Replay Appoints Arun Balakumaran M.D., Ph.D as Chief Medical Officer

  • Arun Balakumaran M.D., Ph.D, appointed Chief Medical Officer of Replay to support the Company’s genomic medicine and engineered NK cell therapy pipeline
  • Former Chief Medical Officer of allogeneic CAR-T cell company Allogene Therapeutics and seasoned industry immuno-oncology, and cell and gene therapy expert
  • Dr. Balakumaran also appointed CMO of Syena, Replay’s engineered NK cell therapy product company pioneering first-in-class engineered T-cell Receptor Natural Killer cell (TCR-NK) therapy

San Diego, California and London, UK, May 18, 2023 – Replay, a genome writing company reprogramming biology by writing and delivering big DNA, today announced the appointment of Arun Balakumaran, M.D., Ph.D., as Chief Medical Officer (CMO), effective 22 May.

An expert in immuno-oncology and cell and gene therapy, Dr. Balakumaran brings more than 15 years of clinical development experience at leading biotechnology and pharmaceutical companies, including Merck and Amgen, to the Company. At Replay, Dr. Balakumaran will support the clinical development of Replay’s differentiated portfolio of next-generation genomic medicines and technology platforms, including its first-in-class engineered TCR-NK cell therapy programs that are anticipated to enter the clinic later this year.

Dr. Balakumaran joins Replay from Allogene Therapeutics (NASDAQ: ALLO), where he served as CMO and Senior Vice president, overseeing the Company’s clinical development strategy across multiple allogeneic cell therapy programs. Prior to that, he held roles of increasing seniority at Merck (NASDAQ: MRK), where he was the Product Development Lead for Hematological Malignancies and led the activities resulting in breakthrough designations and the eventual approval of Pembrolizumab® in lymphoma. Prior to that he was Clinical Research Medical Director at Amgen (NASDAQ: AMGN), and Medical Lead in Oncology.

Dr. Balakumaran began his career at the National Institutes of Health (NIH), where he was Medical Lead for the Bone Marrow Stromal Cells (MSC) Transplant Center. He is a board-certified hematologist and medical oncologist and holds a Master’s degree in healthcare management from Harvard University. Dr. Balakumaran also serves on the Board of Onco Filtration Inc. and the Scientific Advisory Board of SDS Optic.

Dr. Balakumaran will, additionally, join Replay’s engineered TCR-NK cell therapy product company Syena as CMO, where he will support the clinical development of its first-in-class and first-in-human engineered TCR-NK cell therapy clinical programs in both hematological malignancies and solid tumors. Syena was co-founded by Professor Katy Rezvani, M.D., Ph.D., and is developing a scalable, off-the-shelf, cord blood-derived engineered TCR-NK platform, which was licensed exclusively from The University of Texas MD Anderson Cancer Center, in February 2023.

Adrian Woolfson, Executive Chairman, President, and Co-Founder of Replay, commented: “Arun’s extensive expertise across cell and gene therapy, and immuno-oncology, will be invaluable for Replay and its product companies, including our first-in-class engineered TCR-NK cell therapy company, Syena. He will be joining a rapidly expanding team of world-class industry experts, academics, and entrepreneurs at Replay, where we are focused on delivering new therapeutic options for some of the key global medical challenges addressable using genomic medicine and engineered cell therapies. We are delighted to welcome him into our team.”

Lachlan MacKinnon, CEO and Co-Founder of Replay, added, “We have watched Arun’s progress at Allogene Therapeutics where he has been instrumental in advancing their allogeneic cell therapy programs into the clinic. His knowledge and experience will be of critical importance to the Company as we progress our genomic medicine pipeline, including the first-in-class TCR-NKs that we are developing within our engineered TCR-NK cell therapy product company, Syena.”

“Replay has the potential to transform the future of genomic medicine through its suite of genomic medicine platform technologies, engineered cell therapies, and innovative approach to corporate structure and product development,” said Dr. Arun Balakumaran, Chief Medical Officer of Replay. “The engineered TCR-NK platform that is being developed in Syena in particular, provides the promise of a highly scalable and off-the-shelf cell therapy with the potential to evade the primary mechanism of acquired resistance in existing cell therapies, through their innate anti-tumor activity. I look forward to working with the Replay executive team, Katy Rezvani at MD Anderson, and the Syena team to progress engineered TCR-NKs and the Company’s other programs and technologies including HSV-based gene therapy, into the clinic for the benefit of patients with high unmet medical needs.”


About Replay

Replay is a genome writing company, which aims to define the future of genomic medicine through reprogramming biology by writing and delivering big DNA. The Company has assembled a toolkit of disruptive platform technologies – including a high payload capacity HSV platform, a hypoimmunogenic cell therapy platform, and a genome writing platform – to address the scientific challenges currently limiting clinical progress and preventing genomic medicine from realizing its full potential. The Company’s hub-and-spoke business model separates technology development within Replay from therapeutic development in product companies that leverage its technology platforms. For example, the Company recently incorporated a first-in-class engineered TCR-NK cell therapy product company developed by Professor Katy Rezvani at the MD Anderson Cancer Center. Replay’s synHSV™ technology, a high payload capacity HSV vector capable of delivering up to 30 times the payload of AAV, is utilized by Replay’s four gene therapy product companies, bringing big DNA treatments to diseases affecting the skin, eye, brain, and muscle. Replay is led by a world-class team of academics, entrepreneurs, and industry experts.

The Company raised $55 million in seed financing in July 2022 and is supported by an international syndicate of investors including: KKR, OMX Ventures, ARTIS Ventures, and Lansdowne Partners. Replay is headquartered in San Diego, California, and London, UK. For further information please visit and follow us on LinkedIn and Twitter.



Dr Adrian Woolfson / Lachlan MacKinnon

Consilium Strategic Communications – Media relations

Amber Fennell / David Daley / Melissa Gardiner

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