Vaxil Scientists

Dr. Ari S. Kellen MD Vaxil

Dr. Ari S. Kellen, M.D. – Director

Medical Doctor, University of Witwatersrand | MBA, University of Witwatersrand

Dr. Ari Kellen is a seasoned senior executive with over three decades of healthcare industry experience, both in management consulting and in major global P&L operational roles. Dr. Kellen trained and worked as a physician in South Africa while also running a large segment of a 1,000 bed teaching hospital. After being recruited by McKinsey & Company, he spent 23 years serving healthcare clients around the world. Dr. Kellen served for more than a decade as a Senior Partner at McKinsey, advising CEOs and Board members at large industry-leading healthcare companies and small rapidly growing entities. His experience spans biotechnology, medical device, payor and provider organizations, and includes work focused on M&A, business development, new company spin-outs, corporate and business unit level turnarounds, R&D portfolio strategy, and product / therapeutic area growth strategies. In 2014, Dr. Kellen was recruited to Bausch + Lomb / Valeant where he ran a multi-billion dollar P&L across the US and Latin America. As EVP and General Manager of US Bausch + Lomb, he successfully launched and commercialized new products in Pharmaceuticals, Surgical, and Vision Care / Contact Lenses. Dr. Kellen was also responsible for leading the United States R&D organization to advance more than 100 active R&D projects across Dermatology, Ophthalmology, Gastroenterology, Oncology and Consumer Products. Dr. Kellen currently serves on the Advisory Boards of Paragon Biosciences and Castle Creek Pharmaceuticals.


Dr. Riva Kovjazin, M.D. – Senior Scientist

M.D., Perm State School of Medicine | Immunology Research Fellow, Rostov Research Institute | Research Fellow, Center for Clinical Immunology, Moscow School of Medicine
Dr. Riva Kovjazin is an expert in the field of immunology with over 25 years of experience in cellular immunology. She obtained her M.D. from the Perm State University School of Medicine, one of the oldest universities in Russia. Dr. Kovjazin then specialized in the advanced study of immunology and epidemiology of conventional infectious diseases at the Rostov Research Institute. In addition, she was a project leader at the Center for clinical immunology, University of Medicine, Moscow, Russia where she studied Clinical immunology and diagnosis aspects of HIV. From 1997 until 2007, Dr. Kovjazin held various positions at XTL Biopharmaceutical



Dr. Shawn Langer MD Vaxil

Dr. Shawn Langer, M.D.

Dr. Shawn Langer brings over two decades of healthcare industry experience. Dr. Langer was Senior Partner at McKinsey & Company, where he was the leader of its Healthcare Private Equity Group.

During his 15 years with McKinsey & Company, Dr. Langer served healthcare clients across pharmaceuticals, biotechnology, medical devices, and healthcare services.

Most recently Dr. Langer has spent nearly 5 years investing in innovative healthcare companies in his capacity as a portfolio manager at healthcare private equity investment firm BMHS Investments.



Dr. Terry Plasse, M.D. – Clinical Affairs

MD, Washington University School of Medicine, St. Louis | Medical Oncology, Beth Israel Hospital and Mt. Sinai Hospital, NYC | BSc, Chemistry, Brandeis | Former Lieutenant Commander (Full Surgeon) US National Health Service Corps.

Dr. Terry Plasse began his career as a New York oncologist before entering the biotech world, most recently in Israel. Dr. Plasse was previously North American Director, Oncology Clinical Research, for multi-national Rhone-Poulenc Rorer, which merged with Sanofi, now the world’s 5th largest pharma company. There, Dr. Plasse oversaw North American R&D focused on clinical trials for its cancer products, including docetaxel which is marketed worldwide by Sanofi with sales in the billions.

Additionally, Dr. Plasse oversaw a clinical trial for Astra Zeneca’s gefitnib, a drug which has been approved for lung cancer. He consulted Merck in relation to vorinostat (Zolinza), approved by FDA for treatment of cancer. Dr. Plasse conducted early analyses for Bristol Myers Squibb for its renowned checkpoint inhibitor ipilimumab, the first approved cancer immune checkpoint inhibitor.

Dr. Plasse also brings experience leading small biotech companies, with leadership positions at Interferon Sciences, UniMed, and Cytokine PharmaSciences. Most recently, Dr. Plasse became Medical Director for Redhill BioPharma, an Israeli biotech which successfully listed on the NASDAQ and just last month announced positive Phase-III results from a clinical trial which he managed. Dr. Plasse completed his medical residency at Beth Israel Hospital and fellowship in medical oncology at Mt Sinai Medical Center, both in New York. He is a graduate of the Washington University School of Medicine, St. Louis, and received his Bachelor’s in Chemistry from Brandeis University. Dr. Plasse was also a Lieutenant-Commander (Full Surgeon) in the US National Health Service Corps.