and rs1142345) in ALL patients with documented severe neutropenia (cohort-1; n=42). These polymorphisms were then screened in a prospective cohort of ALL patients (cohort-2; n=133) and compared with 6-MP dose reduction, early/late myelotoxicity.ResultsNineteen (45%) patients in cohort-1 and 18 (14%) in cohort-2 had NUDT15 c.415 C>T variant while 4 (3%) patients in cohort-2 had TPMT*3C variant. Five (12%) in cohort-1 and 30 (24%) in cohort-2 had ITPA c.94 C>A variant while 9 (22%) and 15 (12%) had MRP4 c.2269 C>T variant in cohorts-1 and 2, respectively. All in cohort-1 and 36 (27%) in cohort-2 had severe myelotoxicity. Twenty-eight patients (66.6%) in cohort-1 and 40 (30%) patients in cohort-2 had significant 6-MP dose reduction. NUDT15 c.415 C>T variant explained severe myelotoxicity in 63% and 33% in cohort 1 and 2. TPMT*3C and ITPA c.94 C>A variants also explained myelotoxicity in cohort-2 (Median ANC: 376 vs 1014 mm3; p=0.04 and 776 vs 1023 mm3; p=0.04 respectively). NUDT15 c.415 C>T polymorphism explained significant myelotoxicity (507 vs 1298 mm3; p<0.0001) in the multivariate analysis as well (β=−0.314, p<0.0001).ConclusionNUDT15 c.415 C>T (15*3), TPMT*3C, as well as ITPA c.94 C>A and MRP4 c.2269 C>T polymorphisms explain hematotoxicities. Preemptive genotype-based (NUDT15*3, TPMT, ITPA c.94 C>A) 6-MP dosing could improve the outcome after maintenance therapy.

Cost-effectiveness analysis of genotype screening and therapeutic drug monitoring in patients with inflammatory bowel disease treated with azathioprine therapy: a Chinese healthcare perspective using real-world data.

BackgroundThis study aimed to analyze the cost-effectiveness of combining screening for thiopurine methyl transferase (TPMT) and nucleotide triphosphate diphosphatase (NUDT15) defective alleles with therapeutic drug monitoring (TDM) in Chinese patients with inflammatory bowel disease (IBD) treated with azathioprine (AZA).MethodsWe evaluated the cost-effectiveness of combining screening for NUDT15 and TPMT deficiency with TDM in patients receiving AZA treatment over a 1-year horizon by developing a decision tree model. Real-world data and published literature were used to derive model inputs. The model’s primary outcomes included quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). One-way and probabilistic sensitivity analyses were used to address uncertainty.ResultsCompared to NUDT15 genotyping, the combined TPMT/NUDT15 genotyping strategy cost an additional $13.83, yielding an ICER of $3,929.54/QALY, which was under the willingness-to-pay level of $30,425 per QALY in China. Compared to strategies with singular TPMT genotyping or no genotyping, the combined TPMT/NUDT15 genotyping strategy gained 0.00406 and 0.00782 QALYs and reduced the cost by $25.15 and $99.06, respectively. Additionally, incorporating TDM of AZA was more effective and less expensive than strategies without TDM. One-way sensitivity analysis revealed the expense attached to severe myelotoxicity to be the factor with the greatest influence in the present research. The application of the combined genotype screening strategy with TDM of AZA treatment was found to have a 91.7% chance of being cost-effective.ConclusionsFor Chinese patients with IBD who receive an AZA regimen, a strategy involving combined NUDT15/TPMT genotype screening prior to treatment initiation and incorporating TDM for treatment management is cost-effective compared to strategies involving genotyping of NUDT15 or TPMT alone or genotyping without TDM.

Adjuvant chemotherapy after severe myelotoxicity during chemoradiation phase in malignant gliomas. Is it feasibile? Results fromAINO study (Italian Association for Neuro-Oncology).

