Pomalidomide in combination with bortezomib and dexamethasone  (PVd) may lead to significant prolongations in progression-free survival (PFS) among patients with relapsed/refractory multiple myeloma (RRMM) resistant to lenalidomide compared to bortezomib and dexamethasone (Vd) alone, according to an oral presentation at the American Society of Clinical Oncology (ASCO) Annual Meeting on Friday, June 1.1

Findings from previous studies have found that pomalidomide treatment led to the inhibition of lenalidomide-resistant cells and improved overall survival in lenalidomide-refractory patients. Paul G. Richardson, MD, added, “lenalidomide is an established therapy in newly diagnosed multiple myeloma; therefore, patients for whom lenalidomide is no longer a treatment option represent a clinically relevant population with an unmet need.”

In the phase 3 OPTIMISMM study (ClinicalTrials.gov Identifier: NCT01734928) researchers randomly assigned 559 patients with RRMM 1:1 to receive Vd or PVd. Eligible patients had been previously treated with 1 to 3 lines of therapy, of which 1 must have been lenalidomide; approximately 70% of the study population was lenalidomide-refractory. Baseline characteristics were generally well-balanced between the treatment arms.

After a median follow-up of 16 months, patients in the PVd arm had a median PFS of 11.2 months compared with 7.1 months among patients who received Vd only (hazard ratio [HR], 0.61; 95% CI, 0.49-0.77; P < .0001), which represented a 39% reduction in the risk of progression or death.

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Of the patients who had received only 1 prior line of therapy, the median PFS was significantly longer among patients in the PVd arm (20.73 vs 11.63; HR, 0.54; 95% CI, 0.36-0.82; P = .0027); a 46% reduction in the risk of progression and death.

The overall response rate (ORR), defined as at least partial response, was 82.2% and 50.0% among patients in the PVd group and Vd group, respectively; 52.7% of patients in the pomalidomide arm had a very good partial response compared with 18.3% among patients in the non-pomalidomide arm. The ORR among patients who received only 1 previous line of therapy was 90.1% in the PVd arm and 54.8% in the Vd arm.

Median time-to-response was 0.9 months and 1.4 months among patients in the PVd arm and Vd arm, respectively, and the median duration of response was 13.4 months and 10.9 months, respectively.

Patients in the PVd arm also had a significantly longer time-to-next-treatment (TTNT) with 22.24 months compared with 8.51 months among patients who received Vd only (HR, 0.42; 95% CI, 0.33-0.54; P < .001). A PFS benefit of PVd was sustained in the next line of therapy (22.44 months vs 16.95 months; HR, 0.76; 95% CI, 0.59-0.99; P = .041).

The most frequently reported grade 3 to 4 adverse effects included neutropenia, infections, and thrombocytopenia.

Data regarding overall survival were not yet mature at the time of analysis.

Dr Richardson concluded that “these reports support the use of PVd in first relapse in patients with RRMM and prior exposure to lenalidomide. Future directions include analysis of correlatives, minimal residual disease, and quality of life.”

Reference

This article originally appeared on Cancer Therapy Advisor