OncoGenex Receives FDA Approval for Amendment of Phase 3 AFFINITY Protocol

OncoGenex Pharmaceuticals Inc. (NASDAQ:OGXI) announced that its has received FDA approval for the proposed amendment to the Phase 3 AFFINITY protocol and statistical analysis plan.

As quoted in the press release:

The amendment includes the addition of a co-primary endpoint designed to prospectively evaluate the survival benefit of custirsen in men who are at increased risk for poor outcomes when treated with cabazitaxel for metastatic castrate-resistant prostate cancer (CRPC).

The FDA is in agreement with plans for prospectively defining a poor prognostic subpopulation in the Phase 3 AFFINITY trial. OncoGenex, in collaboration with study investigators, has defined a simple 5-criteria characterization for poor prognosis in prostate cancer based on the Phase 3 SYNERGY trial, which includes: poor performance status, elevated prostate specific antigen (PSA), elevated lactate dehyrdogenase (LDH), decreased hemoglobin, and the presence of liver metastasis. Patients with poor prognosis will be identified as having 2 or more of these 5 well-recognized high-risk criteria. The proposed change for AFFINITY is also consistent with custirsen’s mechanism of action, since custirsen was designed to address treatment resistance which may be more prevalent in this subpopulation.

In the revised statistical analysis plan for the AFFINITY trial, the hypothesized hazard ratio (HR) for the poor prognosis subpopulation is specified to be 0.69 with the critical HR ≤ 0.778. The hypothesized HR for the intent-to-treat patients (ITT population) remains unchanged as 0.75 with the critical HR ≤ 0.820.

Cindy Jacobs, PhD, MD, chief medical officer and executive vice president of OncoGenex, commented:

There are limited effective treatment options for men with metastatic CRPC who have risk factors for poor outcomes and who fall into a poor prognosis category. Recent findings from the SYNERGY trial showed a significant survival benefit in this group of patients. We have applied this key insight from the SYNERGY trial to the AFFINITY protocol to better evaluate this vulnerable subpopulation of men who have poor prognosis and shorter survival time.

Click here to read the full OncoGenex Pharmaceuticals Inc. (NASDAQ:OGXI) press release.