Starpharma announced additional results from the mCRPC cohort of its Phase 2 DEP® cabazitaxel trial, following completion of dosing in this cohort. Treatment with DEP® cabazitaxel showed a number of key advantages compared to published data for conventional cabazitaxel, including superior efficacy, as measured by longer PFS, and a lower incidence of key side effects, despite this patient cohort being relatively more heavily pre-treated. The new data for DEP® cabazitaxel was presented in a scientific poster at the ESMO 2022 Congress in Paris, France, by Principal Investigator, Professor Robert Jones of the Velindre Cancer Centre in Wales.

Twenty-five patients with metastatic castration-resistant prostate cancer were enrolled in this cohort across five trial sites in the UK and Australia. Trial participants received an intravenous infusion of DEP® cabazitaxel every 21 days, repeated for up to 12 cycles. The median time on study was 18.4 weeks.

All patients enrolled in this cohort had already been heavily pre-treated before entering the study, having previously received an average of 4 other cancer treatment types, in addition many have also had surgery and radiation. On average, patients enrolled in this study had already received more than 70 cycles/months of other treatments. Notably, 96% of patients in this trial cohort had also previously received related chemotherapies (taxanes), including docetaxel and/or conventional cabazitaxel (Jevtana®).

This level of pre-treatment is important to note because patients with this high level of prior cancer treatment would not be expected to respond as well to further similar therapies. Highly encouraging anti-tumour activity for DEP® cabazitaxel, including a radiological partial response (PR) for more than 45 weeks, and stable or improved secondary metastatic bone disease for up to 45 weeks; Median progression-free survival (PFS) of 3.9 months2 for DEP® cabazitaxel which is more than 30% longer than published PFS data for standard cabazitaxel (2.9 months3) at the same dose; 100% of evaluable DEP® cabazitaxel patients achieved a response in at least 1 measure of efficacy (soft tissue disease [stable disease (SD) or PR], prostate specific antigen (PSA), and/or bone disease); 90% of DEP® cabazitaxel patients evaluable for a PSA response achieved a reduction in PSA, and 52% achieved a PSA reduction of 50% or more from baseline; 83% of DEP® cabazitaxel patients evaluable for secondary bone disease experienced an improvement or no progression; 68% of DEP® cabazitaxel patients evaluable for 2 or 3 efficacy measures achieved a response for all evaluable measures (soft tissue disease [SD or PR], PSA, and bone disease); No DEP® cabazitaxel patients required routine steroid pre-medication or daily oral steroid and only 2 patients required prophylactic G-CSF 4; and DEP® cabazitaxel was generally well-tolerated, with TRAEs similar to those observed with standard cabazitaxel (Jevtana®).