Sino-US siRNA therapy developer Sirnaomics Ltd (HKG: 2257) has announced the interim results of part one of a Phase IIb clinical study for STP705, a therapeutic that combines TGF-β1/COX-2 with histidine-lysine polypeptide (siRNA/HKP) nanoparticle silencing. The trial is assessing the therapy as a treatment for cutaneous squamous cell carcinoma in situ (isSCC).
Study Design and Interim Results
The two-part, double-blind, randomized, placebo-controlled Phase IIb study is designed to evaluate the safety and efficacy of various doses of STP705, administered as an intralesional injection in subjects with isSCC. In part one of the study, 32 patients were treated with 30 µg/ml, 60 µg/ml, and 90 µg/ml of STP705, respectively, and 12 patients with 0 µg/ml placebo weekly. The interim results showed that, after six weeks of repeated dosing, the majority (78%) of 32 patients with STP705 treatment achieved histological clearance. One of the three treatment cohorts achieved 89% histological clearance. No treatment-related adverse events or serious adverse events occurred, and the local skin reaction values in all treatment groups were stable or improved.
Part Two of the Study
Part two of this study will include 60 additional subjects who will be randomly allocated to receive STP705 or placebo injection once a week for a total of six weeks. In the seventh week, the lesion will be excised.
STP705: Mechanism and Regulatory Approvals
STP705 is a siRNA (small interfering RNA) therapeutic that takes advantage of a dual-targeted inhibitory property and polypeptide nanoparticle (PNP)-enhanced delivery to directly knock down both TGF-β1 and COX-2 gene expression. The product candidate has received multiple IND approvals from both the US FDA and the Chinese National Medical Products Administration (NMPA), alongside orphan drug designations (ODDs) for use in cholangiocarcinoma and primary sclerosing cholangitis. Multiple clinical studies are underway, including a Phase IIb study in isSCC, Phase II study in basal cell carcinoma (BCC), Phase I/II study in keloids, Phase I/II study in hypertrophic scarring, Phase I/II study in facial isSCC, Phase I study in liver cancer, and a Phase I study as a medical aesthetic product.-Fineline Info & Tech
