Human Reovirus Shows Mixed Results as Ovarian Cancer Treatment

Reloysin reduces tumor burden

Promising data have been reported from an ongoing phase 2 trial of Reolysin (Oncolytics Biotech), a proprietary formulation of the human reovirus, in combination with paclitaxel in women with ovarian cancer.

The randomized study is comparing paclitaxel monotherapy with paclitaxel plus Reolysin in patients with persistent or recurrent, ovarian, fallopian tube, or primary peritoneal cancer. Patients received paclitaxel on days 1, 8, and 15 of each 28-day treatment cycle, with either Reolysin (the test arm; n = 54) or placebo (the control arm; n = 54) administered on days 1 through 5. The study’s primary objectives are progression-free survival (PFS) and toxicity. Secondary objectives include median overall survival (OS) by treatment group, median PFS by treatment group, and tumor response, as measured by Response Evaluation Criteria in Solid Tumors (RECIST) and cancer antigen 125 (CA-125) levels. The study is being sponsored by the National Cancer Institute. 

An intention-to-treat analysis of tumor response, as assessed by CA-125 antigen levels, showed significantly higher full response rates and stable disease or better rates in the test arm compared with the control arm. The rate of full responses in the test arm was 9.3% compared with 1.9% in the control arm (P = 0.0196). The rate of stable disease or better in the test arm was 44.4% compared with 24.1% in the control arm (P = 0.0096).

Response rates, as measured by RECIST, were determined in patients with measurable disease (68 of the 108 patients). The proportion of patients responding in the test arm was 17% compared with 20% in the control arm.

An analysis of PFS, stratified by measurable disease and the platinum-free interval (test arm: n = 54, 43 events [progressions]; and control arm: n = 54, 48 events), was performed and demonstrated a median PFS of 4.4 months for the test arm and 4.3 months for the control arm.

An interim analysis of OS (test arm: n = 54, 32 events [deaths]; and control arm: n = 54, 32 events) was performed and demonstrated a median OS of 12.9 months for the test arm and 15.0 months for the control arm. The OS was an interim analysis as 44 patients out of a total of 108 patients (41%) were alive at the time of the analysis. Given the number of patients still alive in the test and control arms with current survival less than the median, final median OS results are expected to change.

Source: Oncolytics Biotech; March 21, 2016.