NKGen Biotech Updates Phase 1 Data on SNK02 NK Cell Therapy for Solid Tumors at 2024 Summit

On June 12, 2024, NKGen Biotech, Inc. (Nasdaq: NKGN), a clinical-stage biotechnology firm, gave a presentation led by Paul Y. Song, MD, the company's Chairman and CEO. The presentation elaborated on the innovative commercial manufacturing and cryopreservation process of their novel allogeneic blood-derived NK cell therapy, labeled "SNK02." Dr. Song's talk, titled "Protecting Patients by Removing the Need for Lymphodepletion to Better Preserve Immune Function," underscored the potential advantages of skipping pre-treatment lymphodepletion for patients undergoing SNK02 therapy. This approach aims to protect immune function and possibly enhance treatment efficacy by reducing toxicity.

The presentation shed light on early Phase 1 results from treating advanced refractory solid tumors with SNK02. Dr. Song discussed findings that were previously revealed at the 2024 American Society for Clinical Oncology annual meeting, along with some unpublished Phase 1 data. The trial involved administering SNK02 intravenously once a week over an eight-week period, beginning with a dose of 6 x 10^9 SNK02 cells, all without lymphodepletion. Key evaluation metrics included safety, tolerability, and the maximum tolerated dose, alongside clinical activity against heavily pre-treated solid tumors.

Dr. Song emphasized that while most NK cell therapies focus on liquid tumors and often involve lymphodepletion, this could be harmful for patients with solid tumors. This is particularly significant for those receiving immune checkpoint inhibitors, monoclonal antibodies, or bispecific therapies, where a strong immune response is crucial. NKGen’s objective was to develop a scalable process capable of generating over 100,000 doses of cryopreserved enhanced NK cells, potentially enabling large doses without the need for lymphodepletion to overcome host-versus-graft reactions.

Initial Phase 1 results showed that SNK02 was well-tolerated as a monotherapy and demonstrated some clinical activity against solid tumors. Among the six patients enrolled, who had a median age of 64 and an average of four prior therapies, the cancer subtypes included colorectal cancer, leiomyosarcoma, angiosarcoma, endometrial adenocarcinoma, and undifferentiated pleomorphic sarcoma. Four of these patients completed eight cycles of SNK02, and all showed stable disease, meaning their tumors did not grow further. One patient even received 18 weekly doses, while another received 12.

During the trial, out of 36 doses administered through the eighth cycle, there were 21 adverse events (AEs) related to the investigational product, including 17 Grade 1, three Grade 2, and one Grade 3 event. The Grade 3 event of increased fatigue resolved within a day without any intervention. One death occurred during the study but was deemed unrelated to the investigational product. The development of autoantibodies was noted around the fifth cycle, correlating with some AEs. However, there was no apparent correlation between KIR mismatch or HLA subtyping with AEs or tumor response.

The promising results from this Phase 1 trial indicate that SNK02 is a viable monotherapy option and could be even more effective in combination with immune checkpoint inhibitors and antibodies targeting solid tumors. SNK02 is a cutting-edge cell-based immunotherapeutic drug candidate derived from donors and expanded ex vivo. NKGen aims to utilize SNK02 to treat a broad spectrum of cancers, continuing its mission as a clinical-stage biotech company dedicated to innovative NK cell therapeutics. NKGen is based in Santa Ana, California, USA.