Malignant gliomas (MG) are aggressive brain tumours in adults. The standard of care is concurrent radiation plus temozolomide (TMZ) [chemo-radiotherapy (CRT)] followed by TMZ maintenance up to 6months. TMZ is considered to have a low toxicity profile, but several studies reported occurrence of severe myelosuppression, especially during the concomitant phase. Toxicity may be prolonged, thustreatment should be discontinued. To evaluate the risk of recurrente myelotoxicity during adjuvant chemotherapy (CT) in patients who recovered fromsevere myelotoxicity during CRT. We retrospectively collected data on patients with MG who developed and recovered from severe myelotoxicity during CRT from eight Italian neuro-oncology centers. We included 87 patients. Histology was Glioblastoma (GBM) in 78 patients (89.7%); 60% of patients were female. After myelotoxicity recovery, 54 (62%) received treatment. The majority of them (82%, n = 44) received adjuvant TMZ and 18% (n = 10) others treatments. Out of 44 patients who received adjuvant TMZ, 34% experienced the re-occurrence of grade 3-4 myelotoxicity which required permanent CT discontinuation in 6 (13%) cases. Patients who received TMZ or other treatments had longer overall (OS) (adjusted HR 0.46, p = 0.008) and progression free survival (PFS) (adjusted HR 0.57, p = 0.034) than those who remained untreated. Our study suggests that after severe myelotoxicity the majority of patients received treatment, particularly with TMZ. Only a fraction of patients experienced toxicity recurrence, suggesting that TMZ is well tolerated and had an impact on PFS and OS.

Toxicity analysis of capecitabine/temozolomide in NETs.

4614 Background: The capecitabine/temozolomide regimen has significant activity in advanced NETs. Concerns exist regarding risk of opportunistic infections and long-term myelotoxicity. Analysis of large patient cohorts is needed for evaluation of rare toxicities and for assessment of risk factors. Methods: Retrospective study of all patients with advanced neuroendocrine neoplasms seen at the Moffitt Cancer Center between 1/2008 and 6/2019 who received treatment with CAPTEM. Patients who initiated treatment at outside institutions were included if they were prescribed treatment at appropriate doses and if complete records were available. Results: 462 patients met eligibility criteria for evaluation: 210 (45%) females and 252 (55%) males with a median age of 59. Median starting doses of CAP and TEM were 658mg/m2 and 180mg/m2 respectively. Median duration on treatment was 8 months. 25% of patients required a dose reduction and 16% discontinued due to toxicity of any grade. Incidence of grade 4 thrombocytopenia was 7%: 10% in females and 5% in males (p = 0.02). 4 cases were complicated by bleeding (0.8%). Incidence of grade 4 neutropenia was 3%: 5% in females and 1% in males (p = 0.004). Incidence of grade 4 lymphopenia was 2%. Only one case (0.2%) of suspected PCP was observed in a patient taking corticosteroids. There were 5 cases of herpes zoster and no other opportunistic infections. 3 patients developed myelodysplastic or myeloproliferative disease, all of whom had also received prior PRRT with Lutetium-Dotatate. There were no acute treatment related deaths, although one patient died 2 months after a thrombocytopenic bleed. Conclusions: Severe myelotoxicity is rare, but risks of grade 4 thrombocytopenia and neutropenia are significantly increased in females compared to males. Gender-based dosing should be considered. While alkylating agents are often associated with MDS, there were no cases except among patients who also had received PRRT, a known risk factor. PCP is not a significant risk with this regimen in patients not concurrently on corticosteroids.

INNV-14. ADJUVANT CHEMOTHERAPY AFTER SEVERE MYELOTOXICITY DURING TEMOZOLOMIDE CHEMORADIATION IN GLIOMAS. IT IS FEASIBILE?

Abstract INTRODUCTION Malignant gliomas are aggressive primitive brain tumor in adults. Today, the standard of care is Temozolomide (TMZ) administered daily with radiation therapy, followed by adjuvant TMZ. TMZ treatment has been considered to have a low toxicity profile. However, during concomitant treatment some patient may develop a severe myelosuppression. This toxicity may be in some cases prolonged and lead to treatment discontinuation. METHODS We have retrospectively collected data from 5 Italian neuro-oncological centers, about glioma patients who developed severe and prolonged hematological toxicity during concomitant chemoradiotherapy with TMZ. The purpose of this study is to evaluate: percentage of patients receiving adjuvant chemotherapy after severe myelotoxicity; rate of toxicity observed during adjuvant chemotherapy. RESULTS 54 glioma patients who developed myelosuppression of grade 3 or 4 were considered. Histology was Glioblastoma in 45 patients (83%); 63% of patients were female. Myelotoxicity during concomitant phase occurred at a median of 4 weeks (range 1–8) from the start of treatment. After recovery of myelotoxicity 19 patients did not received any treatment while 35 (65%) were treated with chemotherapy (28 received standard TMZ, one TMZ with metronomic schedule, 2 lomustine and 4 other agents). Among patients treated with TMZ, 13 patients presented hematological toxicity grade 3–4 which required treatment discontinuation in 7 cases (20%). CONCLUSION the results of our study show that 80% of glioma patients presenting severe myelotoxicity during concomitant radiochemotherapy may be treated with maintenance TMZ after recovery of myelosuppression.

