Posted: 23 October 2023
Starpharma (ASX: SPL, OTCQX: SPHRY) today announces the final positive results from its completed Phase 2 open-label clinical trial of DEP® cabazitaxel. The trial met its objectives, with endpoints demonstrating positive anti-tumour efficacy of DEP® cabazitaxel in advanced, metastatic castrate-resistant prostate cancer (mCRPC), as well as other difficult-to-treat cancers, including platinum-resistant ovarian cancer and gastro-oesophageal cancers. The trial results also confirmed the favourable safety and tolerability profile of DEP® cabazitaxel.
Developed by Starpharma, DEP® cabazitaxel is a patented, dendrimer nanoparticle version of cabazitaxel (Jevtana®), which is widely used in the treatment of prostate cancer, with Jevtana® achieving peak sales of €433 million in 20211.
In Starpharma’s Phase 2 trial, DEP® cabazitaxel achieved highly encouraging anti-tumour efficacy in multiple advanced solid cancers, including metastatic castration-resistant prostate cancer, platinum-resistant ovarian cancer, and gastro-oesophageal cancers.
Summary of key efficacy results:
- Heavily pre-t]reated, advanced prostate cancer patients (mCRPC) treated with DEP® cabazitaxel achieved a median progression-free survival (PFS) that was more than 50% longer and a median overall survival (OS) that was 10% longer than published data for Jevtana® at the same dose2. These final progression-free survival results improve upon the interim results on DEP® cabazitaxel reported by Starpharma at the ESMO (European Society of Medical Oncology) Congress 20223.
- In advanced, platinum-resistant ovarian cancer patients, who were heavily pre-treated with an average of 4 prior lines of chemotherapy, DEP® cabazitaxel achieved a disease control rate (DCR) of 66.7% and an objective response rate (ORR) of 17.6%, which compares favourably to standard-of-care therapies that report ORRs ranging from ~9 to 16%4,5,6.
- In advanced gastro-oesophageal cancer patients, DEP® cabazitaxel achieved a median progression-free survival (PFS) and median overall survival (OS) that were 53.1% and 28.5% longer, respectively, than similar patient cohorts treated with standard-of-care paclitaxel7.
These very encouraging DEP® cabazitaxel efficacy results were also clinically significant, given all patients had late-stage, hard-to-treat cancers, and had failed multiple therapies, including closely related taxanes8, prior to entering this trial.
Furthermore, these positive efficacy results in prostate, ovarian, and gastro-oesophageal cancers demonstrate the significant market value and growth potential for DEP® cabazitaxel, not only in the approved prostate cancer indication of Jevtana®, but also in other cancers that have a high unmet medical need.
Importantly, DEP® cabazitaxel was also very well tolerated across the trial in patients who were often elderly, heavily pre-treated and had advanced disease. The overall rate of grade 3 or 4 non-haematological, treatment-related adverse events (AEs) across all DEP® cabazitaxel treated patients (21.3%) was approximately half that reported for Jevtana® (40%)2 at the same dose. Unlike standard cabazitaxel, DEP® cabazitaxel is highly water soluble and does not contain toxic excipients (detergents) that can cause anaphylaxis, so patients do not need to be pre-medicated with steroids or antihistamines when using DEP® cabazitaxel, leading to an improved patient experience.
Commenting on the positive DEP® cabazitaxel Phase 2 results:
Professor James Spicer, FRCP, MBBS, PhD, Professor of Experimental Cancer Medicine at King’s College London and Consultant in Medical Oncology and the Principal Investigator for the trial at Guy’s Hospital in London, commented:
“In our cancer early phase trials unit at Guy’s Hospital, we conduct many studies of novel oncology therapeutics. The results with DEP® cabazitaxel clearly demonstrate promising and durable anti-cancer activity in very hard-to-treat cancer patients, not only in prostate cancer patients but also platinum-resistant ovarian cancer, and advanced gastro-oesophageal cancers. These advanced patients have few treatment options and we have had many patients who benefited from DEP® cabazitaxel therapy. It was also pleasing to see the limited impact on bone marrow function of this agent given these advanced patients are often at risk of complications of chemotherapy-induced bone marrow toxicity, especially low neutrophil counts.”
Dr David Pinato, MD, MRCP (UK), MRes, PhD, Clinical Reader and Consultant Medical Oncologist, Director of Developmental Cancer Therapeutics, and Investigator for the trial at Imperial College London, said:
“I am impressed with the data on Starpharma’s novel dendrimer formulation of cabazitaxel, not only in prostate cancer patients, but in patients with other difficult-to-treat diseases such as advanced platinum-resistant ovarian and gastro-oesophageal cancers.
“DEP® cabazitaxel showed very encouraging efficacy signals in these heavily pre-treated patients who have few options remaining.
“For example, in elderly patients with prostate cancer who typically would not tolerate standard cabazitaxel due to low neutrophil counts and other adverse effects, treatment with DEP® cabazitaxel was possible due to its lack of significant effects on the bone marrow and its generally well tolerated safety profile, and achieved some excellent outcomes for these patients.
“Based on the data and my experience with DEP® cabazitaxel, it represents a well-tolerated and promising treatment alternative, not only to standard cabazitaxel for prostate cancer patients, but also for ovarian, gastro-oesophageal and potentially other cancers for which standard cabazitaxel is not indicated.”
