GOG-0186H is a randomized Phase II trial of paclitaxel versus 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 twenty-eight day treatment cycle, with either REOLYSIN® (test arm) or placebo (control arm) administered on days 1 through 5. Approximately 110 patients were enrolled. The primary objectives are progression-free survival and toxicity. The secondary objectives are median overall survival by treatment group, median progression-free survival group, and tumour response as measured by RECIST and CA-125 criteria.
In March 2016, the Company announced response data from the study, with an intent-to-treat analysis of tumour response, as assessed by CA-125 antigen levels, showing statistically significantly higher full response rate and stable disease or better rates in the test arm versus the control arm:
|Full Response||1 (1.85%)||5 (9.26%)||6|
|Partial Response||9 (16.67%)||7 (12.96%)||16|
|Stable Disease||3 (5.56%)||12 (22.22%)||15|
|Progressive Disease||0 (0.00%)||2 (3.70%)||2|
|Indeterminate||16 (29.63%)||13 (24.07%)||29|
|Not Evaluable||25 (46.30%)||15 (27.78%)||40|
Source: GOG Study Summary Report
The rate of full responses in the test arm was 9.26%, compared with 1.85% in the control arm (p = 0.0196). The rate of stable disease or better in the test arm was 44.44%, compared with 24.08% in the control arm (p = 0.0096). The response rates were defined using a modified Rustin’s criteria. CA-125 levels are commonly used in clinical practice to assess response in ovarian cancer patients.
Response rates as measured by RECIST were performed on patients with measurable disease (n = 68 (of 108)). The proportion responding on the test arm was 17% whereas the proportion responding on the control arm was 20%.
An analysis of progression free survival (“PFS”), stratified by measurable disease and 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 overall survival (“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 (41%) patients out of a total of 108 patients were alive at the time of analysis. Given the number of patients still alive on the test and control arms with current survival less than the median, final median OS results are expected to change.
The study is being sponsored by the US National Cancer Institute and conducted by the former Gynecologic Oncology Group (GOG), now incorporated into NRG Oncology. Final results from the study remain pending.