Pilot study shows promise for immunotherapy in advanced ovarian cancer

A 2-step immunotherapy and combination chemotherapy protocol is feasible for patients with advanced, recurrent ovarian cancer, according to the results of a small pilot study by University of Pennsylvania researchers. Published in OncoImmunology and supported by the National Cancer Institute, the report documented response in women whose tumors previously had failed to respond to bevacizumab and cyclophosphamide.

Six patients aged 46 to 69 were included in the study, all of whom received bevacizumab and metronomic cyclophosphamide plus vaccine. Following treatment, 4 of the patients (66%) had clinical benefits from the combination therapy: 2 experienced objective partial remissions and 2 had stable disease.

In the study, patients received a vaccine composed of dendritic cells harvested from them that had been primed by exposure to extracts from their own tumors, followed by chemotherapy with bevacizumab and cyclophosphamide. Of the 4 women who had an antitumor immune response, 1 remains in remission 42 months following vaccine treatment. The other 3 patients went on to receive T-cell transfer after lymphodepleting chemotherapy. In 2 of them, the treatment restored immune response, leading to a complete response in 1 of the women and stable disease in the other. 

Based on these results, the researchers have launched a larger trial to test an improved vaccine platform and an optimized adoptive T-cell transfer protocol, with a target enrollment of 30 women. Whether the therapy will be effective in a large number of ovarian cancer patients remains to be determined but, the authors say, the outcome in the pilot study was promising and the 2-step approach appears safe and well tolerated. The response documented in 1 woman who had previously failed the same chemotherapy, the researchers noted, suggests that the vaccine elicited an antitumor immune response.