P14.83 Adjuvant chemotherapy after severe myelotoxicity during temozolomide chemoradiation in gliomas. It is feasibile? The talian Multicentric Study (AINO)

Abstract BACKGROUND Malignant gliomas are aggressive primitive brain tumor in adults. Today, the standard of care is Temozolomide (TMZ) administered daily with radiation therapy, followed by adjuvant TMZ. TMZ treatment has been considered to have a low toxicity profile. However, during concomitant treatment some patient may develop a severe myelosuppression. This toxicity may be in some cases prolonged and lead to treatment discontinuation. MATERIAL AND METHODS We have retrospectively collected data from 5 italian neuro-oncological centers, about glioma patients who developed severe and prolonged hematological toxicity during concomitant chemoradiotherapy with TMZ. The purpouse of this study is to evaluate: percentage of patients receiving adjuvant chemotherapy after severe myelotoxicity; rate of toxicity observed during adjuvant chemotherapy. RESULTS 54 glioma patients who developed myelosuppression of grade 3 or 4 were considered. Hystology was Glioblastoma in 45 patients (83%); 63% of patients were female. Myelotoxicity during concomitant phase occurred at a median of 4 weeks (range 1–8) from the start of treatment.After recovery of myelotoxicity 19 patients did not received any treatment while 35 (65%) were treated with chemotherapy (28 received standard TMZ, one TMZ with metronomic schedule, 2 lomustine and 4 other agents). Among patients treated with TMZ, 13 patients presented hematological toxicity grade 3–4 which required treatment discontinuation in 7 cases (20%). CONCLUSION we observed that 80 % of glioma patients presenting severe myelotoxicity during concomitant radiochemotherapy may be treated with maintenance TMZ after blood value recovery.

Phase II trial with sequential clofarabine and cyclophosphamide for refractory and relapsed philadelphia-negative adult acute lymphoblastic leukemia. Results of the GIMEMA LAL 1610 protocol

Clofarabine (CLO) and cyclophosphamide (CY) combinations were tested in late stage refractory/relapsed (R/R) acute lymphoblastic leukemia (ALL) with disappointing results and high-grade toxicity. We designed a sequential 5-day combination of CLO 40 mg/m2/d plus CY 400 mg/m2/d as first salvage for Philadelphia-negative ALL patients refractory or relapsed until 24 months from complete remission (CR). Primary endpoint was an overall response rate (ORR) ≥ 40%. Among 26 study patients (median age 40.5 years) ORR was 57.6% (CR with complete [n = 8] or incomplete [n = 7] hematologic recovery). Despite severe myelotoxicity, no dose-limiting toxicity suggested de-intensification of CLO schedule. With a median follow-up of 17.0 months, median and 1-year overall and disease-free survival were 6.5 months and 28.6%, and 3.7 months and 28.1%, respectively. This association was tolerable and more effective in patients younger than 40 years with B-precursor ALL, longer first CR, not previously transplanted and achieving CR with full hematological recovery.

Modeling the Outcome of Systematic TPMT Genotyping or Phenotyping Before Azathioprine Prescription: A Cost-Effectiveness Analysis.

Thiopurine S-methyltransferase (TPMT) testing, either by genotyping or phenotyping, can reduce the incidence of adverse severe myelotoxicity episodes induced by azathioprine. The comparative cost-effectiveness of TPMT genotyping and phenotyping are not known. Our aim was to assess the cost-effectiveness of phenotyping-based dosing of TPMT activity, genotyping-based screening and no screening (reference) for patients treated with azathioprine. A decision tree was built to compare the conventional weight-based dosing strategy with phenotyping and with genotyping using a micro-simulation model of patients with inflammatory bowel disease from the perspective of the French health care system. The time horizon was set up as 1year. Only direct medical costs were used. Data used were obtained from previous reports, except for screening test and admission costs, which were from real cases. The main outcome was the cost-effectiveness ratios, with an effectiveness criterion of one averted severe myelotoxicity episode. The total expected cost of the no screening strategy was €409/patient, the total expected cost of the phenotyping strategy was €427/patient, and the total expected cost of the genotyping strategy was €476/patient. The incremental cost-effectiveness ratio was €2602/severe myelotoxicity averted in using the phenotyping strategy, and €11,244/severe myelotoxicity averted in the genotyping strategy compared to the no screening strategy. At prevalence rates of severe myelotoxicity > 1%, phenotyping dominated genotyping and conventional strategies. The phenotype-based strategy to screen for TPMT deficiency dominates (cheaper and more effective) the genotype-based screening strategy in France. Phenotype-based screening dominates no screening in populations with a prevalence of severe myelosuppression due to azathioprine of > 1%.