seser b i o June 2019 Regulatory Update June 10, 2019 NASDAQ SESN FORWARD-LOOKING STATEMENTS This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this presentation, including statements regarding our strategy, future operations, clinical development of our protein therapies, timing or probability of regulatory approval, future financial position, future revenues, projected costs, prospe ...

Financial Data and Key Metrics Changes - The company finished the quarter with a strong balance sheet and cash runway into 2020, having filed its Form 10-Q on May 10 [14] - The average patient treated with Vicinium is projected to remain cystectomy-free for approximately 28 months based on Kaplan-Meier estimates [31] Business Line Data and Key Metrics Changes - The updated Phase III clinical data demonstrate a significant and reproducible complete response rate for carcinoma in situ patients, with a 25% complete response rate at 12 months for those who received 7 to 10 installations of BCG [20] - The average time to cystectomy for patients in the trial is approximately 29 months, indicating a compelling delay in the need for radical cystectomy [94] Market Data and Key Metrics Changes - The company has conducted market research among patients, physicians, and payers, indicating a strong potential for advocacy and demand across all key customer segments [41] - The opportunity for Vicinium outside the U.S. is estimated to be larger than the domestic market, with significant potential in regions such as Europe and Asia [46] Company Strategy and Development Direction - The company aims to bring Vicinium to market quickly to address the urgent need due to BCG shortages, with a focus on regulatory and commercial probability of success [11][12] - The commercial strategy includes value-based pricing contracts, with a focus on setting a price benchmark and sharing risk with payers [71] Management's Comments on Operating Environment and Future Outlook - Management emphasized the importance of the time to cystectomy data as a compelling factor for physicians and payers, highlighting the high costs associated with radical cystectomy [92] - The company is confident in its ability to realize the commercial opportunity if Vicinium is approved, with ongoing discussions with the FDA to ensure alignment on regulatory pathways [48][86] Other Important Information - The company has two upcoming face-to-face meetings with the FDA, including a type C meeting on May 20 and a type B pre-BLA meeting on June 6 [14][15] - The safety and tolerability profile of Vicinium is favorable compared to existing therapies, with a low rate of treatment-related adverse events [36] Q&A Session Summary Question: Can you discuss the time to cystectomy data in relation to VALSTAR? - Management explained that the time to cystectomy data shows an average delay of 28 months, which is significant for both physicians and payers, and emphasized the importance of the responder versus nonresponder ratio [57][58] Question: What are the thoughts on value-based pricing? - Management confirmed that they are exploring value-based contracts and are in discussions with payers about pricing benchmarks, aiming to negotiate contracts that share risk [71] Question: What are the key data points for FDA approval and commercialization? - Management highlighted that the risk-benefit profile, time to cystectomy data, and durability of response are critical for both FDA approval and commercial success [90][92] Question: Is there a need for an Advisory Committee meeting? - Management indicated that it is unlikely an ADCOM will be required due to the straightforward nature of the data set, but this will be assessed closer to the BLA submission [97]

seser b i o 1Q 2019 Business Update NASDAQ SESN May 13, 2019 FORWARD-LOOKING STATEMENTS This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this presentation, including statements regarding our strategy, future operations, clinical development of our protein therapies, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forwar ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to | --- | --- | |----------------------------------------------------------------------------|------------------------------------------| | ...

Sesen Bio, Inc. (NASDAQ:SESN) Q4 2018 Earnings Conference Call March 4, 2019 8:00 AM ET Company Participants Erin Clark - Executive Director, Strategic Planning & Investor Relations Thomas Cannell - President and Chief Executive Officer Dennis Kim - Chief Medical Officer Richard Fitzgerald - Chief Financial Officer Chad Myskiw - Head of Global CMC Project Management. Conference Call Participants John Newman - Canaccord Genuity Yale Jen - Laidlaw Capital Markets Swayampakula Ramakanth - H.C. Wainwright C ...

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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to | --- | --- | |----------------------------------------------------------------------------|------------------------------------------| | Comm ...