A phase Ib trial of isatuximab, bendamustine, and prednisone in relapsed/refractory multiple myeloma.

INTRODUCTION: Patients with triple-class refractory (TCR) multiple myeloma (MM) often need cytoreductive chemotherapy for rapid disease control. Bendamustine is an outpatient-administered, bifunctional alkylator and isatuximab is an anti-CD38 monoclonal antibody with unique cytotoxicity characteristics. We hypothesized that isatuximab-bendamustine-prednisone would be well-tolerated regimen in TCR MM, and conducted single-center, phase Ib, investigator-initiated study. PATIENTS/METHODS: Patients had TCR MM and last daratumumab exposure ≥ 6 weeks. This study was conducted as a 3 + 3 design to establish the maximally tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). Isatuximab 10 mg/kg IV was administered weekly (cycle 1), and every 2 weeks thereafter. Bendamustine was administered on days 1 and 2 at 3 dose levels (DL): 50, 75, and 100 mg/m2. Methylprednisolone was administered as 125 mg on day 1 and prednisone 60 mg days 2-4. Common definitions were used for DLTs, adverse events (CTCAE v 5.0), and disease response. RESULTS: Fifteen patients were treated (3 DL1, 6 DL2, 6 DL3). Median age was 71, 53% had high-risk cytogenetics, and 34% had prior BCMA-targeting therapy. One DLT was observed at DL2 (Grade 3 thrombocytopenia plus bleeding). There were no Grade 5 treatment-related AEs. The MTD was not reached. The overall response rate was 20% (3/15) including one stringent complete response. The median PFS was 2.5 months (95% CI 0.9-4.1 months). CONCLUSION: We demonstrated the safety and tolerability of isatuximab-bendamustine-prednisone. Toxicities were mild and manageable with limited intervention. The study was discontinued due to slow accrual. However, we observed responses even among highly refractory patients. CLINICAL TRIAL REGISTRATION: This study was registered on clinicaltrials.gov as NCT04083898 on 9/6/2019.

Elranatamab in Japanese patients with relapsed/refractory multiple myeloma: results from MagnetisMM-2 and MagnetisMM-3.

BACKGROUND: Despite advances, most patients with multiple myeloma (MM) experience relapse and repeat multiple treatment lines, highlighting an unmet need for patients with relapsed or refractory MM (RRMM). Bispecific antibodies are a new option, but their efficacy and safety in Japanese patients are unknown. METHODS: This was an analysis of Japanese patients receiving elranatamab monotherapy in MagnetisMM-2 (NCT04798586) and MagnetisMM-3 (NCT04649359). Both studies evaluated a priming dose regimen of elranatamab followed by weekly subcutaneous doses, in patients with disease progression while receiving or who were intolerant to ≥3 prior therapies (≥1 proteasome inhibitor, ≥1 immunomodulatory drug and ≥1 anti-CD38 monoclonal antibody). The primary endpoints were dose limiting toxicities (DLTs) in MagnetisMM-2 and confirmed objective response rate (ORR) in MagnetisMM-3. In both, key secondary endpoints included safety, tolerability, duration of response, time to response, progression-free survival and overall survival. RESULTS: In MagnetisMM-2 (N = 4) and MagnetisMM-3 (n = 12), median ages were 68.5 and 66.5 years, respectively. No DLTs were observed in MagnetisMM-2. ORRs were 50.0% (95% CI, 6.8-93.2) and 58.3% (95% CI, 27.7-84.8) in MagnetisMM-2 and MagnetisMM-3, respectively. All patients experienced treatment-emergent adverse events in MagnetisMM-2 (grade 3/4: 75.0%) and MagnetisMM-3 (grade 3/4: 100%); cytokine release syndrome occurred in 100% (grade 3/4: 25.0%) and 58.3% (no grade 3/4) of patients, respectively. Neither study reported immune effector cell-associated neurotoxicity syndrome. CONCLUSIONS: No new safety signals were observed, and ORRs were similar to that of the overall MagnetisMM-3 trial population, supporting further studies of elranatamab in Japanese patients with RRMM. ClinicalTrials.gov identifier: NCT04798586 (MagnetisMM-2), NCT04649359 (MagnetisMM-3).

An open-label phase 2 study treating patients with first or second relapse of multiple myeloma with carfilzomib, pomalidomide, and dexamethasone (KPd): SELECT study.

