Isatuximab add-on to chemotherapy increases minimal residual disease negativity in multiple myeloma

13th December 2021

Isatuximab added to standard therapy in multiple myeloma led to a higher proportion of patients achieving minimal residual disease negativity

Addition of isatuximab to standard induction chemotherapy in patients with multiple myeloma (MM) produces superior minimal residual disease negativity in patients with multiple myeloma. 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, lenalidomide / bortezomib/ dexamethasone (RVd) has become one of the most widely used combination induction regimens. CD38 antigen is highly and uniformly expressed on plasma cells and has therefore become an ideal target for the treatment of MM with anti-CD38 monoclonal antibodies-CD38 such as isatuximab.

The German researchers have now presented the first primary endpoint data of the randomised, open-label, multicentre, Phase III GMMG-HD7 trial, 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) induction therapy 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.

Findings

A total of 658 patients were started induction (RVd: 329/328 and Isatuximab-RVd: 331/330) with a median age of 58 years 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). 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.

Citation

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