Boundless Bio to merge with Serapha; Serapha equityholders to own ~96%

Boundless Bio, Inc.

Pre-merger Serapha equityholders to own ~96.31% of combined company; Boundless Bio holders ~3.69% on fully diluted basis.
Serapha raises $138M Series A preferred and $92M PIPE concurrently with merger agreement.
Boundless Bio to cut ~75% of workforce; expects $3M-$5M in termination costs, substantially completed in Q3 2026.
CEO Zachary Hornby, CSO Christian Hassig, CMO Robert Doebele to depart July 1, 2026; Jessica Oien appointed President and PEO.
Boundless Bio discontinues BBI-940 clinical program due to poor oral bioavailability in KOMODO-1 trial.

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Executive movements

Machine-extracted from this filing. Every card cites the SEC source. See all recent executive movements.

Departed

Zachary D. Hornby

President and Chief Executive Officer

BOLD · Boundless Bio, Inc.

Effective: 2026-07-01
Successor: Jessica Oien
Filed: June 23, 2026, 8:30 AM ET

effective July 1, 2026, Zachary D. Hornby will cease his role as President and Chief Executive Officer, and as a member of the board of directors of Boundless Bio.

Appointed

Jessica Oien

President and Principal Executive Officer

BOLD · Boundless Bio, Inc.

Effective: 2026-07-01
Filed: June 23, 2026, 8:30 AM ET

effective July 1, 2026, Jessica Oien, Boundless Bio’s Chief Legal Officer and Corporate Secretary, was appointed to serve as Boundless Bio’s President and "principal executive officer," in addition to maintaining her current responsibilities as Chief Legal Officer and Corporate Secretary.

Departed

Christian Hassig

Chief Scientific Officer

BOLD · Boundless Bio, Inc.

Effective: 2026-07-01
Filed: June 23, 2026, 8:30 AM ET

effective July 1, 2026, Christian Hassig, Ph.D., will cease his role as Boundless Bio’s Chief Scientific Officer

Key facts

Extracted from this filing and checked against the source text.

Executive change SEC 8-K Item 5.02 confidence 0.95

Zachary D. Hornby departed as President and Chief Executive Officer at Boundless Bio, Inc..

Action: cease
Role: President and Chief Executive Officer

Exact text from the filing

effective July 1, 2026, Zachary D. Hornby will cease his role as President and Chief Executive Officer, and as a member of the board of directors of Boundless Bio.

View on SEC.gov

Executive change SEC 8-K Item 5.02 confidence 0.95

Jessica Oien was appointed as President and Principal Executive Officer at Boundless Bio, Inc..

Action: appointed
Role: President and Principal Executive Officer

Exact text from the filing

effective July 1, 2026, Jessica Oien, Boundless Bio’s Chief Legal Officer and Corporate Secretary, was appointed to serve as Boundless Bio’s President and "principal executive officer," in addition to maintaining her current responsibilities as Chief Legal Officer and Corporate Secretary.

View on SEC.gov

Executive change SEC 8-K Item 5.02 confidence 0.95

Christian Hassig departed as Chief Scientific Officer at Boundless Bio, Inc..

Action: cease
Role: Chief Scientific Officer

Exact text from the filing

effective July 1, 2026, Christian Hassig, Ph.D., will cease his role as Boundless Bio’s Chief Scientific Officer

View on SEC.gov

Boundless Bio, Inc. filing history →

Source: SEC EDGAR

accession 0001193125-26-278570

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