Sirnaomics announces interim data from phase-II clinical trial of STP705 to treat cutaneous BCC

Sirnaomics recently announced interim data from a phase-II clinical trial of STP705, a siRNA (small interfering RNA) therapeutic, for the treatment of cutaneous Basal Cell Carcinoma (BCC). The interim data, which examines results from three cohorts with 15 total subjects, shows a dose response with complete response, as well as an improved or stable cosmetic result with no significant cutaneous skin reactions. Interim data also suggests a favourable safety profile as there are no drug-related adverse events or serious adverse events, according to a statement from Sirnaomics.

The statement also said that the phase-II open-label, dose-escalation study is designed to evaluate the safety, tolerability and efficacy of various doses of STP705 administered as localised injection in patients with BCC. The primary endpoint is to determine the proportion of participants with a complete response of treated BCC at the end of treatment, which is defined as the absence of detectable evidence of BCC tumour cell nests. The secondary endpoints are to determine the safe and effective recommended dose of STP705, and an analysis of biomarkers common to BCC formation pathway, including TGF-β1 and COX-2.

The interim analysis comprises three dose escalation cohorts ranging from 30μg to 90μg with five patients in each group, for a total of 15 patients enrolled in the trial so far. Participants received injections of STP705 once a week for up to six weeks. In cohorts B and C, which received doses of STP705 at 60µg and 90µg respectively, three out of five patients achieved a complete response. Cohort A, which received a 30µg dose, saw a complete response in one out of five participants, the statement further said.

“This interim data indicates that STP705 achieved therapeutic responses from patients with BCC, in addition to the positive readouts from patients with SCC, which further demonstrates our leadership in developing RNAi-based treatments for skin cancers,” said Patrick Lu, PhD, the founder, Chairman of the Board, Executive Director, President and CEO, Sirnaomics, in the statement.

Lu added, “We look forward to seeing the results of our next data readout in this phase-II study with the rest of participant cohorts, which will give us more insights into the efficacy of STP705 as we seek to move this important therapeutic candidate forward.”

“These encouraging interim results from the phase-II clinical trial of STP705 suggest that we are on a path to potentially offer a treatment for patients with BCC that would be an alternative to surgical excision of these lesions,” Michael Molyneaux, MD, Executive Director and Chief Medical Officer, Sirnaomics, also said in the statement.

“There is an unmet need for non-surgical treatments for various types of non-melanoma skin cancers that reduce scarring and achieve high rates of complete response, which we have begun to see in this arm of the study,” Molyneaux added.

The remaining portion of the phase-II study will include two additional cohorts of five subjects with dosing of 120μg and 180ug, for a total of 25 participants in the clinical trial, the statement concluded.