In patients with advanced solid tumours, is an autologous cancer vaccine (RGSH4K), safe and tolerable, and can a biologically active dose be identified?

The single centre, open label, first-in-human Phase 1 study was designed to evaluate the safety and tolerability of RGSH4K and to identify the biologically active dose(s) to take into future trials. In this study,12 patients, heavily pretreated with chemotherapy or radiotherapy, with various advanced solid tumours received RGSH4K in 3 dose cohorts. A total of 3 vaccines were administered in the treatment phase, given at 3-week intervals, and patients had the option to continue dosing in an extension phase. All dose levels were safe and well tolerated, achieving the safety primary endpoint. There were no dose limiting toxicities and no serious adverse events related to the vaccine. Injection site reactions were the most common adverse event related to RGSH4K administration. RGSH4K also showed encouraging signs of immune stimulation in some patients, as demonstrated by changes in cancer markers, immune cells and cytokines. This immune stimulation was seen in one or more patients at all three dose levels. Preliminary indications of anti-tumour activity were seen in some patients.