Efficacy signals have been shown in 100% of patients with metastatic prostate cancer treated with a new formulation of cabazitaxel.
Treatment with the enhanced version of cabazitaxel, DEP cabazitaxel, has shown 1 or more efficacy signals in all evaluable patients with metastatic prostate cancer undergoing treatment in a phase 2 study, according to interim findings announced in a press release by Starpharma Holdings Group.
Although DEP cabazitaxel is investigational, the traditional formulation of the drug is the most widely used agent for the treatment of advanced prostate cancer worldwide. In the United States, the FDA warning label for cabazitaxel notes neutropenia and severe hypersensitivity which are related to the polysorbate-80 detergent in the drug. The new formulation, DEP cabazitaxel is free of polysorbate-80 and therefore may be a safer option.
According to the interim findings, 64% of the patients with metastatic prostate cancer treated with DEP cabazitaxel who had a measurable lesion experienced prolonged stable disease and significant reductions in tumor size for up to 36 weeks. Of those with assessable prostate-specific antigen (PSA) tumor biomarker levels, 90% had a reduction in PSA with DEP cabazitaxel, and more than half of the patients had at least a 50% reduction in PSA.
Improvement in lesions was shown in 80% of the patients who had secondary bone disease at baseline. Further, 56% of patients who were evaluable for all 3 measures had responses in all 3 areas.
In terms of safety, DEP cabazitaxel showed significantly less severe bone marrow toxicity, lower rates of severe neutropenia, and no cases of neutropenic sepsis compared with traditional cabazitaxel. The results also showed that investigators did not need to administer prophylactic corticosteroids and antihistamines because the investigational agent is polysorbate 80-free. It was noted that avoiding long-term steroid use is especially important for the subgroup of patients who had poor bone health.
"The trial results to date for DEP® cabazitaxel in heavily pre-treated prostate cancer patients are highly encouraging and indicate the potential of the product compared to standard cabazitaxel. The anti-cancer activity, together with less myelosuppression than standard cabazitaxel and a generally well-tolerated safety profile, mean this novel form of dendrimer-enhanced cabazitaxel represents a useful option for prostate cancer patients, including in older patients in whom DEP® cabazitaxel has been particularly well-tolerated, said Anthony Joshua, BSc (Med), MBBS, PhD, FRACP, professor at St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, in a press release.
The interim results are especially significant considering that the majority of patients enrolled had late-stage prostate cancer and had failed multiple anti-cancer treatments including systemic therapy, surgery, and radiation therapy.
The study of patients with solid tumors is ongoing and thus far 51 patients have been recruited across all cancer types. The trial is being conducted at multiple sites in the United Kingdom and Australia. Investigators also plan to recruit a small number of additional patients with ovarian and gastroesophageal cancer, and the agent has shown promising efficacy signals in these tumor types. Full results for the trial will be reported in the near future.
Starpharma releases positive DEP® phase 2 interim results in prostate cancer. News release. Starpharma Holdings, Inc. Novmber 26, 2021. Accessed November 29, 2021. https://www.starpharma.com/news/639