Sesen Bio Announces Inducement Grants Under Nasdaq Listing Rule 5635(c)(4)

Sesen Bio (Nasdaq: SESN), a late-stage clinical company developing targeted fusion protein therapeutics for the treatment of patients with cancer, today reported the grants of non-statutory stock options to four new employees in connection with the commencement of their employment with Sesen Bio. The addition of these new team members represents a continuation of the buildout of the Sesen Bio team in support of its transformation into a commercial-stage company ahead of the target Prescription Drug User Fee Act (PDUFA) date of August 18, 2021 for Vicineum for the treatment of BCG-unresponsive non-muscle invasive bladder cancer.

Under the grants of non-statutory stock options, up to 143,500 shares of Sesen Bio common stock are purchasable upon vesting of the stock options within the ten-year term. Each of the stock options vests over a four-year period, with one quarter of the underlying shares vesting on the first anniversary of the date of grant, and an additional 6.25% of the underlying shares vesting at the end of each successive three-month period following the one-year anniversary of the date of grant, subject in each case to the employee’s continued service with Sesen Bio.

Each of the non-statutory stock options was granted between April 5, 2021 and April 12, 2021 at exercise prices ranging from $2.32 to $2.76 per share, based on the closing price of common stock on the date of the relevant grant, and was granted outside of the Company’s 2014 Stock Incentive Plan. Each of the options was granted as a material inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4).

About Vicineum

Vicineum, a locally administered fusion protein, is Sesen Bio’s lead product candidate being developed for the treatment of BCG-unresponsive non-muscle invasive bladder cancer (NMIBC). Vicineum is comprised of a recombinant fusion protein that targets epithelial cell adhesion molecule (EpCAM) antigens on the surface of tumor cells to deliver a potent protein payload, Pseudomonas Exotoxin A. Vicineum is constructed with a stable, genetically engineered peptide tether to ensure the payload remains attached until it is internalized by the cancer cell, which is believed to decrease the risk of toxicity to healthy tissues, thereby improving its safety. In prior clinical trials conducted by Sesen Bio, EpCAM has been shown to be overexpressed in NMIBC cells with minimal to no EpCAM expression observed on normal bladder cells. Sesen Bio is currently in the follow-up stage of a Phase 3 registration trial in the US for the treatment of BCG-unresponsive NMIBC. In February 2021, the FDA accepted for filing the Company’s BLA for Vicineum for the treatment of BCG-unresponsive NMIBC and granted the application Priority Review with a PDUFA date of August 18, 2021. Additionally, Sesen Bio believes that cancer cell-killing properties of Vicineum promote an anti-tumor immune response that may potentially combine well with immuno-oncology drugs, such as checkpoint inhibitors. For this reason, the activity of Vicineum in BCG-unresponsive NMIBC is also being explored at the US National Cancer Institute in combination with AstraZeneca’s immune checkpoint inhibitor durvalumab.