Every material Form 8-K Sionna Therapeutics, Inc. has filed with the SEC since August 06, 2026, read and summarized by AI: what happened, the key figures, whether it reads positive or negative for shareholders, and how big a deal it is (impact 1-5). Newest first; each brief links to its own page and to the filing on SEC.gov.
Sionna Therapeutics said its Board approved a restructuring on September 9, 2026, that cuts about 46% of its workforce and winds down the SION-719 add-on program, with aggregate charges currently estimated at about $6.4 million. The company said the changes are meant to focus resources on the SION-451 and SION-2222 dual combination and extend its cash runway into the second half of 2029. Its Chief Business Officer's employment is ending, and the company is repricing employee stock options.
Restructuring charges are estimated at about $6.4 million, including $5.3 million in employee severance and other post-employment benefits, $0.7 million in SION-719 contract close-out costs and $0.4 million in stock-based compensation.
Workforce reduction and vendor wind-down are expected to be substantially complete by the end of the third quarter of 2026.
The company had about $268.3 million in cash, cash equivalents and marketable securities at the end of Q2 2026, and expects its runway to extend into the second half of 2029.
Chief Business Officer Caroline Stark Beer's employment ends September 15, 2026; option repricing takes effect September 17, 2026.
Sionna Therapeutics reported that its Phase 2a PreciSION CF trial of SION-719 added to standard of care did not meet its key activity endpoint, and the company will not advance SION-719 as an add-on. The company identified SION-451 with SION-2222 as the preferred dual combination from a Phase 1 healthy volunteer study, and it plans to preserve capital while it evaluates next steps.
PreciSION CF Phase 2a trial showed a -1.0 mmol/L mean placebo-adjusted sweat chloride change (p=0.7), missing the key activity endpoint.
Company is not advancing SION-719 as an add-on to standard of care; topline data were received Friday, August 7, 2026.
Phase 1 trial identified SION-451 + SION-2222 as the preferred dual combination; 120 participants were dosed across both dual combinations.
Sionna ended Q2 with approximately $268.3 million in cash, cash equivalents and marketable securities and plans actions to preserve capital.
Sionna Therapeutics reported a second-quarter 2026 net loss of $29.9 million, up from $18.1 million a year earlier, as research and development and general and administrative expenses both rose. The company had $268.3 million in cash, cash equivalents and marketable securities at June 30, 2026, which it expects will fund operations into 2028, and it reiterated that topline data from two clinical trials are on track for summer 2026.
Net loss was $29.9 million for Q2 2026, compared with $18.1 million for Q2 2025.
Research and development expenses rose to $21.9 million from $15.4 million; general and administrative expenses rose to $10.6 million from $6.5 million.
Cash, cash equivalents and marketable securities totaled $268.3 million at June 30, 2026, down from $310.3 million at December 31, 2025.
Topline data from the PreciSION CF Phase 2a trial of SION-719 and the Phase 1 dual combination trial of SION-451 are expected in summer 2026.
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