Melbourne, Australia; 17 April 2023: Starpharma (ASX: SPL, OTCQX: SPHRY) today announces that it has completed enrolment and treatment of patients for the Phase 2 clinical trial of its investigational anticancer product DEP^® cabazitaxel. Encouraging efficacy signals, including significant tumour shrinkage and substantial tumour biomarker reductions, have been observed in multiple cancer types, including prostate cancer, ovarian cancer, gastro-oesophageal cancer, cholangiocarcinoma and head and neck cancer, following treatment with DEP^® cabazitaxel.

Developed by Starpharma, DEP^® cabazitaxel is a patented, dendrimer nanoparticle version of the chemotherapy drug, cabazitaxel, which is marketed as Jevtana^® and widely used in the treatment of prostate cancer. Unlike standard cabazitaxel, DEP^® cabazitaxel is highly water soluble, does not contain toxic detergent-like excipients associated with anaphylaxis, and avoids the need for patients to pre-medicate with steroids. DEP^® cabazitaxel is one of three clinical-stage anticancer products developed by Starpharma, with a fourth being clinically developed by Starpharma’s partner, AstraZeneca, and others in preclinical development.

In the Phase 2 trial of DEP^® cabazitaxel, a total of 76 patients were enrolled across sites in the United Kingdom and Australia, with the final patient having now completed treatment. In the latter part of the trial, patient enrolment was focused on certain hard-to-treat cancers, including platinum-resistant ovarian and gastro-oesophageal cancers where encouraging efficacy signals have been observed. Given the challenges faced by patients with these tumours and the advanced nature of their disease, multiple patients who were recruited into the trial subsequently failed clinical, laboratory or radiological screening, which impacted recruitment rates in the latter stage of the trial.

Starpharma previously reported preliminary results from the prostate cancer cohort of the Phase 2 trial of DEP^® cabazitaxel and presented these at the European Society of Medical Oncology Congress in September 2022. As previously announced[1], DEP^® cabazitaxel showed multiple potential benefits for patients with metastatic Castration-Resistant Prostate Cancer (mCRPC), including longer progression-free survival (PFS) and a lower incidence of key side effects than conventional cabazitaxel (Jevtana^®). The median PFS for DEP^® cabazitaxel in this cohort was 3.9 months[2], which is more than 30% longer than the 2.9 months[3] reported for standard cabazitaxel. mCRPC patients treated with DEP^® cabazitaxel also experienced a lower incidence of severe (Grade 3 or 4) treatment-related adverse events (7.5%²), compared to published data on standard cabazitaxel (39.7%)³. No mCRPC patients experienced severe hypersensitivity reactions and patients were not required to have steroid pre-medication, in contrast to standard cabazitaxel. In addition, only two mCRPC patients required prophylactic G-CSF[4], which is commonly required in prostate cancer patients treated with Jevtana^®.

Having now completed dosing of patients in the DEP^® cabazitaxel trial, Starpharma and its specialist clinical research organisation are now focused on follow-up and finalising the patient data set and quality control processes. At this stage, Starpharma expects to report top-line results from the Phase 2 clinical trial of DEP^® cabazitaxel during Q3 CY23, following the final requisite data verification and review. In parallel, licensing activities and discussions for DEP^® cabazitaxel are ongoing as part of the Company’s DEP^® commercialisation strategy.

Dr Jackie Fairley, CEO of Starpharma, commented: “We are pleased to have completed enrolment and treatment of patients in Starpharma’s Phase 2 clinical trial of DEP^® cabazitaxel. DEP^® cabazitaxel demonstrated longer progression-free survival in the prostate cancer cohort as well as a lower incidence of key side effects in patients[5] in comparison with published data on standard cabazitaxel treatment. We look forward to reporting data from other patient cohorts.

“We would like to express our gratitude to the patients who participated in this trial, as well as our appreciation for the contributions made by our clinical investigators and the clinical teams. Thank you to all involved for your dedication to developing improved oncology medicines for patients.”

In addition to this DEP^® cabazitaxel trial completing enrolment and treatment of patients, Starpharma’s Phase 2 monotherapy trials of DEP^® docetaxel and DEP^® irinotecan are in the final stages, with commercial discussions for these products also underway.

View the full announcement here.

[1] ASX Announcement, dated 12 September 2022, ‘Starpharma presents promising additional clinical data for DEP^® cabazitaxel in prostate cancer’.

[2] Jones, RH, et al. Efficacy and Safety of Dendrimer-Enhanced (DEP^®) Cabazitaxel (CTX-SPL9111) in Men with Metastatic Castration-Resistant Prostate Cancer (mCRPC) in a Phase 1/2 Trial, ESMO 2022 Congress, FPN 1403P.

[3] Eisenberger, M, et al. J Clin Oncol, 2017;35(28):3198-206.

[4] G-CSF: granulocyte-colony stimulating factor, is used as a therapy for myelosuppression. Myelosuppression is a condition in which bone marrow function is adversely impacted, resulting in fewer red blood cells, white blood cells, and platelets. It is a side effect of some cancer treatments.

[5] ASX Announcement, dated 12 September 2022, ‘Starpharma presents promising additional clinical data for DEP® cabazitaxel in prostate cancer’.