SNB-101 Receives FDA Fast Track Designation for SCLC
The FDA has granted fast track designation to SNB-101 (SN-38), a novel polymer nanoparticle agent, as a potential treatment for patients with small cell lung cancer (SCLC).
SNB-101 is the first nanoparticle anticancer drug to be developed, according to the agent’s developer, SN Bioscience. It is composed of extremely insoluble SN-38—an active metabolite of irinotecan—incorporated into polymer nanoparticles. Preclinical and early-phase results have demonstrated the agent’s improved tolerability and reduced gastrointestinal adverse effects (AEs] compared with current anticancer agents in SCLC. Moreover, SNB-101 has shown efficacy in patients related to lung cancer through lung targeting.
Preliminary results from a phase 1 study (NCT04640480) of SNB-101 in advanced solid tumors were presented in a poster at the 2023 ESMO Congress. At a data cutoff of April 28, 2023, patients who received the agent (n = 21) achieved an objective response rate (ORR) of 14.29%, all of which were partial responses. The agent also elicited a disease control rate (DCR) of 42.86%, a median progression-free survival (PFS) of 1.97 months, and a median overall survival (OS) of 6.83 months.
Patients 18 years of age or older with histologically or cytologically confirmed, locally advanced or metastatic solid tumors that had progressed following standard systemic therapy and were not candidates for complete surgical resection were enrolled onto the open-label, dose-escalation study. Other key eligibility criteria included measurable disease according to RECIST 1.1 criteria and an ECOG performance status of 0 or 1.
Once enrolled, patients received intravenous SNB-101 at doses ranging from 5/8 mg/m2 to 50/80 mg/m2 of SNB-101 on days 1 and 15 of each 28-day cycle until progressive disease, unacceptable toxicity, or death. An independent safety review committee oversaw dose escalation, de-escalation, and modification, as well as the determination of the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D).
The study’s primary end points included safety, dose-limiting toxicities (DLTs), and determination of the MTD and RP2D. Secondary end points comprised ORR, PFS, OS, DCR, and pharmacokinetics.
The treated population comprised patients with colorectal cancer (n = 7), gastric cancer (n = 5), SCLC (n = 3), non–small cell lung cancer (NSCLC; n = 2), head and neck cancer (n = 2), esophageal cancer (n = 1), and soft-tissue sarcoma (n = 1). In the overall population, the mean age was 58 years (range, 42-71), and patients had previously been exposed to 2 to 10 prior lines of treatment. Notably, 9 patients had prior exposure to irinotecan.
Regarding safety, the agent demonstrated a manageable toxicity profile when administered at doses between 5 mg/m2 and 50 mg/m2. Notably, the MTD was not reached following dose escalation at all planned doses. A DLT of febrile neutropenia was observed in 1 patient treated with 40/64 mg/m2 of SNB-101. The most common any-grade treatment-related AEs were neutropenia (61.9%), decreased white blood cell counts (28.6%), nausea (23.8%), anemia (23.8%), and decreased platelet counts (19.0%).
SNB-101 previously received orphan drug designation from the FDA as a potential treatment for patients with NSCLC in July 2023, followed by pancreatic cancer in February 2024.
Global clinical trials of the agent are scheduled to begin in the event of the agent’s phase 2 approval in the United States and Europe in the second half of 2024. Following the agent’s designations in SCLC and pancreatic cancer, SN Bioscience also plans to expand the agent’s indications to other solid tumor types, such as colon cancer, gastric cancer, and biliary tract cancer through additional phase 2 clinical trials.
May 13, 2024
