Isatuximab combined with standard chemotherapy in multiple myeloma leads to more patients achieving minimal residual disease negativity
Adding isatuximab to standard induction chemotherapy in those with multiple myeloma (MM) produces superior minimal residual disease negativity. This was the finding of a study by a team from the University Hospital Heidelberg and National Center of Tumour Diseases, Heidelberg, Germany, and presented at ASH 2021.
In newly-diagnosed MM patients, the combination, lenalidomide / bortezomib/ dexamethasone (RVd) has become one of the most widely used induction regimens. Moreover, the high level of expression of CD38 antigen on plasma cells and has become an important target for the treatment of MM with anti-CD38 monoclonal antibodies-CD38 such as isatuximab.
The German team presented the first primary endpoint data of the randomised, open-label, multi-centre, Phase III GMMG-HD7 trial, which was designed to compare RVd without or with the isatuximab (isa) with respect to the rate of minimal residual disease (MRD) negativity (i.e., no evidence of cancer in the bone marrow) in patients with transplant-eligible MM. The primary endpoint of the trial was MRD negativity assessed by next-generation flow after induction and the secondary endpoint was the rate of complete response (CR) after induction as well as safety data.
A total of 658 patients with a median age of 58 years, began induction (RVd: 329/328 and Isatuximab-RVd: 331/330) and baseline characteristics were well balanced between treatment arms. On induction, 35 (10.6%) and 18 (5.4%) patients discontinued treatment in the RVd vs. Isa-RVd arms (p = 0.02). Among these, 8 (2.4%, RVd) vs. 7 (2.1%, Isa-RVd) patients discontinued induction due to adverse events (AE). 293 (89.1%) vs. 312 (94.3%) patients in the RVd vs. Isa-RVd arms continued further study treatment after induction.
MRD negativity rates after induction were 35.6% vs. 50.1% (RVd vs. Isa-RVd), giving an odds ratio, OR = 1.83 (95% CI 1.34-2.51, p<0.001) in favour of isatuximab. While the rates of CR after induction did not yet differ between the RVd vs. Isa-RVd arms (21.6% vs. 24.2%, p = 0.46), the rate of very good partial response or better was significantly higher in the Isatuximab-RVd arm (60.5% vs. 77.3%, p < 0.001). The rates of progressive disease were 4.0% (RVd) vs. 1.5% (Isa-RVd).
With respect to safety there was no significant difference with at least one adverse event (grade ≥3) on induction which occurred in 61.3% (RVd) and 63.6% (Isa-RVd) of patients (p = 0.57). Rates of serious adverse events on induction were also between the two groups (36.3% vs. 34.8%, RVd vs. Isa-RVd p = 0.75).
The authors concluded that the GMMG-HD7 trial demonstrated superiority of MRD negativity rates after induction by adding isatuximab to RVd. They added that the trial is ongoing, including analyses post autologous transplantation, which is followed by a second randomisation to compare the efficacy of the addition of Isa to lenalidomide maintenance.
Goldschmidt H et al. Addition of Isatuximab to Lenalidomide, Bortezomib and Dexamethasone As Induction Therapy for Newly-Diagnosed, Transplant-Eligible Multiple Myeloma Patients: The Phase III GMMG-HD7 Trial. ASH conference 2021