Daratumumab and its use in the treatment of relapsed and/or refractory multiple myeloma

Daratumumab gained initial US FDA approval as fourth-line therapy among relapsed and/or refractory multiple myeloma (RRMM) patients who have received at least three prior lines of therapy, including a proteasome inhibitor (PI) and immunomodulatory drug (IMiD), or who are double refractory to a PI and an IMiD. Further combination trials of daratumumab led to FDA approvals in combination with bortezomib and dexamethasone or lenalidomide and dexamethasone for multiple myeloma patients who have received at least one prior therapy. The most recent expansion of the FDA approval of daratumumab comes in combination with pomalidomide and dexamethasone for patients with multiple myeloma that have received ≥2 prior lines of therapy including lenalidomide and a PI. The current manuscript reviews data supporting the efficacy and safety of daratumumab in RRMM.

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.

Triplet vs. doublet drug regimens for managing multiple myeloma

INTRODUCTION

Multiple Myeloma (MM) is a complex and heterogeneous plasma cell disorder. Sub-clones present before therapy and clonal evolution during therapy make this disease more resistant and finally refractory. These findings make us aware of the difficulty to target MM with few agents. Multi-drugs therapies allow us to target more pathways and more sub-clones both at diagnosis and in advanced disease.

AREAS COVERED

In this review, the authors focus on the effectiveness and tolerability of three drug regimens (triplet) in comparison with two drug regimens (doublet) and discuss their implications in the present and future of MM therapy.

EXPERT OPINION

It has been demonstrated that triplet regimens are better than doublet in terms of response rate and PFS in newly diagnosed, relapsed-refractory MM and in most patient subgroups. Whether this translates into OS improvement needs further demonstration. However, achievement of MRD negativity in most newly diagnosed and, firstly, in a consistent proportion of relapsed-refractory MM patients is very encouraging in this respect. However, not all patients are able to tolerate all triplet combinations; therefore, the choice should be based on patient characteristics, besides disease features. Finally, cost of triplets may be an important limitation in some countries.