Saint-northern medicine-B (02257) announced that the group has completed Phase I clinical trials of STP707, which has a strong safety profile and stable disease activity in treating pancreatic cancer patients. It is a dose-escalation study conducted in 11 oncology clinics in the USA. The study involved six groups, including 50 patients with various cancers, 11 of whom had pancreatic cancer.
In a press release previously issued by the company in August 2023, the group stated that the Phase I study of its STP707 for the treatment of multiple solid tumors had completed all dosing regimens. It was a basket study that recruited patients with various advanced cancers that had failed multiple rounds of therapy. Through six escalating dose levels of intravenous injection, the study aimed to evaluate the safety, tolerability, and antitumor activity of the group's siRNA (small interfering RNA) candidate drug STP707. The study recruited patients with late-stage/metastatic or unresectable solid tumors who were unresponsive to standard therapy, including pancreatic cancer, colorectal cancer, liver cancer, melanoma, and other cancer patients. We explored six dose levels (3mg/kg, 6mg/kg, 12mg/kg, 24mg/kg, 36mg/kg, and 48mg/kg) in the dose-escalation stage. Patients received intravenous infusion on days 1, 8, 15, and 22 of a 28-day cycle.
The study recruited 11 pancreatic cancer patients (5 male and 6 female, average age 64 years). Before participating in the study, the patients had received extensive treatment, with an average of three treatments (including gemcitabine, paclitaxel, and Folfirinox) before being included in the study. Preliminary results showed that the average treatment duration completed was three cycles (average of 12 doses). The average number of days that all 11 patients had stable disease was 92 days, with 31 days for the 12mg/kg group, 65 days for the 24mg/kg group, and 112 days for the 48mg/kg group. One patient had stable disease for 281 days. None of the 11 patients reported treatment-related adverse events (TRAEs), except for one patient who had grade 2 infusion reaction. Non-treatment-related adverse events secondary to their late-stage metastatic disease included intestinal obstruction, abdominal distension, gastrointestinal obstruction, embolism, gastrointestinal bleeding, tumor pain, hypoxia, and respiratory distress.
Even at the 48mg/kg dose level, none of the 50 advanced cancer patients reached the maximum tolerated dose of STP707. STP707 showed excellent tolerability in a population of cancer patients who had received extensive treatment. 11 pancreatic cancer patients exhibited low toxicity and relatively stable disease at different doses (106, 281, and 302 days), and given STP707's demonstrated ability to recruit T cells to the tumor microenvironment (TME) in preclinical studies, we believe that it is necessary to use STP707 alone or in combination with immunotherapy for further research. This is the first time that a siRNA cancer therapeutic based on peptide nanoparticles has demonstrated early positive safety and efficacy results in the treatment of advanced pancreatic cancer patients.
"We are delighted to see STP707, our leading siRNA drug product, for the treatment of pancreatic cancer – one of the deadliest types of tumors, show such strong results after intravenous administration. This is a very promising result for RNAi-based cancer therapies to treat metastatic tumors," said Dr. Patrick Lu, founder, chairman of the board, executive director, president, and chief executive officer of Sirnaomics. "This IV-administered STP707 preparation has demonstrated powerful safety, sustained disease efficacy, and dose-dependent anticancer activity in a population of cancer patients who have received extensive treatment, either as a standalone drug or in combination with immunotherapy drugs, it is a potential new type of cancer therapy approach."