Once-weekly carfilzomib at 56 mg/m2 plus immunomodulatory drugs and dexamethasone has shown efficacy and tolerability treating early relapsed/refractory multiple myeloma (RRMM). The phase 2 SELECT study (NCT04191616) evaluated efficacy/safety of weekly carfilzomib, pomalidomide, and dexamethasone (KPd) in early RRMM patients refractory to lenalidomide. All 52 treated patients were refractory to prior treatment, and 19 (37%) were triple-class refractory. Overall response rate (ORR; primary endpoint) was 58% (35% ≥ very good partial response, 6% ≥ complete response); median response duration was 20.3 months. Minimal residual disease negativity (10-5) was achieved in 10% of patients. Median progression-free survival was 11.1 months; median overall survival was 18.8 months. Adverse events (AEs) were consistent with the known safety profile including grade ≥3 treatment-emergent AEs reported in 67% of patients. Although the primary endpoint of ORR was not met, KPd showed meaningful clinical benefits in lenalidomide-refractory RRMM patients, including those who were daratumumab-refractory and/or triple-class refractory.

Assessment of algorithms for identifying patients with triple-class refractory multiple myeloma using real-world data.

Objective: Patients with triple-class refractory (TCR) multiple myeloma (MM) have limited treatment options and poor prognoses. This high unmet need has prompted the development of new therapies allowing for improved outcomes for these patients. Recently, new targeted therapies for the treatment of patients with relapsed or refractory MM have been approved based on single-arm clinical trial results. Real-world (RW) data enable a better understanding of the effectiveness of new therapies in clinical practice and provide external controls for single-arm studies. However, using RW data to identify patients with TCR MM is challenging and subject to limitations. Methods: In this retrospective cohort study of an analysis of the COTA electronic health record (EHR) database, we used four algorithms to define refractory status and created four groups of patients with TCR MM initiating post-TCR therapy. Each algorithm relied on slightly different criteria to identify TCR patients, but all were based on the International Myeloma Working Group (IMWG)-derived and/or healthcare provider (HCP)-reported progressions within the database. Results: A total of 3815 patients with newly diagnosed MM met the eligibility criteria for this study. The choice of the algorithm did not impact the characteristics of identified patients with TCR MM (Algorithm 1 [n = 404], Algorithm 2 [n = 123], Algorithm 3 [n = 404], and Algorithm 4 [n = 375]), including their demographic and disease characteristics, MM treatment history, or treatment patterns received after becoming TCR. However, identifying TCR MM using a combination of IMWG-derived and HCP-reported progressions allowed up to a 70% increase in the size of the identified group of patients compared with using only IMWG-derived progressions. Conclusion: In RW settings, progressions from both IMWG-derived data and physician reports may be used to identify patients with TCR MM.

Elranatamab efficacy in MagnetisMM-3 compared with real-world control arms in triple-class refractory multiple myeloma.

Elranatamab efficacy in the single-arm, registrational MagnetisMM-3 trial (NCT04649359) was compared with that of physician's choice of treatment (PCT) for triple-class refractory multiple myeloma. MagnestisMM-3 eligibility criteria were applied to two USA-based oncology electronic health record databases, COTA and Flatiron Health (FH), to identify cohorts for this study (NCT05932290). Applied statistical techniques accounted for cohort imbalances. MagnetisMM-3 (BCMA-naive; n = 123) outcomes were compared with those from COTA (n = 239) and FH (n = 152). Elranatamab was associated with a significantly higher objective response rate (risk ratios, 1.88-2.25), significantly longer progression-free survival (hazard ratios [HRs], 0.37-0.57), and, across most analyses, significantly longer overall survival (HRs, 0.46-0.66) versus PCT. BCMA-naive patients who were treated with elranatamab exhibited significantly better outcomes than patients treated in real-world clinical practice.

