Every material Form 8-K Lexeo Therapeutics, Inc. has filed with the SEC since August 12, 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.
Lexeo Therapeutics completed its merger with Mantle Therapeutics, under a merger agreement dated September 16, 2026. Mantle shareholders received $5.3 million in cash, subject to adjustments, and $3 million in Lexeo common stock, and the stock was issued without SEC registration. Additional contingent payments of $1 million in cash and up to $12 million in milestone payments may never become payable.
Upfront consideration: $5.3 million in cash, subject to certain adjustments, plus $3 million in Lexeo common stock
Lexeo common stock issued in the merger was not registered and relied on Section 4(a)(2) and/or Regulation D exemptions
Contingent payments: a one-time $1 million cash payment and up to $12 million in development and regulatory milestone payments over a 12-year term
Merger agreement dated September 16, 2026, among Lexeo, Mantle Therapeutics Inc., Magma Merger Sub Inc. and Shareholder Representative Services LLC
Lexeo Therapeutics signed a merger agreement on September 16, 2026, to acquire private clinical-stage company Mantle Therapeutics, paying $8.3 million upfront in cash and stock, with up to $13.0 million more in contingent payments. The company also announced three research collaborations on cerebellar-targeted frataxin gene therapy and said cash runway guidance into 2028 is unchanged.
Upfront consideration: $5.3 million in cash, subject to adjustments, and $3.0 million in Lexeo common stock
Contingent payments: an additional $1.0 million in cash and up to $12.0 million in milestones, none guaranteed; total potential consideration is $21.3 million per the press release
Closing requires Requisite Stockholder Approval; Key Stockholders holding about 76.1% of Mantle capital stock agreed to support the deal; either party may terminate if the merger is not completed by November 16, 2026
The press release expects closing in the third quarter of 2026 and states the deal is funded within existing balance sheet capacity
Lexeo Therapeutics reported second quarter 2026 results, with a net loss of $25.9 million, nearly flat from $26.1 million a year earlier, while the per-share loss fell to $0.30 from $0.60 on a larger share count. The company said it began its SUNRISE-FA 2 pivotal trial for LX2006 in June 2026 and had $234.2 million in cash, cash equivalents and investments, which it expects to fund operations into 2028.
Q2 2026 net loss was $25.9 million, or $0.30 per share, versus $26.1 million, or $0.60 per share, in Q2 2025; weighted average shares rose to 85,626,751 from 43,573,628.
Research and development expenses rose to $19.0 million from $14.7 million, while general and administrative expenses fell to $9.0 million from $16.0 million.
Cash, cash equivalents and investments were $234.2 million at June 30, 2026, down from $246.6 million at December 31, 2025.
The FDA granted RMAT designation for LX2020 in August 2026; topline data for LX2006 are expected in the second half of 2027.
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