Efficacy and safety of pomalidomide and low-dose dexamethasone in Chinese patients with relapsed or refractory multiple myeloma: a multicenter, prospective, single-arm, phase 2 trial

Background Pomalidomide in combination with dexamethasone has demonstrated positive results in patients with relapsed or refractory multiple myeloma (RRMM), but no data are available in China. We conducted a multicenter, single-arm trial to examine the efficacy and safety of bioequivalent generic pomalidomide plus low-dose dexamethasone in Chinese RRMM patients. Methods Adult (≥ 18 years of age) RRMM patients who progressed after at least two previous treatments, including bortezomib and lenalidomide, were eligible. Pomalidomide was given orally at 4 mg/day on days 1 to 21 of a 28-day cycle. Dexamethasone was given at 40 mg/day (either orally or intravenously; 20 mg/day at 75 years or older) on days 1, 8, 15, and 22 of each cycle. Treatment continued until disease progression or intolerable adverse events (AEs). The primary end point was objective response rate (ORR). Results Seventy-four patients were enrolled between February 2017 and February 2019. All patients had progressed within 60 days of their last therapy. 74.3% of the patients were resistant to lenalidomide, 31.1% had renal insufficiency and 33.8% had high-risk cytogenetic RRMM. The median follow-up duration was 33.0 months (range 31.1–34.8 months). The ORR was 37.8% in the overall analysis, 32.7% in lenalidomide-refractory patients, 36.0% in patients with high-risk cytogenetics and 34.8% in RRMM patients with renal impairment. The median progression-free survival was 5.7 months (95% CI 3.7–8.8 months). The median overall survival was 24.3 months (95% CI 14.4–41.1 months). The most common grade 3 and 4 treatment-emergent adverse events (TEAEs) were neutropenia (63.5%), leukopenia (37.8%), thrombocytopenia (28.4%), and anemia (31.1%). Pulmonary infection (27.0%) was the most frequent grade 3 and 4 nonhematologic TEAE. No previously unreported AEs were observed. No venous thromboembolism was reported. Conclusions Pomalidomide in combination with low-dose dexamethasone is effective and safe in Chinese RRMM patients. Trial registration The study is registered at Chinese Clinical Trial Registry (ChiCTR) ( ChiCTR-OIC-17013234 , first registered on 03/11/2017).