R&D Day for Investors and Analysts November 16, 2020 Seagen 2020 R&D Day Clay Siegall, Ph.D. President & Chief Executive Officer Roger Dansey, M.D. Chief Medical Officer Shyra Gardai, Ph.D. Executive Director, Immunology Nancy Whiting, Pharm.D EVP, Corporate Strategy Alliances and Communications Megan O'Meara, M.D. VP, Early Stage Development 2 Forward-Looking Statements Certain of the statements made in this presentation are forward looking, such as those, among others, relating to the Company's potential ...

J.P. Morgan Healthcare Conference Clay Siegall, Ph.D. President and Chief Executive Officer January 11, 2021 2 Key 2020 Accomplishments Set Foundation for Continued Growth CONFIDENTIAL Forward-Looking Statements Certain of the statements made in this presentation are forward looking, such as those, among others, relating to the Company's potential to achieve the noted development and regulatory milestones in 2021 and in future periods; anticipated activities related to the Company's planned and ongoing clin ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 0-32405 SEAGEN INC. (Exact name of registrant as specified in its charter) Delaware 91-1874389 Indicate by che ...

Table of Contents For the transition period from to Commission file number 0-32405 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 SEAGEN INC. (Exact name of registrant as specified in its charter) Delaware 91-1874389 (State or other juri ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 0-32405 SEAGEN INC. (Exact name of registrant as specified in its charter) Delaware 91-1874389 (State or other jur ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 0-32405 SEAGEN INC. (Exact name of registrant as specified in its charter) (State or other Jurisdiction of incorporation or organization ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) 21823 30th Drive SE Bothell, Washington 98021 ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 0-32405 SEAGEN INC. (Exact name of registrant as specified in it ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to For the quarterly period ended June 30, 2022 OR Commission file number 0-32405 SEAGEN INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorpor ...

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) SEAGEN INC. (Exact name of registrant as specified in its charter) Delaware 91-1874389 (State or other jurisdiction of incorporation or o ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Table of Contents Washington, D.C. 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 0-32405 SEAGEN INC. (Exact name of registrant as specified in its charter) (State or other Jurisdiction of incorporati ...