Immunochemotherapy Primed With Oncolytic Vaccinia Virus in Platinum-Resistant Ovarian Cancer
Posted: Wednesday, October 21, 2020
An intraperitoneal oncolytic vaccinia virus, followed by the immunochemotherapy regimen of an intravenous carboplatin doublet with or without bevacizumab, may provide patients with platinum-resistant ovarian cancer an alternative treatment that may reverse platinum resistance. The study, which was presented as a plenary abstract at the 2020 International Gynecologic Cancer Society (IGCS) Annual Global Meeting (Abstract 1308), was conducted by Robert Holloway, MD, of AdventHealth Cancer Institute, Orlando, Florida, and colleagues.
“Virus-induced changes in the tumor microenvironment may explain the apparent clinical reversal of platinum resistance,” the investigators concluded.
The study enrolled 27 patients with platinum-resistant or -refractory ovarian cancer. Patients had a median of four prior treatments, with 52% of patients having platinum-refractory disease and 48% having platinum-resistant disease. After disease progression from recent therapies, patients received 2 days of intraperitoneal oncolytic vaccinia virus, which was followed by a carboplatin doublet with or without bevicizumab. Patients were then maintained with single-agent therapies with or without bevicizumab. Lastly, the researchers acquired biopsies of tumors before and after and virotherapy.
The investigators reported an overall response rate of 54% (95% confidence interval [CI] = 33%–74%), with 2 patients achieving a complete response; 11, a partial response; and 8, stable disease. Progression-free survival was found to be 11 months (95% CI = 6.7–13.0 months), with a 6-month progression-free survival rate of 77%. The CA-125 overall response rate was 85% (95% CI = 65%–96%). A total of 24 patients exhibited preserved or improved status while on the carboplatin doublet with or without bevacizumab. The researchers revealed a post-virotherapy increase of intratumoral infiltration of CD8-positive T cells. This finding was combined with upregulation of STAT1 expression. The authors noted that no patients reported grade 4 adverse events from virotherapy.
Disclosure: No disclosure information for study authors was provided.