Citations

Introduction: BCMA-directed CAR-T and Bispecific T-cell engager (BiTE) therapies have shown remarkable overall response rates in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM). This has led to the approval of idecabtagene vicleucel, ciltacabtagene autoleucel and teclistamab by the FDA, EMA and other regulatory agencies. We performed a global survey on accessibility, practice patterns, and toxicity management of commercially available CAR-T and BiTE therapies. Methods: An online survey was completed by clinicians attending the International Myeloma Society's Immune Effector Cell Therapies in Multiple Myeloma Workshop, in-person or virtually, made available for 30 days after the meeting held in March 2023, Boston, MA. Results: 87 clinicians from 16 countries completed the survey, most practicing in an academic practice (86%) and in an urban environment (89%). Sixty-four percent of the respondents practice in North America followed by Europe (25.3%) including Germany, United Kingdom, Ireland, Italy, Netherlands, Spain, France, Greece, and Cyprus, and 6.9% from Asia and 3.4% from Australia. Seventy-seven percent reported CAR-T cell therapy was approved in their country with 44.8% treating 1-5 patients and 14.9% treating >5 patients per month; 67% reported BiTE therapy was approved in their country with 14.9% treating >5 patients per month. Of evaluable responses (n = 40), 62% administered CAR-T therapy inpatient and 15% administered CAR-T therapy outpatient ≥ 50% of the time. Length of time between decision to treat with CAR-T therapy to infusion was 6-12 weeks for 42% of responders and <6 weeks for only 20%. Most (75%) reported inpatient administration of BiTE therapy step-up dosing; 17.5% reported outpatient step-up dosing administered ≥ 50% of the time. Use of institutional or practice SOPs for CAR-T and BiTE therapy patient selection was reported by 85% and 58%, respectively, with the factors influencing SOP outlined in Table 1. Of available CAR-T therapies, 53% prefer cilta-cel and 23% reported CAR-T therapy preference depended most on patients' co-morbidities/frailty (89%), timing of next available apheresis (67%), age (56%), CNS disease (44%) and other factors. Maintenance therapy after CAR-T therapy was reportedly used by 25% and 5% of respondents in 1-10% and 11-50% of their patients, respectively, to “maintain level of response achieved” (50%) or “achieve a deeper level of response” (25%). About half (43%) of the respondents reported using an SOP or particular criteria for secondary Hemophagocytic Lympho-Histiocytosis/Macrophage Activation Syndrome/CAR-related-HLH (sHLH/MAS/CarHLH) management that varied between the use of ASTCT Working Group IEC associated HLH-like syndrome Criteria (47%) (Hines 2023), CARTOX HLH Criteria (24%) (Neelapu 2017) and HLH-2004 criteria (6%). Tocilizumab was used as cytokine release syndrome (CRS) prophylaxis only by one responder. Keppra neurologic prophylaxis was used by 47.5% and 15% of responders for CAR-T and BiTE therapy, respectively. Delayed neurotoxicity with CAR-T was reported in 1-5% of patients by 57.5% of responders and 6-10% of patients by 15% of responders; most common manifestations were other movement/neuromuscular disorder (62%), nerve palsy (55%), and Parkinsonism (45%). Infectious prophylaxis was used to protect against HSV (92.5%), PJP (90%), bacterial pathogens (55%), fungal pathogens (60%), and IVIG (77.5%). However, criteria for infectious prophylaxis use varies widely incorporating IgG levels, infectious history, CD4+ count, B-cell aplasia and cytopenias (48.1 - 88.9%). Most respondents (46.3 - 86.5%) reported completing an infectious work-up including CMV, EBV, Hep B/C, and HIV ( Table 2). Conclusions: Trends of CAR-T and BiTE therapy use and patterns of concurrent prophylactic and supportive care in MM vary widely among academic centers across the globe, demonstrating a need for further understanding of toxicity pathogenesis, toxicity management and consistent guidelines. This survey also demonstrates the great unmet need for access beyond urban centers among the international myeloma community. Prospective studies and claims data analysis should be utilized to evaluate the longitudinal cost of care, quality of life, duration of response and management of infectious disease, neurological or related complications of CAR-T and bispecific TCE therapies.