Elranatamab is a new medicine for the treatment of people with multiple myeloma. In the ongoing clinical trial MagnetisMM-3, most people had fewer myeloma cells when treated with elranatamab. However, MagnetisMM-3 only looks at the effects of elranatamab without comparing it to other myeloma treatments. Therefore, a new study was designed to compare the effectiveness of elranatamab in the MagnetisMM-3 study with other treatments used in real-world clinical practice (not in a clinical trial). Data from people in MagnetisMM-3 was compared with data from two US databases (COTA and Flatiron Health) containing health records of patients treated for multiple myeloma in real-life clinical practice. The same criteria used to select patients for the MagnetisMM-3 trial (123 people) were used to identify people with similar characteristics in COTA (239 people) and Flatiron Health (152 people). More people treated with elranatamab had fewer myeloma cells in their bodies after treatment than people who received their doctor's choice of treatment in clinical practice. In fact, six out of ten people treated with elranatamab had fewer myeloma cells versus about three in ten people from each real-world database. People treated with elranatamab versus physician's choice of treatment lived longer without their disease getting worse and lived longer overall. In conclusion, this study found that more people treated with elranatamab responded to treatment and lived longer than similar people from the COTA and Flatiron Health databases who were given treatments available in a real-world clinical setting.Clinical Trial Registration: NCT05932290 (ClinicalTrials.gov).

Real-World Clinical Outcomes in Patients With Multiple Myeloma Administered With Elotuzumab-Based Treatment.

Objective Elotuzumab is used to treat relapsed and/or refractory multiple myeloma (MM). However, the optimal patient selection and sequencing in MM therapy are less clear. Therefore, this retrospective cohort study assessed the clinical outcomes of patients with MM who underwent elotuzumab-based therapy. Methods We reviewed the medical records of 85 patients with relapsed/refractory MM who received elotuzumab for the first time. Participants were divided into progressive disease (PD group) and those without PD (non-PD group) at elotuzumab treatment initiation, and each group was analyzed separately. Survival rates were calculated using Kaplan-Meier curves and compared using log-rank tests. Results The median follow-up period was 33.6 (range: 0.5-72.0) months. The median progression-free survival (PFS) and overall survival (OS) of PD and non-PD groups at elotuzumab therapy initiation were 5.3 months and not reached (NR), respectively (P < 0.0001), and 26.8 months and NR, respectively. Patients with triple-class refractory disease in both groups had worse PFS and OS. Twenty-one patients in the non-PD group received elotuzumab as post-hematopoietic stem cell transplantation, whose PFS and OS were NR (95% CI, 21.4 months-NR) and NR (95% CI, NR-NR), respectively. Conclusions Elotuzumab exhibited limited therapeutic efficacy in patients with triple-class refractory MM but better treatment outcomes in situations with adequate disease control and post-transplant treatment.

Real-world clinical outcomes in patients with multiple myeloma treated with isatuximab after daratumumab treatment.

Isatuximab and daratumumab are anti-CD38 monoclonal antibodies used to treat refractory multiple myeloma. Isatuximab is often used after unsuccessful daratumumab treatment; however, the clinical benefits of receiving isatuximab after daratumumab treatment have not been fully evaluated. Therefore, this retrospective cohort study assessed the clinical outcomes of 39 patients with multiple myeloma who were administered isatuximab after daratumumab. The median follow-up period was 8.7 months (range 0.1-25.0 months). The overall response rate was 46.2% (18 patients). The 1-year overall survival was 53.9%, with a median progression-free survival of 5.6 months. The median progression-free survival in patients with high and normal lactate dehydrogenase levels was 4.5 and 9.6 months, respectively (P = 0.004). The median progression-free survival in patients with and without triple-class refractory disease was 5.1 months and not reached, respectively (P = 0.001). The median overall survival in patients with high and normal lactate dehydrogenase levels was not reached and 9.3 months, respectively (P = 0.001). The median overall survival in patients with and without triple-class refractory disease was 9.9 months and not reached, respectively (P = 0.038). Our findings provide insight into the optimal use and timing of anti-CD38 antibody therapy.

Clinical efficacy of retreatment of daratumumab-based therapy (D2) in daratumumab-refractory multiple myeloma.

Daratumumab demonstrates activity as a single agent and in combination with either immunomodulatory agents (IMiDs) or proteasome inhibitors (PIs) in relapsed refractory multiple myeloma (RRMM). However, little is known about the benefit of daratumumab retreatment in daratumumab-refractory MM. This study aimed to analyze the clinical efficacy of daratumumab-based retreatment (D2) in patients who are daratumumab refractory MM. Retrospectively, we identified 43 RRMM patients from a single-center database review. The median age was 65 years, 42% patients had high-risk cytogenetics, and 23% had an extramedullary disease, while the median time between D2 and prior daratumumab was 1 (0.25-39) month. All D2 patients received combination therapy with either pomalidomide, carfilzomib, bortezomib, or lenalidomide. The response rate, median progression-free, and overall survival were 49%, 7.97 and 32.6 months, respectively. Our study raises the possibility of re-utilizing daratumumab in combination with different classes of anti-myeloma drugs to generate responses in RRMM patients who are daratumumab-refractory.

