Australian biotech company Imugene has revealed positive results from a phase 2 trial of its lead HER2 cancer vaccine in patients with HER2-positive stomach or gastroesophageal junction (GEJ) cancer.
The HER-Vaxx jab is a B-cell activating cancer immunotherapy designed to target tumours that overexpress the HER2/neu receptor in gastric, breast, ovarian, lung and pancreatic cancers.
The phase 2 trial is evaluating HER-Vaxx plus standard of care chemotherapy in patients with metastatic or advanced stomach or GEJ cancer.
The new mid-stage data, presented at the ESMO World Congress on Gastrointestinal Cancer 2021 annual meeting, showed that HER-Vaxx plus chemotherapy resulted in an overall response rate of 50% compared to 29% in patients treated solely with chemotherapy.
In addition, Imugene noted that patients treated with HER-Vaxx had a substantially higher reduction in their tumour sized compared to those treated with chemotherapy alone.
Patients with antibody levels higher than 1050ng/ml also received greater than 50% tumour reduction, with Imugene highlighting that this may serve as a potential biomarker for response.
Previously, Imugene revealed interim analysis results for the phase 2 study, which showed HER2-Vaxx reduced the risk of death by 58.2% compared to chemotherapy alone.
The median overall survival for HER-Vaxx-treated patients in the interim analysis was also higher than the chemotherapy group – 14.2 months versus 8.8 months, respectively.
The interim data also represented a ‘clinical proof-of-concept’ signal for Imugene’s cancer vaccine, highlighting how the jab, when added to chemotherapy, can induce clinically active antibody responses.
Recruitment for the phase 2 trial of HER-Vaxx completed in January 2021, after the independent data monitoring committee (IDMC) recommended a lower number of patients would be needed for study completion.
The IDMC recommendation came following the survival benefit in the interim analysis as well as the favourable safety profile of the vaccine.
Elsewhere in Imugene’s pipeline are a phase 1 triple negative breast cancer vaccine and a phase 1 non-small cell lung cancer vaccine.