Introduction: Preclinical studies have suggested synergism between lenalidomide (LEN) and ibrutinib (IBR) in multiple myeloma (MM). Both downregulate IRF4, a master transcriptional factor that regulates myeloma cell survival. Single agent oral IBR combined with dexamethasone proved well tolerated and active in advanced, steroid refractory relapsed MM as part of a large Phase1/2 study in 60 patients, with durable stabilization and minimal response seen in most evaluable patients (Richardson PG et al, BJH 2018). LEN is considered a standard of care in newly diagnosed MM, as maintenance and in relapsed disease, and a backbone of oral therapy in the MM treatment paradigm (Laubach JP et al, Leukemia 2016). Methods: We therefore conducted a 3+3 phase I trial to determine the maximum tolerated dose (MTD) of IBR in combination with LEN + dexamethasone (DEX) in patients with relapsed/refractory (RR) MM who had at least 2 prior lines of therapy. Three dose levels (DL) were planned. Cycle length was 28 days. IBR was administered orally daily at 560mg on DL1-2 and 840mg on DL3, LEN orally days 1-21 at 15mg on DL1 and 25mg on DL2-3, and DEX orally days 1, 8, 15, and 22 at 40 mg if age < 75 or 20 mg if ≥75 for DL1-3. Patients with GFR ≥ 30 and < 60 were treated according to manufacturer's instructions with lenalidomide dosed at 10mg/d. Dose limiting toxicities (DLT) included grade 4 thrombocytopenia; grade 4 neutropenia lasting more than 5 days or febrile neutropenia; grade 4 nausea, vomiting or diarrhea; grade 3 thrombocytopenia with bleeding or platelet transfusion; grade 3-4 hyperglycemia or thrombotic/embolic event, treatment delays ≥ 21 days for toxicity; and treatment related death. Due to changes in standard of care during the study, eligibility was modified to allow the enrollment of patients with RRMM who had at least 1 prior line of therapy. Response was assessed using IMWG/Uniform Criteria. Results: Fourteen patients (DL1-6 pts; DL2-3 pts; DL3-5 pts) registered to the study from March 2019 to May 2023, prior to its closure due to slow accrual. One patient on DL3 cancelled participation prior to start of treatment due to disease progression (PD). The remaining 13 patients are included in summary of toxicities and response but 2 patients on DL3 are excluded from determination of MTD due to discontinuing cycle 1 treatment due to COVID and receiving 280 mg/day of IBR instead of assigned 840 mg/day dose during cycle 1, respectfully. Twelve patients were evaluable for response. The median number of prior lines of therapy was 3 (range: 2-9), reflecting a heavily pretreated relapsed and refractory population. One of the 6 patient on DL1 developed a DLT, grade 3 non-viral hepatitis. None of the 3 patients on DL2 or the 2 patients on DL3 had a DLT. One patient on DL1 remains on treatment with stable disease for 42+ cycles. The median number of cycles administered was 3 (range: 1-42+). Severe toxicities reported included grade 3 lymphocytopenia (3), anemia (2), alanine aminotransferase increase (1), aspartate aminotransferase increase (1), blood bilirubin increase (1), hypocalcemia (1), hypokalemia (1) hypophosphatemia (1), febrile neutropenia (1), chronic kidney disease (1), non-viral hepatitis (1), soft tissue infection (1), and fatigue (1); grade 4 lymphocytopenia (1), and grade 5 sepsis (1). End of treatment reasons included: PD (7), toxicity (2), death [soft tissue infection that turned into sepsis considered to be likely related to DEX] (1), and concomitant conditions (2). Stable disease (SD) or better was achieved in 10 of 12 