Clinical stage immuno-oncology company Imugene Limited (ASX:IMU) reports that positive interim data from its ongoing Phase 2 study of HER-Vaxx in Her-2/Neu programme showed a reduced risk of death of 58.2% in its chemotherapy group as compared to chemotherapy alone.
Following analysis of interim HER-Vaxx Phase 2 safety and efficacy data, the Independent Data Monitoring Committee (IDMC) reported no safety concerns and viewed this preliminary data as strongly in favour of a HER-Vaxx survival effect.
The interim analysis results from this clinical proof-of-concept study, which was designed with a specified 1-sided false positive probability of 0.10, showed twice as many patients survived on the HER-Vaxx plus SOC chemotherapy treatment arm compared to the SOC chemotherapy control arm.
This translated into an overall survival HR of 0.418 (80% 2-sided CI: 0.186, 0.942) with a statistically significant 1-sided p-value of 0.083. There was no difference in safety events between the two treatment arms, suggesting that HER-Vaxx does not add toxicity to SOC chemotherapy.
MD and CEO, Leslie Chong, said the longest HER-Vaxx treated patient remains on therapy and progression-free 16.3 months after dosing.
Historical data from the ToGA Phase 3 study which examined the effect of Herceptin plus chemotherapy versus chemotherapy alone in advanced gastric cancer, had an overall survival HR of 0.74 for the intent-to- treat analysis of the same patient population of HER2 overexpressing patients included in the HER-Vaxx Phase 2 study.
The IDMC provided guidance that it is scientifically and ethically appropriate to reduce the overall number of patients required to complete the study given the strong signal observed in the data.
I am delighted to report that we have achieved this significant milestone for patients with advanced gastric cancer,” Mrs Chong said.
“I am excited that the interim analysis favoured the survival outcome for HER-Vaxx and the IDMC suggested to shorten the study by lowering the number of patients.
“This data represents a clinical proof-of-concept for HER-Vaxx and supports our B-cell activating immunotherapy platform. I look forward to updating the market as the data matures.”
Imugene’s HER-Vaxx is a B-cell peptide cancer immunotherapy designed to treat tumours that over-express the HER-2/neu receptor, such as gastric, breast, ovarian, lung and pancreatic cancers.
The immunotherapy is constructed from several B cell epitopes derived from the extracellular domain of HER-2/neu. It has been shown in pre-clinical studies, in Phase I and now Phase 2 studies to stimulate a potent polyclonal antibody response to HER-2/neu, a well-known and validated cancer target.
The Phase 2 HER-Vaxx study is designed to measure the efficacy, safety and immune response in 68 patients with metastatic gastric cancer overexpressing the HER-2 protein.
The study is randomised into two arms of either HER-Vaxx plus standard-of-care chemotherapy or standard-of- care chemotherapy alone.
The primary endpoint is overall survival and secondary endpoint will be progression-free survival. Safety, tolerability and immune response will also be measured.
The Phase 2 trial is being conducted at multiple sites across Eastern Europe and India where clinicians have difficulty accessing approved antibody treatments.