In eligible patients with newly diagnosed multiple myeloma (NDMM), frontline autologous stem cell transplant (ASCT) is standard of care.1 However, the use of consolidation after ASCT remains controversial, with landmark trials yielding conflicting results.2–4 There is interest in consolidation regimens that are efficacious yet less toxic and more convenient. A potential candidate is the all-oral triplet of ixazomib, lenalidomide and dexamethasone (IRd), which reduces required healthcare visits relative to other proteasome inhibitor (PI)-based regimens.5 A second unresolved aspect of post-ASCT therapy is the optimal maintenance strategy. Lenalidomide maintenance is standard of care, but is associated with significant toxicities, leading to a discontinuation rate of approximately 50% at 2 years.6 Two years of post-ASCT maintenance ixazomib was demonstrated to improve PFS relative to placebo, with a toxicity profile comparable to the control arm.7 However, randomized data comparing lenalidomide and ixazomib is lacking.

Introduction: The present study evaluated the pharmacokinetics and safety of elotuzumab, a humanized IgG1 monoclonal antibody against signaling lymphocyte activation molecule-F7, combined with lenalidomide and dexamethasone, in patients with multiple myeloma (MM) and renal impairment. Patients and Methods: Patients with MM and normal renal function (NRF) (creatinine clearance [CrCl] ≥ 90 mL/min), severe renal impairment (SRI) (CrCl < 30 mL/min, not requiring dialysis), or end-stage renal disease (ESRD) (requiring dialysis) were enrolled in this open-label, phase Ib study. Elotuzumab (10 mg/kg), lenalidomide (5-25 mg), and dexamethasone (40 mg) were administered in 28-day cycles until disease progression or unacceptable toxicity developed. The primary endpoint was single-dose elotuzumab pharmacokinetics. Results: A total of 26 patients (median age, 63 years) were treated (NRF, n = 8; SRI, n = 9; ESRD, n = 9). The median baseline CrCl was 105 mL/min (range, 84-146 mL/min) for those with NRF and 26 mL/min (range, 15-33 mL/min) for those with SRI. Twenty-three patients (89%) had received previous therapy (median, 2 regimens; range, 1-7). Treatment was discontinued in 6 patients with NRF, 4 with SRI, and 5 with ESRD, primarily because of disease progression. The mean elotuzumab serum concentrations were comparable across groups (n = 23). No statistically significant differences were observed in the maximum observed serum concentration, area under the concentration-time curve from time 0 to the last quantifiable serum concentration, or area under the concentration-time curve from time 0 to infinity when the SRI and ESRD groups were compared with the NRF group (P > .05). All patients had ≥ 1 adverse event (AE). Of the 8 patients with NRF, 9 with SRI, and 9 with ESRD, 7, 8, and 7 experienced grade 3 to 4 AEs. The overall response rates were 75% in the NRF, 67% in the SRI, and 56% in the ESRD groups. Conclusion: The results of the present study support the use of elotuzumab for the treatment of patients with MM and renal dysfunction without dose adjustment.

High cytogenetic risk abnormalities confer poor outcomes in multiple myeloma patients. In POLLUX, daratumumab/lenalidomide/dexamethasone (D-Rd) demonstrated significant clinical benefit versus lenalidomide/dexamethasone (Rd) in relapsed/refractory multiple myeloma (RRMM) patients. We report an updated subgroup analysis of POLLUX based on cytogenetic risk. The cytogenetic risk was determined using fluorescence in situ hybridization/karyotyping; patients with high cytogenetic risk had t(4;14), t(14;16), or del17p abnormalities. Minimal residual disease (MRD; 10–5) was assessed via the clonoSEQ® assay V2.0. 569 patients were randomized (D-Rd, n = 286; Rd, n = 283); 35 (12%) patients per group had high cytogenetic risk. After a median follow-up of 44.3 months, D-Rd prolonged progression-free survival (PFS) versus Rd in standard cytogenetic risk (median: not estimable vs 18.6 months; hazard ratio [HR], 0.43; P < 0.0001) and high cytogenetic risk (median: 26.8 vs 8.3 months; HR, 0.34; P = 0.0035) patients. Responses with D-Rd were deep, including higher MRD negativity and sustained MRD-negativity rates versus Rd, regardless of cytogenetic risk. PFS on subsequent line of therapy was improved with D-Rd versus Rd in both cytogenetic risk subgroups. The safety profile of D-Rd by cytogenetic risk was consistent with the overall population. These findings demonstrate the improved efficacy of daratumumab plus standard of care versus standard of care in RRMM, regardless of cytogenetic risk.

