Sesen Bio Announces Retirement of Leslie L. Dan

Sesen Bio (Nasdaq: SESN), a late-stage clinical company developing targeted fusion protein therapeutics for the treatment of patients with cancer, today announced that Leslie L. Dan has retired from the Company's Board of Directors, effective July 16, 2019. With the retirement of Mr. Dan, the Company’s Board of Directors will be comprised of five directors of which four are independent. The Company’s Board of Directors intends to fill the director vacancy resulting from Mr. Dan’s retirement.

“Leslie’s entrepreneurial spirit and deep pharmaceutical expertise enabled him to successfully lead the development of various anti-cancer treatments, and ultimately the potential approval of Sesen’s first product,” said Wendy L. Dixon, Chair of the Company’s Board of Directors. “On behalf of the Board and everyone at Sesen, I thank Leslie for his tremendous vision and valuable contributions to the Board and to the Company.”

“I am very pleased with the journey of the Company and the progress the Sesen team has achieved,” said Mr. Dan. “We have moved a drug development program forward into clinical trials and are now preparing to file for approval of Vicinium for the treatment of non-muscle invasive bladder cancer. I am extraordinarily proud of what we built, and I am confident the Company is well-positioned for future success.”

Mr. Dan began his career in the pharmaceutical industry in 1964 when he founded Novopharm Ltd., a pharmaceutical distribution business focused on providing less expensive generic medicines to the public. Novopharm went on to become one of Canada’s largest generic pharmaceutical companies with approximately $750 million in revenue and over 3,000 employees, before becoming part of Teva Pharmaceutical Industries Ltd. in 2000. After the successful sale of Novopharm, Mr. Dan turned his efforts and expertise to the development of anti-cancer products where his skills as a pharmacist and experience as a drug manufacturer led to the founding of Viventia Bio Inc. in 2012, where he served as president and secretary from 2012 to 2015. In 2016, Viventia was sold to what is now Sesen Bio, where Mr. Dan continued to support Sesen’s efforts by serving on the Company’s Board of Directors. Mr. Dan’s important work at Viventia led to the development of a promising early pipeline and the Company’s lead, late Phase 3 asset, Vicinium, for the treatment of non-muscle invasive bladder cancer.