SNB-101 Receives Orphan Drug Designation in Pancreatic Cancer

SNB-101, a novel polymer nanoparticle agent, has been granted orphan drug designation by the FDA for the treatment of patients with pancreatic cancer. The agent is the first nanoparticle anticancer drug that has been developed with extremely insoluble SN-38 incorporated into polymer nanoparticles.¹

At a data cutoff of April 28, 2023, preliminary findings from a phase 1 study (NCT04640480) of SNB-101 in patients with advanced solid tumors, which were presented in a poster during the 2023 ESMO Congress, showed that patients who received the agent (n = 21) achieved an objective response rate (ORR) of 14.29%; all responses were partial.2 Additionally, the disease control rate (DCR) was 42.86%, and the median progression-free survival (PFS) and overall survival (OS) were 1.97 months and 6.83 months, respectively.²

“SNB-101 showed excellent efficacy compared with existing first-line treatments paclitaxel [Abraxane] and irinotecan [Onivyde] in pancreatic cancer animal models,” SN Bioscience, the developer of SNB-101, stated in a press release.¹ “Based on this, [SNB-101] has been designated as an orphan drug by the United States [US] FDA after application in November [2023]. Pancreatic cancer is a typically incurable tumor with an extremely low 5-year survival rate, and cytotoxic anticancer drugs, such as paclitaxel and irinotecan, are currently used as first-line treatments. This is an area of high medical unmet need with limited second-line treatment options.”

The open-label, dose-escalation study enrolled adult patients with histologically/cytologically confirmed, locally advanced/metastatic tumors who experienced progression following standard systemic therapy and were not suitable for complete surgical resection.2 Eligible patients also needed to have measurable disease per RECIST v1.1 criteria and an ECOG performance status of 1 or 0.²

Once enrolled, patients were treated with intravenous SNB-101 at a dose range of 5/8 mg/m² to 50/80 mg/m² of SN-38/irinotecan HCl on days 1 and 15 of each 28-day cycle. Dose escalation, de-escalation, and modification, as well as maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), were determined by an independent safety review committee.

The primary end point was safety, including dose-limiting toxicities (DLTs) and determining the MTD and RP2D of SNB-101. Secondary end points included ORR, PFS, OS, DCR, and pharmacokinetics.

The treated population included patients with colorectal cancer (n = 7), gastric cancer (n = 5), small cell lung cancer (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). The mean age in the overall population was 58 years (range, 42-71), patients had received 2 to 10 prior lines of treatment, and 9 patients had received prior irinotecan.

In terms of safety, the most common any-grade treatment-related adverse effects (AEs) included neutropenia (61.9%), decreased white blood cell counts (28.6%), nausea (23.8%), anemia (23.8%), and decreased platelet counts (19.0%). Common grade 3 or 4 AEs included neutropenia (33.3%), decreased white blood cell counts (14.3%), and decreased platelet counts (9.5%). The MTD was not reached after dose escalation at all planned doses, and 1 patient treated at the 40/64 mg/m² dose level of SN-38/irinotecan experienced a DLT of febrile neutropenia.

Study authors concluded that SNB-101 was well tolerated and neutropenia was manageable, although hematological AEs occurred at relatively high rates. Additionally, they noted that the agent displayed antitumor activity, which appeared to be dose dependent.

SNB-101 received orphan drug designation from the FDA for the treatment of patients with NSCLC in July 2023.¹ SN Bioscience expects to gain momentum in SNB-101 indication expansion and clinical development due to the agent’s orphan drug designation in pancreatic cancer. Additionally, SNB-101 was granted phase 2 approval in Korea in November 2023, and SN Bioscience is preparing for a phase 2 study of the agent in the US and Europe in the second half of 2024.¹

References

1. SN BioScience received US FDA orphan drug designation for its nano anti-cancer drug ‘SNB-101’ on pancreatic cancer. News release. SN Bioscience Co. Ltd. February 29, 2024. Accessed February 29, 2024. https://www.prnewswire.com/news-releases/sn-bioscience-received-us-fda-orphan-drug-designation-for-its-nano-anti-cancer-drug-snb-101-on-pancreatic-cancer-302075576.html
2. Sang YB, Kim Y, Lee MA, et al. Preliminary findings from a phase I, open-label, dose-finding study of SNB-101 in patients with advanced solid tumors. Ann Oncol. 2023;34(suppl 2):S474. doi:10.1016/j.annonc.2023.09.1863