In POLLUX, daratumumab (D) plus lenalidomide/dexamethasone (Rd) reduced the risk of disease progression or death by 63% and increased the overall response rate (ORR) versus Rd in relapsed/refractory multiple myeloma (RRMM). Updated efficacy and safety after >3 years of follow-up are presented. Patients (N = 569) with ≥1 prior line received Rd (lenalidomide, 25 mg, on Days 1–21 of each 28-day cycle; dexamethasone, 40 mg, weekly) ± daratumumab at the approved dosing schedule. Minimal residual disease (MRD) was assessed by next-generation sequencing. After 44.3 months median follow-up, D-Rd prolonged progression-free survival (PFS) in the intent-to-treat population (median 44.5 vs 17.5 months; HR, 0.44; 95% CI, 0.35–0.55; P < 0.0001) and in patient subgroups. D-Rd demonstrated higher ORR (92.9 vs 76.4%; P < 0.0001) and deeper responses, including complete response or better (56.6 vs 23.2%; P < 0.0001) and MRD negativity (10–5; 30.4 vs 5.3%; P < 0.0001). Median time to next therapy was prolonged with D-Rd (50.6 vs 23.1 months; HR, 0.39; 95% CI, 0.31–0.50; P < 0.0001). Median PFS on subsequent line of therapy (PFS2) was not reached with D-Rd versus 31.7 months with Rd (HR, 0.53; 95% CI, 0.42–0.68; P < 0.0001). No new safety concerns were reported. These data support using D-Rd in patients with RRMM after first relapse.

A Phase 2 dose-finding study evaluated isatuximab, an anti-CD38 monoclonal antibody, in relapsed/refractory multiple myeloma (RRMM; NCT01084252). Patients with ≥3 prior lines or refractory to both immunomodulatory drugs and proteasome inhibitors (dual refractory) were randomized to isatuximab 3 mg/kg every 2 weeks (Q2W), 10 mg/kg Q2W(2 cycles)/Q4W, or 10 mg/kg Q2W. A fourth arm evaluated 20 mg/kg QW(1 cycle)/Q2W. Patients (N = 97) had a median (range) age of 62 years (38–85), 5 (2–14) prior therapy lines, and 85% were double refractory. The overall response rate (ORR) was 4.3, 20.0, 29.2, and 24.0% with isatuximab 3 mg/kg Q2W, 10 mg/kg Q2W/Q4W, 10 mg/kg Q2W, and 20 mg/kg QW/Q2W, respectively. At doses ≥10 mg/kg, median progression-free survival and overall survival were 4.6 and 18.7 months, respectively, and the ORR was 40.9% (9/22) in patients with high-risk cytogenetics. CD38 receptor density was similar in responders and non-responders. The most common non-hematologic adverse events (typically grade ≤2) were nausea (34.0%), fatigue (32.0%), and upper respiratory tract infections (28.9%). Infusion reactions (typically with first infusion and grade ≤2) occurred in 51.5% of patients. In conclusion, isatuximab is active and generally well tolerated in heavily pretreated RRMM, with greatest efficacy at doses ≥10 mg/kg.

Even though multiple myeloma remains incurable, mean overall survival has improved dramatically as newer game-changing therapies enter the scene. At the same time, treatment decisions and the management of toxicities related to newer drug regimens are becoming more complex.

