Utilizing an interim futility analysis of the OVAL study (VB-111-701/GOG 3018) for potential reduction of risk: A phase III, double blind, randomized controlled trial of ofranergene obadenovec (VB-111) and weekly paclitaxel in patients with platinum resistant ovarian cancer.

OBJECTIVE: Report the results from a preplanned interim analysis of a phase III, double blind, randomized controlled study of ofranergene obadenovec (VB-111), a targeted anti-cancer gene therapy, in combination with paclitaxel in patients with platinum resistant ovarian cancer (PROC). METHODS: The OVAL (NCT03398655) study is an on-going study where patients are randomly assigned in a 1:1 ratio to weekly paclitaxel 80 mg/m2 with VB-111 or placebo. The protocol specifies a pre-planned unblinded futility interim analysis of CA-125 response per GCIG criteria in the first 60 evaluable patients. The futility rule determined for this analysis was that the response rate of VB-111 must be greater than the response rate of placebo by at least 10% in order to continue the study. Coincident with the interim analysis, the blinded CA-125 response rate was estimated as a proportion of the first 60 evaluable patients with CA-125 response per GCIG criteria. Post-treatment fever is provided as a possible surrogate marker of VB-111 therapy activity. RESULTS: The median age of the evaluable patients was 62 years (range 41-82); 97% had high-grade serous cancer; 58% had been treated with 3 or more previous lines of therapy, 70% received prior anti-angiogenic treatment, 43% received prior PARP inhibitors. CA-125 response in the VB-111 and weekly paclitaxel treated arm met the pre-specified interim criterion of an absolute advantage of 10% or higher compared to the control. Blinded results show a 53% CA-125 response rate (32/60) with 15% complete response (n=9). Assuming balanced randomization and an absolute advantage of 10% or higher to the VB-111 arm, it may be deducted that the response in the VB-111 treatment arm is 58% or higher. Among patients with post-treatment fever, the CA-125 response rate was 69%. CONCLUSIONS: At the time of the interim analysis, response rate findings are comparable to the responses seen in a similar patient population in the phase I/II study. The independent data and safety monitoring committee (iDSMC) recommended continuing the OVAL trial as planned. No new safety signals were identified.

Ofranergene Obadenovec (Ofra-Vec, VB-111) With Weekly Paclitaxel for Platinum-Resistant Ovarian Cancer: Randomized Controlled Phase III Trial (OVAL Study/GOG 3018).

PURPOSE: To evaluate the addition of ofranergene obadenovec (ofra-vec, VB-111), a novel gene-based anticancer targeted therapy, to once a week paclitaxel in patients with recurrent platinum-resistant ovarian cancer (PROC). METHODS: This placebo-controlled, double-blind, phase III trial (ClinicalTrials.gov identifier: NCT03398655) randomly assigned patients with PROC 1:1 to receive intravenous ofra-vec every 8 weeks with once a week IV paclitaxel or placebo with paclitaxel until disease progression. The dual primary end points were overall survival (OS) and progression-free survival (PFS) as assessed by Blinded Independent Central Review. RESULTS: Between December 2017 and March 2022, 409 patients were randomly assigned. The median PFS was 5.29 months in the ofra-vec arm and 5.36 months in the control arm, hazard ratio (HR) 1.03 (CI, 0.83 to 1.29; P = .7823). The median OS with ofra-vec was 13.37 months versus 13.14 months, HR 0.97 (CI, 0.75 to 1.27; P = .8440). Objective response rates (ORRs) per RECIST 1.1 were similar in both arms: 28.9% with ofra-vec versus 29.6% with control. In both treatment arms, response to CA-125 was a substantial prognostic factor for both PFS and OS. In the ofra-vec arm, the HR in CA-125 responders compared with that in nonresponders for PFS was 0.2428 (CI, 0.1642 to 0.3588), and for OS, the HR was 0.3343 (CI, 0.2134 to 0.5238). Safety profile was characterized by common transient flu-like symptoms such as fever and chills. CONCLUSION: The addition of ofra-vec to paclitaxel did not improve PFS or OS. The PFS and ORR in the control arm exceeded the results that were anticipated on the basis of the AURELIA chemotherapy control arm. CA-125 response was a substantial prognostic biomarker for PFS and OS in patients with PROC treated with paclitaxel.