Nektar and Collaborators Present Preclinical Data on NKTR-255, a Novel IL-15 Receptor Agonist, in combination with CAR Cell Therapies at the 2022 Tandem Meetings | Transplantation & Cellular Therapy Meetings of ASTCT™ and CIBMTR®

SAN FRANCISCO, April 23, 2022 /PRNewswire/ -- Nektar Therapeutics (Nasdaq: NKTR) announced that collaborators from the Cairo Laboratory at New York Medical College today presented data from several preclinical studies demonstrating the potential of NKTR-255 to enhance the anti-tumor activities of different CAR-T therapies in a variety of cancer preclinical models. Presentations include an oral presentation by Wen Luo, Ph.D., assistant professor of pediatrics at NYMC, on in vivo and in vitro efficacy of NKTR-255 combined with anti-MCAMa CARb modified Natural Killer (NK) cells in several tumor models, and a poster presentation by Yaya Chu, Ph.D., assistant professor of pediatrics at NYMC, presenting studies of NKTR-255 in combination with ex vivo expanded anti-CD19 CAR NK cells and anti-CD20 or anti-CD79 antibodies in models of Burkitt Lymphoma (BL).

"Our research builds on the body of knowledge for the role of an agent which activates the full IL-15 biology pathway in the field of cell therapy," said Mitchell S. Cairo, M.D., director of the Cairo Laboratory, chief of pediatric hematology, oncology and stem cell transplantation, director of the Children and Adolescent Cancer and Blood Diseases Center, associate chairman of the Department of Pediatrics and professor of pediatrics, medicine, pathology, microbiology and immunology and cell biology and anatomy at NYMC. "My lab's findings show that NKTR-255's ability to expand and proliferate NK cells resulted in the enhancement of the efficacy of two different CAR therapies in our preclinical models."

The oral presentation will be virtually live streamed on Saturday April 23rd, 2022 at 3:00 PM MT and is accessible through the meeting organizer's website at https://www.astct.org/attend/tandem-meetings. These presentations are available for download at http://www.nektar.com/science/scientific-posters.

Key details and takeaways from the two collaborator presentations include:

Abstract 27: "Targeting Ewing sarcoma, Osteosarcoma and Neuroblastoma with Anti-MCAM Chimeric Antigen Receptor Modified Natural Killer Cells" Luo, W., et al.Presentation Type: Oral PresentationPresenting Author: Wen Luo, Ph.D.Session: Oral Abstract - Session C - Immune and Gene TherapyVirtual Live Stream of the presentation will begin at 3:00 PM MT on Saturday April 23rd, 2022

• NKTR-255 enhances expression of NK cell-activating receptors, stimulates NK cell proliferation and sustains NK cell expansion
• NKTR-255 enhances anti-MCAM CAR NK cell cytotoxicity against Ewing sarcoma, osteosarcoma and neuroblastoma in vitro
• Anti-MCAM CAR NK alone or in combination with NKTR-255 significantly decrease lung metastasis and prolong animal survival in an Ewing sarcoma orthotopic mouse model

Abstract 201: "Optimizing Chimeric Antigen Receptor (CAR) Engineered NK Cell- Mediated Cytotoxicity Combined with anti-CD20 or anti-CD79 Therapeutic Antibodies and NKTR-255 in Burkitt Lymphoma (BL)" Chu, Y., et al.Presentation Type: Poster

• NKTR-255 + obinutuzumab, a humanized type II anti-CD20 monoclonal antibody (mAb) glycoengineered to enhance Fc receptor affinity, significantly enhanced the in vitro cytotoxicity of anti-CD19 CAR NK compared to controls against multiple Burkitt lymphoma model (Raji) (p