First-in-human trial shows no dose-limiting toxicities in six subjects treated as out-patients with PD-L1.t-haNK off-the-shelf CAR NK cell therapy with potential to overcome limitations of CAR-T therapies for solid tumors

 CULVER CITY, Calif., Dec. 2, 2019 – NantKwest, Inc. (Nasdaq: NK), a clinical-stage natural killer cell-based therapeutics company today announced promising safety data generated from the first six patients in its QUILT-3.064 trial. The first-in-human study evaluated the safety and preliminary efficacy of the Company’s first-in-class, tumor-targeted PD-L1.t-haNK cell therapy in patients with locally advanced or metastatic solid tumors.

“The unique dual-targeting of PD-L1.t-haNK to both PD-L1 expressing tumors and therapeutic monoclonal antibodies has the potential to be transformative to the treatment of advanced solid tumors with cell-based therapies,” said Dr. Patrick Soon-Shiong, the Chairman and CEO of NantKwest. “PD-L1.t-haNK is a cryopreserved, off-the-shelf product that can rapidly deliver treatment to patients in an outpatient setting while avoiding the extensive manufacturing delays associated with autologous CAR-T therapies. We look forward to reporting full study results from the phase 1 cohort and moving toward a recommended phase 2 dose. We continue to advance our innovative cell therapies such as PD-L1.t-haNK in combination with ImmunityBio’s N-803, an IL-15 superagonist that is designed to stimulate the activation and proliferation of the patient’s own NK cells to maximize the potential of immunogenic cell death to treat cancer,” continued Soon-Shiong.  NantKwest and a wholly owned subsidiary of ImmunityBio have entered into an exclusive collaboration agreement to co-develop NantKwest’s proprietary off-the-shelf NK platforms in combination with N-803.

On December 2, 2019 at the NantKwest Key Opinion Leader and Investors conference, Dr. Soon-Shiong described the clinical development plans for two of NantKwest’s first-in-class NK products: haNK, which was developed to target binding to approved monoclonal therapies such as Trastuzumab, Rituximab and Cetuximab; and PD-L1.t-haNK, which was also designed to target these approved therapies plus directly target PD-L1-expressing tumor cells.

PD-L1.t-haNK cells are a human-derived, allogeneic, natural killer cell line engineered to express a chimeric antigen receptor (CAR) targeting PD-L1, whose origins arise from NantKwest’s proprietary NK-92 (aNK) master cell bank.  In addition to targeting PD-L1, PD-L1.t-haNK is engineered to produce intracellular IL-2 for enhanced CD16-targeted antibody-dependent cellular cytotoxicity capabilities.

John Lee, M.D., Clinical Senior Vice President at NantKwest said, “We are highly encouraged by the early safety results with PD-L1.t-haNK in a patient population with advanced, difficult to treat solid tumors. All patients were able to be infused in the outpatient setting without any reported cytokine toxicities or immune related adverse events.  NantKwest’s approach has been designed to overcome the challenges and limitations typically seen when treating solid tumors with CAR-T and other immunotherapy approaches and I look forward to progressing our studies to advance this innovative new approach to cancer therapy.”

Study Design

The QUILT-3.064 study is an open-label, Phase 1 study of PD-L1.t-haNK in subjects with locally advanced or metastatic solid cancers to evaluate safety, preliminary efficacy, determine maximum tolerated dose (MTD) or highest tolerated dose (HTD) and designate the recommended Phase 2 dose (RP2D). The study is being conducted in two parts: the first is evaluating dose escalation using a 3 + 3 design and the second part will evaluate the expansion of the recommended Phase 2 dose (RP2D) to further assess the safety and efficacy of PD-L1.t-haNK therapy. In part one, six subjects were sequentially enrolled, starting at dose level 1 and assessed for dose-limiting toxicities. The primary study objectives are to determine the MTD or HTD, RP2D (recommended phase 2 dose), and safety. The secondary endpoints include objective response rate (ORR), progression free survival (PFS) and overall survival (OS). More information can be found at ClinicalTrials.gov, Identifier: NCT04050709.

About NantKwest

NantKwest (NASDAQ: NK) is an innovative, clinical-stage immunotherapy company focused on harnessing the power of the innate immune system to treat cancer and virally induced infectious diseases. We are the leading producer of clinical dose forms of off-the-shelf Natural Killer (NK) cell therapies. Our activated NK cell platform is designed to destroy cancer and virally infected cells from the body. The safety of our optimized, activated NK cells, as well as their activity against a broad range of cancers, have been tested in phase I clinical trials in Canada and Europe, as well as in multiple phase I and II clinical trials in the United States. By leveraging an integrated and extensive genomics and transcriptomics discovery and development engine, together with a pipeline of multiple, clinical-stage, immuno-oncology programs, NantKwest’s goal is to transform medicine by delivering living drugs in a bag and bringing novel NK cell-based therapies to routine clinical care. NantKwest is a member of the NantWorks ecosystem of companies. For more information, please visit https://nantkwest.com.

haNK is a registered trademark of NantKwest, Inc.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements concerning or implying that NantKwest will be successful in improving the treatment of cancer. Risks and uncertainties related to this endeavor include, but are not limited to, obtaining FDA approval of NantKwest’s NK cells as well as other therapeutics as part of the NANT Cancer Vaccine platform as a cancer treatment.

Forward-looking statements are based on management’s current expectations and are subject to various risks and uncertainties that could cause actual results to differ materially and adversely from those expressed or implied by such forward-looking statements. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements.

These and other risks regarding NantKwest’s business are described in detail in its Securities and Exchange Commission filings, including in NantKwest’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2019. These forward-looking statements speak only as of the date hereof, and we disclaim any obligation to update these statements except as may be required by law.