evaluable patients (83%), including one patient who achieved disease control for over 3.5 years. One patient (8%) on DL3 had a complete response (CR) but stopped treatment after 2 cycles due to reversible toxicity and comorbid conditions, based upon physician advice and patient choice. Conclusions: The combination of lenalidomide with Ibrutinib as an all-oral approach in RR MM proved feasible and generally tolerable, with the majority of discontinuation seen in this Phase I study due to disease progression. No COVID related - mortality was seen. SD or better was achieved in 83% of patients, including one CR. Potential future directions include combination approaches with next generation IMids such as pomalidomide, as well as other orally bioavailable novel agents with potent immune activating properties, such as CelMoDs. Support: AFT; Pharmacyclics; Clinicaltrials.gov Identifier: NCT03702725

Abstract BACKGROUND: Multiple Myeloma (MM) is an incurable disease with no known germline high penetrant risk gene. The higher risk of MM among affected relatives suggests a genetic contribution to the etiology. To date, 24 common risk variants with low effect sizes were identified using genome-wide association studies, which account for 17% of heritability. However, a systematic analysis of the known rare alleles in cancer predisposition genes has not been undertaken so far in MM. We collaborated with six other academic centers across the United States to identify and select cases for analysis of germline predisposition of MM. METHODS: We performed whole exome, next-generation sequencing of 2,387 familial or early onset germline MM cases from the myeloma sequencing consortium (MMSEQ). We called 1.5 million variants and performed standard quality control of the data. We also obtained exome data on 1,285 cases from UK Biobank (UKBB) and 344,513 non-cancer controls (total=3,672 cases). We analyzed the ultra-rare, coding variants in 90 clinically relevant or putative candidates for cancer predisposition. We then used the automated variant curator PathoMAN to annotate and assert pathogenicity of each variant. We contrasted our results with assertions of pathogenicity from ClinVar and tested for gene association with MM. RESULTS: Overall, we observed several pathogenic or likely pathogenic variants, both singleton and recurrent founder mutations. In the MMSEQ, 8.7% of MM cases harbored a pathogenic variant in these known/putative cancer predisposition genes. Predominant group of pathogenic variants were observed within CHEK2 (19%), TP53 (8%), and ATM (5%). A case-control analysis revealed strong association with TP53 and weakly with ATM. In the familial/early onset MMSEQ cases, TP53 mutations were enriched 68 times more than in the UKBB controls. Our preliminary results suggest that known genes of cancer susceptibility such as TP53 and ATM may also play a role in myeloma risk. CONCLUSION: In a large study of multi-center MM cases, we identified a significant proportion of individuals who are carriers of known (solid) cancer predisposition genes. This study suggests that these known cancer predisposition genes may be relevant in a subset of MM cases. Citation Format: Michael T. Conry, Nicola Camp, Celine Vachon, Michelle Hildebrandt, Elizabeth E. Brown, Steven M. Lipkin, Judy Garber, Susan L. Slager, Samantha Stokes, Aaron D. Norman, Aalin Izhar, Sita Dandiker, Kylee Maclachlan, Kenneth Offit, Saad Usmani, Vijai Joseph. Pathogenic germline mutations and risk of multiple myeloma. [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 5229.

