Board Recommends Continued Dosing of Patients in Phase 2 Study of Immunotherapy for Advanced Ovarian Cancer

The Data Safety Monitoring Board (DSMB) has universally recommended the continuation of the phase 1 and 2 OVATION 2 study following a pre-planned interim safety review of 55 patients with advanced (stage 3 or 4) ovarian cancer treated with a dose of 100 mg/m2 of GEN-1, an IL-12 gene-mediated immunotherapy. Further, they determined that safety is satisfactory with an acceptable risk and benefit, with patients tolerating up to 17 doses of GEN-1 during a course of treatment that lasts up to 6 months, according to a press release.

The OVATION 2 study combines GEN-1 with standard-of-care neoadjuvant chemotherapy (NACT) in patients newly diagnosed with stage 3 and 4 ovarian cancer. NACT is designed to shrink the cancer as much as possible for optimal surgical removal after 3 cycles of chemotherapy. Following this, patients undergo interval debulking surgery, followed by 3 additional cycles of chemotherapy to treat any residual tumor.

The study was designed with an 80% confidence interval for an observed progression-free survival hazard ratio of 0.75, or a 33% improvement in risk for cancer progression when comparing the treatment arm (NACT + GEN-1) with the control arm (NACT only), according to the press release.

In addition, more than 50% of the projected 110 patients have been enrolled in the OVATION 2 study, and the interim clinical data from the first 36 patients who have undergone interval debulking surgery include:

• Out of the 36 patients, 20 were treated with GEN-1 at a dose of 100 mg/m2 plus NACT, with 80% having a complete tumor resection (R0), which specifies a microscopically margin-negative resection in which no gross or microscope tumor remains in the tumor bed.
• Sixteen patients were treated with NACT only, with 56% having R0 restrictions.

The objective response rate (ORR)—as measured by Response Evaluation Criteria in Solid Tumors criteria for the 16 patients treated with NACT—was comparable for the 20 patients treated with GEN-1 at a dose of 100 mg/m2 plus NACT, with both groups demonstrating an approximate 80% ORR.

“These findings show a consistent dose-dependent clinical response in both surgical outcome and tumor response, which is further supported by translational data of the tumor microenvironment,” said Nicholas Borys, MD, in the press release. “Continuing our clinical research program at the 100 mg/m2 dose in patients with advanced-stage ovarian cancer holds promise and is strongly encouraged by our study investigators and medical advisors.”

GEN-1 received FDA Fast Track Designation in February 2021 in advanced ovarian cancer.

REFERENCE

Celsion Reports Data Safety Monitoring Board Recommendation to Continue Dosing Patients in the Phase II Portion of the OVATION 2 Study with GEN-1 in Advanced Ovarian Cancer. Intrado GlobeNewswire. July 19, 2021. Accessed July 28, 2021. https://www.globenewswire.com/news-release/2021/07/19/2264784/0/en/Celsion-Reports-Data-Safety-Monitoring-Board-Recommendation-to-Continue-Dosing-Patients-in-the-Phase-II-Portion-of-the-OVATION-2-Study-with-GEN-1-in-Advanced-Ovarian-Cancer.html