ASCO 2021: Interim Analysis of CASSIOPEIA Trial of Daratumumab Maintenance in Myeloma
Posted: Wednesday, June 9, 2021
CASSIOPEIA is a two-part, phase III study in patients with newly diagnosed multiple myeloma who are eligible for transplantation. The combination of the anti-CD38 monoclonal antibody daratumumab with bortezomib, thalidomide, and dexamethasone (VTd) plus autologous stem cell transplant was approved based on the results of CASSIOPEIA Part One. Results from CASSIOPEIA Part Two demonstrate that patients with newly diagnosed multiple myeloma who are eligible for transplant may derive greater benefit from daratumumab maintenance following treatment with VTd than patients who receive observation alone. During the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 8004), Philippe Moreau, MD, of the University Hospital Hôtel-Dieu, Nantes, France, and colleagues shared data from their interim analysis, indicating deeper responses and no new safety signals among patients treated with daratumumab maintenance.
The researchers randomly assigned the 886 patients who achieved at least partial responses in Part One to daratumumab maintenance (n = 442) or observation (n = 444) for up to 2 years. Patients were eligible regardless of induction or consolidation treatment. The median follow-up was 35.4 months.
The median progression-free survival was not reached for patients who received daratumumab compared with 46.7 months for patients who received observation (P < .0001). Similarly, for the daratumumab group, the median time to disease progression was not reached versus 46.7 months for the observation group (P < .0001). A significantly higher number of patients achieved complete responses with daratumumab versus observation (P < .0001). Measurable residual disease (MRD) negativity rates were significantly higher among the daratumumab cohort than the observation cohort (58.6% vs. 47.1%; P < .0001).
The most common adverse events for the daratumumab and observation groups, respectively, were pneumonia (2.5% vs. 1.4%), lymphopenia (3.6% vs. 1.8%), and hypertension (3.0% vs. 1.6%). Overall, 22.7% of patients treated with daratumumab reported serious adverse events, compared with 18.9% of patients under observation.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.