Protein homeostasis is critical for maintaining eukaryotic cell function as well as responses to intrinsic and extrinsic stress. The proteasome is a major portion of the proteolytic machinery in mammalian cells and plays an important role in protein homeostasis. Multiple myeloma (MM) is a plasma cell malignancy with high production of immunoglobulins and is especially sensitive to treatments that impact protein catabolism. Therapeutic agents such as proteasome inhibitors have demonstrated significant benefit for myeloma patients in all treatment phases. Here, we demonstrate that the 11S proteasome activator PA28α is upregulated in MM cells and is key for myeloma cell growth and proliferation. PA28α also regulates MM cell sensitivity to proteasome inhibitors. Downregulation of PA28α inhibits both proteasomal load and activity, resulting in a change in protein homeostasis less dependent on the proteasome and leads to cell resistance to proteasome inhibitors. Thus, our findings suggest an important role of PA28α in MM biology, and also provides a new approach for targeting the ubiquitin-proteasome system and ultimately sensitivity to proteasome inhibitors.

Bortezomib-containing combinations are active in non-Hodgkin lymphoma (NHL) although peripheral neuropathy can limit their dose intensity. Based on our phase I findings, we conducted a phase II trial of bortezomib in combination with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) with a modified dose of vincristine. Patients with untreated indolent NHL received bortezomib (1·6 mg/m2) on days 1 and 8 of a 21-day cycle for up to 8 cycles and R-CHOP with a 1·5 mg cap of vincristine. Patients achieving a complete response (CR) received maintenance rituximab, and remaining patients received maintenance rituximab and bortezomib. The primary endpoint was CR rate; secondary survival analyses were evaluated using the Kaplan-Meier method. Among 29 eligible patients, NHL morphologies included follicular (n = 20), marginal zone (n = 5) and small lymphocytic lymphoma (n = 4). Nineteen patients had CR (66%) and 10 had partial response (34%), yielding a 100% overall response rate. With a median follow-up of 48·7 months, the 4-year progression-free and overall survivals were 83% and 93%. Twenty-two patients experienced peripheral neuropathy of any grade, and two had grade 3 neuropathy. The combination of bortezomib with R-CHOP is effective for indolent NHL, and we plan to evaluate therapies incorporating novel proteasome inhibitors in future studies in NHL.

In a phase I clinical trial of Venetoclax in patients with t(11;14) relapsed/refractory MM, 40% of the patients treated achieved an objective response(1). While this response rate with a single agent in MM is impressive, it demonstrates that t(11;14) is not an optimal biomarker for response to venetoclax. Functional profiling of BCL2 family members has been shown to predict responses to therapy in myeloma and other diseases(2). Therefore, we set out to determine how ex vivo sensitivity to venetoclax corresponds to clinical response and resistance.

Venetoclax (ABT-199), a specific inhibitor of the anti-apoptotic protein Bcl-2, is currently in phase I clinical trials for multiple myeloma. The results suggest that venetoclax is only active in a small cohort of patients therefore we wanted to determine its efficacy when used in combination. Combining venetoclax with melphalan or carfilzomib produced additive or better cell death in four of the five cell lines tested. The most striking results were seen with dexamethasone (Dex). Co-treatment of human myeloma cell lines and primary patient samples, with Dex and venetoclax, significantly increased cell death over venetoclax alone in four of the five cell lines, and in all patient samples tested. The mechanism by which this occurs is an increase in the expression of both Bcl-2 and Bim upon addition of Dex. This results in alterations in Bim binding to anti-apoptotic proteins. Dex shifts Bim binding towards Bcl-2 resulting in increased sensitivity to venetoclax. These data suggest that knowledge of drug-induced alterations of Bim-binding patterns may help inform better combination drug regimens. Furthermore, the data indicate combining this novel therapeutic with Dex could be an effective therapy for a broader range of patients than would be predicted by single-agent activity.