NantKwest Announces Presentation of Positive Phase 2 Clinical Data of Natural Killer Cell Therapy in Metastatic Merkel Cell Carcinoma at SITC 2019

NantKwest Inc. (Nasdaq: NK), a next generation, clinical-stage immunotherapy company focused on harnessing the unique power of our immune system using natural killer (NK) cells to treat cancer, infectious diseases and other diseases, today announced the presentation of results from their Phase 2 trial investigation using aNK, NantKwest’s off-the-shelf natural killer cell-based therapeutic, in combination with N-803, ImmunityBio’s IL-15 superagonist, in patients with advanced refractory metastatic Merkel cell carcinoma (MCC) (NCT03853317) at The 34^th Annual Meeting of the Society for Immunotherapy for Cancer (SITC 2019) on November 8, 2019 in National Harbor, Maryland. ImmunityBio is an affiliate company of NantKwest.

Dr. Shailender Bhatia, Associate Professor of Medical Oncology at the University of Washington/Fred Hutchinson Cancer Research Center, will make an oral presentation entitled “Final results from a phase 2 study using off-the-shelf activated natural killer (aNK) cells in combination with N-803, an IL-15 superagonist, in patients with metastatic Merkel cell carcinoma (MCC).” That study demonstrated long term, durable responses in 2 of 7 patients with advanced refractory MCC. One of these patients achieved a radiologic complete response, and the second a durable partial response with more than 75% tumor regression and no subsequent therapy (response ongoing to date). Both patients with responses in the trial remain alive to date, 29 and 44 months after the initiation of treatment.

Results from this study provide evidence that treatment with aNK cell therapy can stimulate immune responses to checkpoint inhibitors, even in patients that have previously failed treatments using these types of therapies. One heavily pretreated subject refractory to pembrolizumab was rechallenged with this checkpoint inhibitor subsequent to receiving aNK cell therapy resulting in a durable complete response (CR) that is ongoing at this time, 44 months after receipt of first aNK cell infusion.

“We believe the results of this Phase 2 study are testament to the potential of our natural killer cell-based therapeutics to change the cancer treatment paradigm,” said Dr. Patrick Soon-Shiong, Chairman and CEO of NantKwest. “Long term responses in patients with refractory metastatic disease is a remarkable achievement and is supportive of our upcoming trial, which will evaluate NantKwest’s off-the-shelf CD16-targeted haNK cells in combination with N-803 and Pfizer’s avelumab in patients with advanced MCC who are refractory to immune checkpoint inhibitors. We are particularly enthusiastic about the potential of aNK and N-803 to induce sensitization to checkpoint inhibitors, and thus, are evaluating this in our upcoming trial. We remain deeply committed to harnessing the power of immunogenic cell death across a wide range of indications to provide innovative treatments to patients with serious unmet need.”