Carfilzomib, cyclophosphamide, and dexamethasone (KCd) for the treatment of triple-class relapsed/refractory multiple myeloma (RRMM).

BACKGROUND: Multiple myeloma (MM) is an incurable hematologic malignancy, and outcomes remain poor for patients with triple-class relapsed/refractory MM (RRMM). Descriptive analyses were performed on available data for patient characteristics, disease course, and outcomes of the KCd on triple-class RRMM patients at our institution. PATIENTS AND METHODS: Twenty-three patients with triple-class RRMM treated with KCd between June 2017 and October 2020 were included in our analysis. The regimen KCd consisted of 28 days cycles of carfilzomib 20/36 mg/m2 IV on days 1, 2, 8, 9, 15, and 16, cyclophosphamide 300 mg/m2 IV weekly, and dexamethasone (20-40) mg orally weekly. RESULTS: Patients received a median of 6 (3-10) prior regimens. The median number of cycles administered was 4 (1-11) cycles. Overall response rate was 52%, 6 patients (26%) achieved very good partial response (VGPR), 6 patients (26%) achieved partial response (PR), and 5 patients (22%) achieved stable disease (SD). Progression-free survival (PFS) and Overall-survival (OS) were 4 and 11.9 months, respectively. There was no reported treatment-related mortality. The most common grade ≥3 adverse events were neutropenia (26%), thrombocytopenia (56.5%), and anemia (56.5%). CONCLUSIONS: KCd showed clinically meaningful efficacy and manageable safety profile in patients with triple-class RRMM in real-world.

Overall survival with oral selinexor plus low-dose dexamethasone versus real-world therapy in triple-class-refractory multiple myeloma.

Triple-class-refractory multiple myeloma (MM) describes MM refractory to proteasome inhibitors, immunomodulatory agents, and anti-CD38 monoclonal antibodies. In the Phase IIb STORM study (NCT02336815), oral selinexor plus low-dose dexamethasone (Sel-dex) demonstrated a 26.2% overall response rate in triple-class-refractory MM. Here, we compare overall survival (OS) of 122 patients with triple-class-refractory MM who received Sel-dex in STORM Part 2 with that of 64 similar patients treated with other available therapies in a Flatiron Health Analytic Database (FHAD) cohort. OS from the date that the patients' MM became triple-class-refractory was longer in STORM versus FHAD, with an unadjusted hazard ratio (HR) of 0.43 (P =  .0002; adjusted HR 0.35 [P  =  .011]). In a subset analysis of highly resistant patients receiving further therapies after their MM first became at least triple-class-refractory (i.e., who received Sel-dex in STORM, n = 64, and non-Sel-dex in FHAD, n = 36), the OS was significantly longer in STORM with an unadjusted HR of 0.52 (P = .0331; adjusted HR 0.33 [P = .041]). Within the limits of this analysis, the OS of patients with at least triple-class-refractory MM was significantly better with Sel-dex versus available therapies, suggesting that Sel-dex may be associated with a meaningful OS benefit in these patients.

Treatment Options for Triple-class Refractory Multiple Myeloma.

The advent of new, more effective, and less toxic therapies has revolutionized the management of multiple myeloma in the past decade. Despite the availability of new treatments, most patients with multiple myeloma will become refractory to the therapies that currently comprise the hematologic standard of care for the malignancy, including proteasome inhibitors, immunomodulatory agents, and monoclonal antibodies. Moreover, in recent years, a new subset of patients with multiple myeloma refractory to all 3 of these agents has emerged. This population, for whom a clear treatment paradigm has remained undefined, has been characterized by poor survival outcomes. The current approaches to the treatment of triple-class refractory disease are limited and include conventional chemotherapy, salvage autologous stem cell transplantation, and recycling previous regimens, each of which have generally had short-lived efficacy. It is anticipated that additional agents will be available for triple-refractory disease in the near future, including selinexor, chimeric antigen receptor T-cell therapy, and next-generation monoclonal antibodies. The development and further refinement of novel treatments for this subset of patients should be considered a key clinical and research priority.