Ziopharm Oncology Inc. (NASDAQ:ZIOP) took the opportunity at the 2016 European Society for Medical Oncology Congress in Copenhagen, Denmark, to present preliminary data on Phase 1b/2 clinical study of its breast cancer drug candidate Ad-RTS-hIL-12.
The study of Ad-RTS-hIL-12 as a potential treatment for breast cancer is being carried out at the Memorial Sloan Kettering Cancer Center in New York. Ziopharm said the ongoing study aims to evaluate the efficacy, safety and tolerability of Ad-RTS-hIL-12. The study seeks to test the drug in some 40 women battling locally advanced or metastatic breast cancer.
The data that Ziopharm presented was for study outcome of Ad-RTS-hIL-12 + veledimex. ZIOP explained that Ad-RTS-hIL-12 + veledimex is a gene therapy capable of regulating local expression of IL-12. The company further said that the ability to control production of IL-12 is achieved through adjusting veledimex dosing. Modulating veledimex dosing is important in improving therapeutic outcome of the candidate compared with the standard care.
Keep in mind that Ziopharm is testing Ad-RTS-hIL-12 in patients with all subtypes of breast cancer. Once patients start receiving Ad-RTS-hIL-12, they stop chemotherapy.
During the study, patients received a single cycle of Ad-RTS-hIL-12 + veledimex, with the being able to improve or at least maintain pre-study response.
The study outcome
Ziopharm reported that Ad-RTS-hIL-12 + veledimex triggered the production of IL-12 after 7 days of study. The expression of IL-12 in turn triggered production of IFNγ.
CD8+ T cells and IFNγ were noted to be present after 6 weeks of completing the administration of veledimex. That indicated the ability of Ad-RTS-hIL-12 to produce favorable impact in tumor environment in the long-run. ZIOP said that two patients who received Ad-RTS-hIL-12 + veledimex exhibited durable response lasting 18 to 35 weeks.
The disease control rate (DCR) in all the patients was 44% after 6 weeks of treatment and came to 22% after 12 weeks. On the other hand, overall response rate (ORR) was 11% after 12 weeks of treatment.
Though toxicities were observed in relation to the study, ZIOP said that they reversed after veledimex dosing was discontinued.
“These data provide additional evidence that IL-12 expression and corresponding downstream signaling is activated using Ad-RTS-hIL-12 + veledimex [..],” said Francois Lebel, Chief Medical Officer at ZIOP.
Ziopharm stock eased 5.57% to $5.42 in the last session.