Holstein, Sarah A.

7528 Background: Lenalidomide (Len) maintenance after ASCT has been a standard of care for patients (pts) with MM. Historically, ~30% of pts discontinue Len within 1 year (yr) due to toxicity and there is a need for more effective and better tolerated maintenance strategies. Iber is a potent, oral cereblon E3 ligase modulator under evaluation in the relapsed/refractory and newly diagnosed settings. We report the results of the primary analysis of a Phase II trial of Iber maintenance following upfront ASCT. Methods: Pts ≥ 19 yrs of age with MM, within 1-yr of initiation of induction therapy and in a ≥ partial response (PR) at day 80-110 post-ASCT, were accrued. Iber was administered 1.0 mg orally days 1-21 of a 28-day cycle, continued until progressive disease (PD) or toxicity. Up to 2 dose reductions (0.75 mg/day then 0.6 mg/day) were allowed. Growth factor support was not permitted. Minimal residual disease (MRD) assessment by flow cytometry (10 -5 ) was performed at registration, post-cycle 12 and post-cycle 24. An optimal Simon two-stage design with type I and II errors of 0.1 was chosen to test whether the proportion of pts who are progression-free and on treatment at 1 yr is <60% against the alternative of ≥ 80%. If ≥ 27 out of 38 pts were progression-free (by 2016 IMWG criteria) and on treatment at 1 yr, Iber would be considered to have promising activity. Results: 38 pts (55% males, median age 61 yrs (range: 41-77)) received Iber. R-ISS at diagnosis was stage I (34%), II (39%), III (8%) and unknown (18%), with 34% having high-risk disease per 2025 IMS/IMWG criteria. All pts received triplet or quadruplet induction therapy, with 97% receiving Len and 84% receiving daratumumab. At day 80-110 post-ASCT, all pts had ≥ very good PR, with 22 (58%) ≥ complete response (CR) and 33 (87%) MRD-negative (neg). The median number of administered treatment cycles is 18 (range: 1-45), with 18 (47%) pts having ≥ 1 dose reduction, most commonly due to neutropenia (n=12). The most common grade (gr) 3/4 adverse event was neutropenia (gr 3 (n=19), gr 4 (n=5)). Within yr 1, 29% (11/38) discontinued Iber due to neutropenia (n=5), rash (n=1), infection (n=1), pt choice (n=1), or PD (n=3). After 1 yr, 6 pts discontinued due to neutropenia (n=4) and PD (n=2). While on Iber, 19 pts had deepening of response to stringent CR and 3 pts converted from MRD-positive to MRD-neg. The post-cycle 12 and 24 MRD-neg rates are 85% (23/27) and 100% (14/14), respectively. Conclusions: Iber demonstrated promising activity with dose reductions/discontinuations mainly due to neutropenia. Strategies including lower starting dose, growth factor support and more flexible management of neutropenia may enable more pts to remain on treatment. Longer follow-up will permit evaluation of sustained MRD-negativity and PFS, but overall, these results provide rationale for further exploration of Iber-based post-ASCT maintenance strategies. Clinical trial information: NCT05177536 .

Multiple myeloma (MM) is an incurable cancer of plasma cells with nearly 70% of all new diagnoses occurring in adults aged ≥ 65 years. For older adults, medical comorbidities and functional deficits become increasingly more prevalent with increased age and can impact disease outcomes and survival. There are unmet medical needs in this vulnerable patient population who are not eligible for autologous stem cell transplantation to optimize the frontline therapy for better survival and less toxicity. This randomized phase 3 clinical trial is designed to focus on real world patient population to identify an optimal frontline three drug regimen in frail or a subset of intermediate fit newly diagnosed MM patients. Diagnostic criteria and response criteria will be based on IMWG guidelines. Participants must have a calculated myeloma frailty index (Myeloma Frailty Score Calculator (http://www.myelomafrailtyscorecalculator.net/) categorized as frail or intermediate fit (regardless of age) within 28 days prior to registration (NCT05561387). The two most commonly used induction/maintenance regimens in this patient population will be compared, including RVd-Lite (lenalidomide (R), bortezomib (V), and dexamethasone (dex) followed by R maintenance) and DRd (Daratumumab, lenalidomide, and dex followed by R or R-daratumumab maintenance). The study will include three cohorts: (1) RVd-Lite induction followed by Rev maintenance (2) DRd induction followed by Rev maintenance (3) DRd induction followed by D-R maintenance. Induction phases will be 9 cycles in total of 28 days each, followed by maintenance for cycle 10 and beyond in all cohorts until disease progression: V 1.3 mg/m2 on days 1, 8, 15, 22, R 15 mg days 1-21, dex 20 mg days 1, 8, 15, 22 for induction phase and R 10 mg days 1-21 for maintenance phase in cohort 1 (VRd-Lite); SubQ Dara 1800 mg (on days 1, 8, 15, 22 for C1-2, on days 1, 15 for C3-6, on day 1 for C7-9), R 15 mg day 1-21, dex 20 mg days 1, 8, 15, 22 for induction phase and R 10 mg days 1-21 for maintenance in cohort 2 (DRd-R); SubQ Dara 1800 mg (on days 1, 8, 15, 22 for C1-2, on days 1, 15 for C3-6, on day 1 for C7-9), R 15 mg day 1-21, dex 20 mg days 1, 8, 15, 22 for induction phase and Dara 1800mg on day 1 and R 10mg days 1-21 for maintenance in cohort 3 (DRd-DR). The dual primary objectives are (A) to compare progression free survival (PFS) between cohorts 1 (VRd-Lite) and 2 (DRd-R); (B) to compare overall survival (OS) between cohorts 1 (VRd-Lite) and 3 (DRd-DR). Quality of life objectives are to compare patient reported global health status between treatment arms at the end of induction therapy using the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire. A total of 459 eligible patients will be enrolled in this randomized three cohort trial. It is hypothesized that Cohort 1 will have a median PFS of 2.667 years and a median OS of 5 years. With 153 eligible participants per cohort accrued over 5 years, and an additional follow-up period of 3 years, this trial has 80% power to detect an increase in the median PFS in Cohort 2 from 2.667 years to 4 years, and 83.4% power to detect an increase in the median OS in Cohort 3 from 5 years to 8.5 years, each with a one-sided type I error rate of 2%. This trial will be conducted among the NCI cooperative groups SWOG, ALLIANCE, and ECOG/ACRIN and incorporate substantial involvement from NCORP and VA member sites. This study is anticipated to provide practice changing data for this transplant-ineligible real world population to achieve deeper and longer remissions with less side effects and better quality of life.

