DARATUMUMAB, BORTEZOMIB AND DEXAMETHASONE (DVD) VS BORTEZOMIB AND DEXAMETHASONE (VD) IN RELAPSED OR REFRACTORY MULTIPLE MYELOMA (RRMM): EFFICACY AND SAFETY UPDATE (CASTOR)

The Role of Immunotherapy in Non-transplant Eligible Multiple Myeloma

As the global population is aging and survival in multiple myeloma (MM) is increasing, treating older MM patients, redefined as non-transplant eligible (NTE), is becoming more frequent. Yet, treating these patients remains a real challenge especially because of a marked heterogeneity in the population and an increased susceptibility to treatment toxicity. Indeed, the balance between efficacy and safety must be considered at all time throughout the treatment history for these patients. Therefore, younger and older patients were historically treated in a very different way, even though the safety profile of most anti-myeloma drugs has drastically improved over the years. The emergence of immunotherapy (IT) has largely widened the therapeutic options available in MM and above all has allowed a therapy at optimal dose, and therefore optimal activity, for all patients independently of their frailty features, with no increase in safety issues. Among the novel anti-myeloma IT-based agents, anti-CD38 monoclonal antibodies (mAbs) are now becoming the new backbone of treatment for NTE patients, in association with lenalidomide and dexamethasone. Moreover, several new IT-based drugs are currently being developed and investigated either alone or in association; such as new anti-CD38 mAbs, anti-CD38 mAbs with many different combinations, but also the CAR-T cells, bispecific T-cell engager (BiTEs), or antibody drug conjugate (ADC) targeting BCMA. One would expect that immunotherapy will ultimately change and even transform the MM landscape, even for elderly patients. Immunotherapy represents a shift in treatment paradigm in MM as it provides truly efficient drugs with a very favorable safety profile.

Relapsed refractory multiple myeloma: a comprehensive overview

Most patients with relapsed/refractory multiple myeloma (RRMM) have been treated with drug combinations including a proteasome inhibitor (PI) and/or an immunomodulatory drug (IMiD). The goal of therapy for such patients is therefore to achieve disease control with acceptable toxicity and patient-defined decent quality of life. Physicians face a difficult task not only deciding who to treat, but also when to treat and how to treat, utilizing knowledge of previously administered therapies, patient comorbidities, potential adverse events, and patient wishes to make such a critical decision. New drugs and combination regimens are continuously underway thus broadening the options for therapy and giving way to a more individualized approach for patients with RRMM. The integration of novel agents into the treatment paradigm has shifted the perception of multiple myeloma (MM) from an incurable, fatal disease to a manageable, chronic one. This comprehensive review addresses the results and challenges posed by many of the newer agents for the treatment of RRMM. It attempts to propose a universal strategy for optimal therapy decision-making thus answering three simple fundamental questions-when to treat, how to treat, and how long to treat for.

Daratumumab: A Review in Relapsed and/or Refractory Multiple Myeloma

Intravenous daratumumab (DARZALEX^®) is a first-in-class human IgG1κ monoclonal antibody against CD38 available for use in patients with relapsed and/or refractory multiple myeloma. In phase I/II and II trials and a pooled analysis of these studies, daratumumab monotherapy induced an overall response (partial response or better) in approximately one-third of patients; responses were rapid, deep and durable. An overall survival (OS) benefit was seen with daratumumab monotherapy, including in patients with a minimal response or stable disease. In phase III trials, daratumumab in combination with either bortezomib plus dexamethasone or lenalidomide plus dexamethasone significantly prolonged progression-free survival and induced deep and durable responses compared with bortezomib plus dexamethasone or lenalidomide plus dexamethasone. An OS benefit with daratumumab triple combination therapy is yet to be demonstrated (as the OS data were not mature at the time of the last analysis). Daratumumab was generally well tolerated when used as monotherapy and had a generally manageable tolerability profile when used in combination therapy. Infusion-related reactions (IRRs) were the most common adverse events; these were predominantly grade 1 or 2 and mostly occurred during the first infusion. The most common grade 3-4 adverse events associated with daratumumab triple combination therapy were thrombocytopenia, neutropenia and anaemia. Although final OS data are awaited, current evidence indicates that daratumumab is a valuable addition to the treatment options currently available for patients with relapsed or refractory multiple myeloma.

Efficacy of daratumumab-based therapies in patients with relapsed, refractory multiple myeloma treated outside of clinical trials

Outside of clinical trials, experience with daratumumab-based combination therapies (DCTs) using bortezomib (V)/lenalidomide (R)/pomalidomide (P), and dexamethasone (d) in relapsed/refractory multiple myeloma (RRMM) is limited. We reviewed the outcomes of 126 patients who received ≥ 1 cycle of any DCT. Median age at DCT initiation was 67 (range, 43-93) years. High-risk cytogenetics was present in 33% patients. Median number of prior therapies was 4 (range, 1-14) and time to first DCT from diagnosis was 4.3 years (range, 0.4-13.0). Seventeen (13%) patients were refractory to single agent daratumumab. Fifty-two (41%), 34 (27%), 23 (18%), and 17 (14%) received DPd, DRd, DVd and "other" DCTs, respectively. Overall response rate was 47%. Median follow-up was 5.5 months (95% CI, 4.2-6.1). Median progression-free survival (PFS) was 5.5 months (95% CI, 4.2-7.8). Median overall survival was not reached (NR) with any regimen. Median PFS (months) was worst for penta-refractory MM (n = 8) vs quadruple refractory MM (n = 18) and others (n = 100) (2.2 [95% CI, 1-2.4] vs 3.1 [95% CI, 2.1-NR] vs 5.9 [95% CI, 5.0-NR]; P < .001); those who were refractory to ≥1 agents used in the DCT vs others (4.9 [95% CI, 3.1-6.0] vs 8.2 [95% CI, 4.6-NR]; P = .02); and those who received >2 prior therapies vs others (5.0 months [95% CI, 3.7-5.9] vs NR [95% CI, NR-NR]; P = .002). Non-hematologic toxicities included infections (38%), fatigue (32%), and infusion reactions (18%). Grade 3 or higher hematological toxicities were seen in 41% of patients. DCTs are effective in RRMM. ORR and PFS in heavily pretreated patients are lower than those reported in clinical trials.