{"filing":{"accession_number":"0001193125-26-390577","cik":"0002036042","ticker":"SION","company_name":"Sionna Therapeutics, Inc.","form":"8-K","filing_date":"2026-09-14","report_date":"2026-09-09","primary_document":"d148638d8k.htm","primary_document_url":"https://www.sec.gov/Archives/edgar/data/2036042/000119312526390577/d148638d8k.htm"},"events":[{"id":33268,"run_id":30589,"accession_number":"0001193125-26-390577","anchor_item_number":"2.05","event_type":"workforce_reduction","event_domain":"operational","is_material":true,"confidence":0.95,"summary":"Sionna's Board approved a restructuring plan involving a 46% workforce reduction and wind-down of the SION-719 program, with estimated aggregate charges of $6.4 million ($5.3 million in severance, $0.7 million in contract close-out costs, and $0.4 million in stock-based compensation), extending cash runway into H2 2029.","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14","form":"8-K","submitted_at":null,"items":[{"id":36666,"accession_number":"0001193125-26-390577","item_number":"2.05","item_title":null,"event_type":"workforce_reduction","event_domain":"operational","is_material":true,"confidence":0.95,"reasoning":"The Item 2.05 disclosure describes a Board-approved restructuring plan involving a 46% workforce reduction and wind-down of the SION-719 program, with estimated aggregate charges of $6.4 million ($5.3 million in severance, $0.7 million in contract close-out costs, and $0.4 million in stock-based compensation). This is a classic workforce reduction event with associated exit costs, materially affecting the company's operational structure and cash runway extension into H2 2029.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"","ticker":null,"filing_date":""}]},{"id":33269,"run_id":30589,"accession_number":"0001193125-26-390577","anchor_item_number":"5.02","event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.75,"summary":"Caroline Stark Beer, Chief Business Officer, was terminated without cause effective September 15, 2026, in connection with the restructuring, with severance benefits and extended health coverage.","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14","form":"8-K","submitted_at":null,"items":[{"id":36667,"accession_number":"0001193125-26-390577","item_number":"5.02","item_title":null,"event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.75,"reasoning":"Caroline Stark Beer, Chief Business Officer, was terminated without cause effective September 15, 2026, in connection with a restructuring. While the Item 5.02 also discloses role expansions for other officers and an option repricing, the principal disclosed action is the departure of a named executive officer. The severance benefits and extended health coverage indicate materiality to investors assessing executive stability during a significant restructuring.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"","ticker":null,"filing_date":""}]},{"id":33270,"run_id":30589,"accession_number":"0001193125-26-390577","anchor_item_number":"8.01","event_type":"operational_other","event_domain":"operational","is_material":true,"confidence":0.75,"summary":"Sionna announced plans to advance SION-451 + SION-2222 into Phase 2a clinical trials based on post hoc analysis of prior trial data, a material strategic milestone for the clinical-stage biopharmaceutical company.","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14","form":"8-K","submitted_at":null,"items":[{"id":36668,"accession_number":"0001193125-26-390577","item_number":"8.01","item_title":null,"event_type":"operational_other","event_domain":"operational","is_material":true,"confidence":0.75,"reasoning":"Sionna announced plans to advance SION-451 + SION-2222 into Phase 2a clinical trials, a material operational and strategic milestone for a clinical-stage biopharmaceutical company. The disclosure also includes a 46% workforce reduction with ~$6.4 million in restructuring charges and extended cash runway to H2 2029. While the workforce reduction could be classified as `workforce_reduction`, the primary focus of the announcement is the strategic decision to advance the dual combination program based on post hoc analysis of prior trial data, making this fundamentally an operational/strategic business decision rather than a restructuring event.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"","ticker":null,"filing_date":""}]}],"classifications":[{"id":36666,"accession_number":"0001193125-26-390577","item_number":"2.05","item_title":null,"event_type":"workforce_reduction","event_domain":"operational","is_material":true,"confidence":0.95,"reasoning":"The Item 2.05 disclosure describes a Board-approved restructuring plan involving a 46% workforce reduction and wind-down of the SION-719 program, with estimated aggregate charges of $6.4 million ($5.3 million in severance, $0.7 million in contract close-out costs, and $0.4 million in stock-based compensation). This is a classic workforce reduction event with associated exit costs, materially affecting the company's operational structure and cash runway extension into H2 2029.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14"},{"id":36667,"accession_number":"0001193125-26-390577","item_number":"5.02","item_title":null,"event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.75,"reasoning":"Caroline Stark Beer, Chief Business Officer, was terminated without cause effective September 15, 2026, in connection with a restructuring. While the Item 5.02 also discloses role expansions for other officers and an option repricing, the principal disclosed action is the departure of a named executive officer. The severance benefits and extended health coverage indicate materiality to investors assessing executive stability during a significant restructuring.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14"},{"id":36668,"accession_number":"0001193125-26-390577","item_number":"8.01","item_title":null,"event_type":"operational_other","event_domain":"operational","is_material":true,"confidence":0.75,"reasoning":"Sionna announced plans to advance SION-451 + SION-2222 into Phase 2a clinical trials, a material operational and strategic milestone for a clinical-stage biopharmaceutical company. The disclosure also includes a 46% workforce reduction with ~$6.4 million in restructuring charges and extended cash runway to H2 2029. While the workforce reduction could be classified as `workforce_reduction`, the primary focus of the announcement is the strategic decision to advance the dual combination program based on post hoc analysis of prior trial data, making this fundamentally an operational/strategic business decision rather than a restructuring event.","classifier_version":"claude-haiku-4-5-20251001+prompt-a85dd512","taxonomy_version":"v1.3","classified_at":"2026-09-14T20:11:49.244072+00:00","company_name":"Sionna Therapeutics, Inc.","ticker":"SION","filing_date":"2026-09-14"}]}