e20021 Background: CAR T cell therapies are FDA approved for patients with triple refractory multiple myeloma (MM) and >4 lines of therapy. The median survival of this is group is less than 12 months so salvage therapies need to be implemented quickly. Real-world access to CAR T remains challenging due to supply chain limitations impacting manufacturing. The goal of this study was to evaluate how centers are handling the challenges of CAR T slot allocation. Methods: MM CAR T physician leaders at each CAR T treatment center certified for idecabtagene vicleucel across the US were surveyed. Results: We received responses from 15/20 centers. Summary of CAR T volumes and outcomes of patient on waitlists are shown in the table. The median time on the waiting list was 6 months with only 25% of patients receiving CAR T eventually. For patient selection, all centers reported using a committee of experienced CART physicians to ensure consistency. Selection committee included: primary MD (n=9), CAR T MD (n=12), social workers (n=3), CAR T RN (n=10), APP (n=2), pharmacists (n=2) and ethicists (n=1). To ensure transparency, centers have clear selection criteria (n=10), priority score (n=8) and selection timeline (n=11) . To ensure accountability, centers document priority scores (n=5) and have pre-specified criteria (n=9) for selection. Centers also reported using ethical principles for selection: a) equal treatment: time spent on waiting list (n=8); b) priority to the worst-off: limited therapeutic options (n=10), MM burden (n=7), ineligible for trials (n=2); c) maximize benefit: most likely to complete apheresis (n=8) or infusion (n=8) or achieve response (n=6) and d) social value: younger pts (n=2). Maximizing benefit was considered the most important criterion by 7 centers. Conclusions: More stringent GMP manufacturing requirements with FDA approved CAR T and real-world practice with broader patient demographics can present challenges to implementation of CAR T in standard of practice. Our study is the first attempt to evaluate and highlight existing issues with MM CAR T access and the variability and challenges in patient selection. Learning from other models of resource allocation (ex: UNOS) and sharing experience across centers can help providers optimize slot allocation to improve accrual. Increasing supplies of key reagents and novel manufacturing methods(eg: non-viral vectors and allogeneic CAR) could help overcome these limitations. [Table: see text]

Autologous stem cell transplantation (ASCT) has been a backbone of therapy for newly diagnosed patients with multiple myeloma eligible for high-dose therapy for decades. Survival outcomes have continued to improve over time, in part because of the incorporation of highly effective induction regimens prior to ASCT as well as post-ASCT maintenance therapy. Randomized phase III clinical trials have helped establish lenalidomide maintenance as a standard of care. However, as nearly all patients will eventually experience disease relapse, there continues to be significant interest in developing novel maintenance strategies to improve upon lenalidomide maintenance. In this review, we summarize the available evidence for the use of immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies as post-ASCT maintenance therapies as well as discuss future directions and unanswered questions in the field.

