Siranomics begins phase-I trial of siRNA drug candidate STP707 to treat tumours

Sirnaomics has started phase-I clinical trial for evaluation of the safety, tolerability and anti-tumour activity of the company’s siRNA (small interfering RNA) drug candidate, STP707 with intravenous (IV) administration in the US. The first two patients in the clinical trial have received treatment, the company notified via a statement.

The phase-I clinical trial, a multi-centre, open-label, dose-escalation and dose-expansion study, will evaluate the safety, tolerability and anti-tumour activity of STP707. Thirty participants with advanced solid tumours, who have been unresponsive to standard therapies, will be enrolled in dose escalation. Once maximum tolerated dose or recommended phase-II dose has been established, up to 10 additional patients will be enrolled to confirm safety and explore anti-tumour activity. The study encompasses five cohorts who will receive one of five escalating doses of STP707 through IV administration on a 28-day cycle. The primary endpoints are to determine maximum tolerated dose and establish dosage recommendations for future phase-II studies. Additional secondary endpoints are to determine the pharmacokinetics of STP707, and to observe preliminary anti-tumour activity, added the statement.

“The first dosing of STP707 in patients with hepatocellular carcinoma and other types of solid tumours through IV administration is a significant milestone as we seek to advance this novel siRNA therapeutic, which has demonstrated promising activity in our pre-clinical efficacy and safety studies,” said Patrick Lu, PhD, founder, Chairman of the Board, Executive Director, President and CEO, Sirnaomics, in the statement.

He further said, “Our goal is to take advantage of polypeptide nanoparticle (PNP) formulated siRNA therapeutics for unmet clinical needs, specifically in the areas of oncology and fibrotic diseases. The company is inspired to lead the RNAi community in the development of novel oncology therapeutics, and initiating this study helps us work towards achieving that.”

“Sirnaomics’ mission is to leverage research in RNAi therapeutics to develop drug candidates, which includes STP707, that are able to solve critical unmet needs for patients with a variety of cancers,” said Michael Molyneaux, MD, Executive Director and Chief Medical Officer, Sirnaomics.

He also said, “With the start of this phase-I clinical trial, we can expand our therapeutic reach using IV administration as a modality. In doing so, it opens us up to more opportunities to explore the impact of STP707, including the appropriate dosage and anti-tumour activity that we’ve already seen in previous studies.”

STP707 takes advantage of a dual-targetted inhibitory property and a PNP-enhanced targetted delivery to solid tumours and metastatic tumours via intravenous administration. An initial pre-clinical study has demonstrated that simultaneously knocking down TGF-β1 and COX-2 gene expression in the tumour microenvironment increases active T cell infiltration. A further combination study demonstrated synergistic anti-tumor activity between STP707 and a PD-L1 antibody using a mouse orthotopic liver cancer model.