Part 1 of the CASSIOPEIA phase-3 study compared the addition of daratumumab to bortezomib, thalidomide, and dexamethasone (D-VTd) induction/consolidation with VTd alone in transplant- eligible patients with newly diagnosed multiple myeloma.
The results of the study showed superior efficacy of D-VTd over VTd alone in combination with autologous stem cell transplantation (ASCT), which led to the regulatory approval of the treatment.
The CASSIOPEIA part 2 interim analysis aimed to compare daratumumab maintenance (16 mg/kg every 8 weeks) with observation treatment in all 886 responders from part 1 of the study.
The results of the interim analysis, presented at EHA 2021, showed that patients maintained with daratumumab exhibited significantly longer progression-free survival (PFS) compared to the observation treatment arm.
However, stratification of the patients by induction/consolidation treatment revealed that this benefit only appeared in patients previously treated with VTd in CASSIOPEIA part 1.
Patients who received D-VTd in part 1 and were placed on daratumumab maintenance showed comparable PFS to the observation group.
Furthermore, daratumumab maintenance led to a significantly higher depth of response and no new safety signals were detected.
In summary, daratumumab maintenance is beneficial for patients after ASCT who received VTd induction/consolidation.