8037 Background: Both daratumumab in combination with lenalidomide and dexamethasone (DRd) and bortezomib in combination with lenalidomide and dexamethasone (VRd) are endorsed by NCCN guidelines as preferred regimens for the treatment of transplant-ineligible (TIE) patients with newly diagnosed multiple myeloma (NDMM). DRd and VRd have each demonstrated superior efficacy relative to lenalidomide and dexamethasone (Rd) alone in the MAIA and SWOG S0777 trials, respectively, but have not been compared directly in a head-to-head trial. Naive comparisons of efficacy across the 2 trials may be biased because MAIA enrolled only TIE patients (median age 73 years), whereas S0777 enrolled a mixed transplant-not-intended (TNI) population, which included both TIE patients and patients choosing to defer/refuse frontline stem cell transplantation (median age 63 years). Methods: The present study leveraged individual patient-level data (IPD) from both trials to perform an anchored indirect treatment comparison of DRd vs VRd, adjusting for differences in trial eligibility criteria and baseline patient characteristics. Harmonized inclusion criteria (NDMM, age ≥65 years, ECOG performance status ≤2) were applied to both trial populations. Age ≥65 years served as a proxy for TIE status since S0777 enrolled a mixed TNI population. Propensity score (PS) reweighting was used to balance the 2 trial populations on key baseline prognostic factors including age, sex, ISS stage, ECOG performance status, hemoglobin, eGFR, lactate dehydrogenase (LDH) level, and cytogenetic risk. Missing data were addressed with multiple imputation. After alignment of inclusion criteria and PS reweighting, an anchored indirect comparison was performed wherein within-trial progression-free survival (PFS) hazard ratios (HRs) for DRd vs Rd and VRd vs Rd were estimated and used to make indirect inference about PFS for DRd vs VRd. Results: 727 MAIA participants and 198 S0777 participants were eligible for inclusion. After PS reweighting, the trial populations were balanced on the key baseline prognostic factors identified above (standardized difference < 0.1 for each). The adjusted PFS HRs were 0.53 (95% CI: 0.41–0.68; P< 0.0001) for DRd vs Rd in MAIA and 0.88 (0.63–1.23; P= 0.46) for VRd vs Rd in S0777. In the adjusted Rd-anchored indirect comparison, the PFS HR for DRd vs VRd was 0.60 (0.39–0.90; P= 0.02). Conclusions: In this adjusted indirect treatment comparison based on IPD from the MAIA and S0777 trials, PFS was significantly longer for DRd relative to VRd. In the absence of a head-to-head trial comparing DRd and VRd, the present study may help to inform treatment selection in TIE patients with NDMM.

8009 Background: Heavily pretreated patients (pts) with relapsed/refractory multiple myeloma (RRMM) treated with standard of care therapy have median overall survival (OS) of ~12 months (mo). In the single-arm, phase 1b/2 CARTITUDE-1 study (NCT03548207), pts received a single infusion of ciltacabtagene autoleucel (cilta-cel), a CAR-T cell therapy targeting BCMA. At the final protocol-specified analysis (27.7-mo median follow-up [MFU]), overall response rate (ORR) was 98%, with 83% stringent complete response (CR); 27-mo rates of progression-free survival (PFS) and OS were 55% and 70%, respectively. Here, we report study closeout results. Methods: Eligible pts received ≥3 prior lines of therapy (LOT) or were double refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD); and had received prior PI, IMiD, and anti-CD38 antibody therapy. Primary endpoint was ORR and safety; secondary endpoints included PFS, OS, and minimal residual disease (MRD) negativity at 10-5. Results: 97 pts received cilta-cel (median age 61 years [y]; median 6 prior LOT; 42% penta-drug refractory; 88% triple-class refractory; 99% refractory to last LOT). As of October 14, 2022, MFU was 33.4 mo (range, 1.5-45.2). Median (m) duration of response was 33.9 mo (95% CI, 25.5–not estimable [NE]). mPFS was 34.9 mo (95% CI, 25.2–NE), with an estimated 47.5% progression free and alive at 36 mo. mOS was not reached (NR), with an estimated 62.9% survival at 36 mo. Of 49 MRD-evaluable pts, 26 had MRD negativity sustained for ≥12 mo, of which 20 had sustained MRD-negative ≥CR. mPFS was NR in these subgroups (Table). 18 pts were MRD negative with ≥CR at 24 mo post infusion. No new safety signals and no new neurotoxicity events were reported since the 27.7-mo MFU. 6 new cases of second primary malignancy were reported, including 2 cases of basal cell carcinoma and 1 case each of myelodysplastic syndrome, B-cell lymphoma, melanoma, and prostate cancer. 5 additional deaths occurred (progressive disease [PD], n=3; pneumonia and sepsis, n=1 each [both unrelated to cilta-cel]), for a total of 35 (PD, n=17; unrelated to cilta-cel, n=12; related, n=6). Conclusions: Longer mPFS was observed after a single infusion of cilta-cel than any previously reported therapy in heavily pretreated pts with RRMM. Achieving CR and/or sustained MRD negativity was associated with prolonged PFS. Pts continue to be followed for safety and survival in the 15-y CARTINUE long-term study (NCT05201781; MMY4002). Clinical trial information: NCT03548207 . [Table: see text]