Abstract Background: The phase 3 double-blind, CALGB/Alliance 100104 study assessed the efficacy and safety of lenalidomide (LEN) or placebo maintenance therapy until relapse in post-autologous stem cell transplantation (ASCT) patients with newly-diagnosed multiple myeloma (NDMM). Interim analyses demonstrated superiority for LEN versus placebo for time to progression (TTP), thus meeting the primary TTP endpoint of the trial. The study was unblinded in December 2009 and, based on the TTP and overall survival (OS) benefit observed with LEN, patients in the placebo arm (who had not yet progressed) at the time of unblinding were given the option of crossing over to receive LEN. Data have been reported for a follow-up of 91 months based on the planned intention to treat (ITT) analysis, yielding a TTP hazard ratio (HR) 0.57 and an OS difference of HR 0.61 (Holstein SA, et al. Lancet Haematol. 2017;4:e431-42). Crossover to active treatment enabled patients to benefit from LEN maintenance and collection of additional efficacy and safety data; however, crossover can confound the estimates of OS for longer follow-up. We report the results of an analysis adjusted for crossover, thus aiming to provide a more accurate estimate of the survival benefit achieved with LEN maintenance therapy. Methods: Results are reported for an analysis based on an updated data cutoff, post-October 2016. The rank-preserving structural failure time model (RPSFTM) was considered the most appropriate method to adjust for crossover (Robins JM, Tsiatis AA. Commun Stat Theory Methods. 1991;20:2609-31). This method requires that the assumption that the treatment effect is the same for patients who receive LEN at randomization as those who receive LEN as crossover treatment is not violated; a landmark analysis was performed to explore this. The iterative parameter estimation (IPE; Branson M, Whitehead J. Stat Med. 2002;21:2449-63) algorithm was used as validation. Both the RPSFTM and IPE analyses assume a residual LEN effect after discontinuation (base case). Results: A total of 76 NDMM patients who had not progressed, as determined by central adjudication, crossed over from placebo to LEN and were included in the analysis. The landmark analysis of OS from the date of unblinding indicated that the treatment effect for the crossover versus the non-crossover placebo group was HR 0.57 (95% confidence interval [CI] 0.29-1.15) (Figure). This also provided a measure of the benefit of LEN maintenance in patients who started maintenance therapy after the trial-specified 90-100 day window post-ASCT (median 11.5 months post-randomization; range 3.2-51.0 months). Adjustment for crossover using the RPSFTM or IPE resulted in an increase in the relative treatment effect of LEN maintenance (vs placebo) on OS from 30.8 months for the ITT analysis (HR 0.61; 95% CI 0.47-0.81) to 40.1 months (HR 0.52; 95% CI 0.36-0.73) for the RPSFTM analysis and 38.8 months (HR 0.52; 95% CI 0.37-0.74) for the IPE analysis (Table). Results were consistent across the two methods. Discussion: This analysis was performed on an updated version of the data set reported in the Holstein article. Once we adjusted for crossover, depending on the methodology used, there was an additional gain of ~40 months of OS. Previously, a pre-planned, pooled meta-analysis of 3 studies that included CALGB/Alliance (McCarthy PL, et al J Clin Oncol. 2017;35:3279-89) indicated that the OS gain was 2.5 years; however, our analysis from the CALGB study alone shows that LEN maintenance may provide a survival benefit of > 3 years. In diseases where prolonged follow-up is required to demonstrate survival benefits, allowing patients to crossover to active treatment may be important to facilitate this. However, the results should be analyzed appropriately to enable assessment of the value of the therapy. As this analysis indicates, the value of active treatment may be underestimated if adjustment for crossover is not performed. In conclusion, the data reported here provide further insight into the survival benefits of LEN maintenance therapy post-ASCT and support guideline recommendations to offer LEN maintenance therapy to all patients post-ASCT. Support: U10CA180821, U10CA180882, U10CA180820; ClinicalTrials.gov Identifier: NCT00114101. Disclosures McCarthy: Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Richardson:Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Cooper:Celgene: Consultancy; BresMed Health Solutions Ltd: Employment. Saunders:Celgene: Consultancy; BresMed Health Solutions Ltd: Employment. Dhanasiri:Celgene: Employment, Equity Ownership. Anderson:Bristol Myers Squibb: Consultancy; Millennium Takeda: Consultancy; C4 Therapeutics: Equity Ownership, Other: Scientific founder; Celgene: Consultancy; OncoPep: Equity Ownership, Other: Scientific founder; Gilead: Membership on an entity's Board of Directors or advisory committees. Stadtmauer:Celgene: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Takeda: Consultancy. Holstein:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Lenalidomide is a derivative of thalidomide and belongs to the class of drugs known as the immunomodulatory drugs (IMiDs). The IMiDs have played a large role in improving the survival outcomes of patients with multiple myeloma. In particular, lenalidomide is currently standard of care in the newly diagnosed setting, in the maintenance setting post-autologous stem cell transplant, as well as in the relapsed/refractory setting. While the combination of lenalidomide and various proteasome inhibitors has proven particularly effective, there are emerging data demonstrating the effectiveness of lenalidomide in combination with other important classes of drugs including the monoclonal antibodies. Recent studies have provided insight into the molecular target of lenalidomide and the other IMiDs, although there is still much to be learned regarding the mechanisms by which lenalidomide affects the myeloma cell and the immune system. Here we review the molecular mechanisms of action, side effects, and the results of the clinical trials which have led to the widespread incorporation of lenalidomide into the myeloma therapeutic armamentarium.