{"schema_version":"secwatch.filing_event.v1","accession":"0001104659-23-040172","form_type":"8-K","ticker":null,"cik":"0001442836","company_name":"Mersana Therapeutics, Inc.","filed_at":"2023-03-31T23:59:59+00:00","discovered_at":"2026-05-14T18:03:45.020583+00:00","generated_at":"2026-06-17T07:45:12.727692+00:00","sec_items":["5.03","9.01"],"event_type":"other","sentiment":"neutral","materiality_score":0.05,"calibrated_materiality_score":0.05,"confidence":"high","headline":"Mersana Therapeutics adopts amended bylaws with universal proxy rule updates","bullets":["Board adopted Second Amended and Restated Bylaws on March 31, 2023, effective immediately.","Enhanced disclosure and procedural requirements for stockholder director nominations, aligning with SEC universal proxy rules.","Requires proof of compliance with Rule 14a-19; non-compliance allows disregarding nominations and votes.","Limits stockholder nominees to number of directors to be elected; removes stockholder list display during remote meetings.","Added emergency bylaw provision and other conforming changes to Delaware General Corporation Law."],"urls":{"canonical":"https://secwatch.observer/filing/0001104659-23-040172","json":"https://secwatch.observer/filing/0001104659-23-040172.json","markdown":"https://secwatch.observer/filing/0001104659-23-040172.md","text":"https://secwatch.observer/filing/0001104659-23-040172.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/1442836/000110465923040172/0001104659-23-040172-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/1442836/000110465923040172/tm2311091d1_8k.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-06-17T07:45:12.727692+00:00"},"review":{"review_status":"machine_generated","human_reviewed":false,"corrected":false,"correction_note":null,"correction_timestamp":null,"superseded_by":null,"related_filings":[]},"source_grounded_claims":[{"claim_id":"c8eb59dd71af85c83567c23d31b9952a65a19aa8","claim":"Mersana Therapeutics, Inc.: Amended and restated bylaws to adopt universal proxy rules, revise stockholder meeting procedures, add emergency bylaw provision, and make other updates (effective 2023-03-31).","evidence_excerpt":"On March 31, 2023 , the Board of Directors (the “Board”) of Mersana Therapeutics, Inc. (the “Company”) adopted and approved the Company’s Second Amended and Restated Bylaws (as so amended and restated, the \"Bylaws\").","evidence_source":"SEC 8-K Item 5.03/5.05/5.06","evidence_url":"https://www.sec.gov/Archives/edgar/data/1442836/000110465923040172/0001104659-23-040172-index.htm","confidence":0.9,"family_label":"Governance Changes","details":[{"label":"Change","value":"bylaw amendment"},{"label":"Effective","value":"2023-03-31"}],"fact_type":"governance_change"}],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}