Subcutaneous Daratumumab Is Non-Inferior in Asian Patients, Though Toxicities Persist

An analysis of Asian patients with multiple myeloma found that treatment with subcutaneous daratumumab (DARA SC) was non-inferior to intravenous daratumumab (DARA IV) in this population.

This data comes from a subgroup analysis of the phase 3 COLUMBA study, a head-to-head analysis of DARA SC versus IV in relapsed/refractory patients. Their findings were published in the Annals of Hematology.

Efficacy in Heavily Pre-Treated Patients

In total, 67 Asian patients were included in the analysis, including 30 who received DARA SC 1,800-mg and 37 who received DARA IV 16 mg/kg. Patients were either pre-treated with ≥3 prior lines of therapy, including a proteasome inhibitor and an immunomodulator, or were refractory to two prior treatments. The primary endpoints were overall response rate (ORR) and maximum trough concentration. Other endpoints included infusion-related reactions, progression-free survival (PFS), and patient-reported satisfaction. The study also included a Japanese-only subgroup of 42 patients (DARA SC, n = 18; DARA IV, n = 24).

The ORR in the overall cohort was 66.7% for DARA SC and 43.2% for DARA IV. In the Japanese-only subgroup, the ORR was 61.1% and 54.2% for SC versus IV, respectively. Maximum trough concentration was comparable between treatment groups for both the Asian cohort and the Japanese-only subgroup. Patient satisfaction, recorded via the Cancer Therapy Satisfaction Questionnaire, was found to generally favor SC administration.

High Incidence of Cytopenia

There were high rates of grade ≥3 cytopenia reported in both treatment groups in the overall patient cohort. This high toxicity was also seen in the Japanese DARA SC subgroup. The authors note that incidence of cytopenia was higher than what was recorded in the global COLUMBA population and occurred primarily in patients with low body weight. There was no treatment discontinuation due to cytopenia.

In conclusion, the authors wrote, “In conclusion, DARA SC 1800-mg flat dose was comparable to DARA IV 16 mg/kg, with no new safety concerns, in Japanese, Korean, and Taiwanese patients. Although the analyses in this report are limited by small patient numbers, the efficacy and safety of DARA SC in Asian patients overall and of low bodyweight were consistent with those of the global COLUMBA population.”