Bolt Biotherapeutics, Inc. (Nasdaq: BOLT) announced on October 23, 2026, that it has acquired Prana Therapies, Inc., a clinical-stage biotechnology company focused on next-generation half-life-extended multispecific antibodies. The stock-for-stock reverse merger positions Bolt to advance Prana's INSPIRE platform and its lead candidate PRA-216, a novel IL-4Rα/TSLP bispecific antibody. Concurrently, Bolt secured a private placement financing with US$120 million in upfront gross proceeds and warrants for up to an additional US$60 million.
Transaction and Ownership Structure
Under the stock-for-stock transaction, all outstanding equity interests of Prana were exchanged for a fixed combination of Bolt common stock and Series D non-voting convertible preferred stock. After the acquisition and concurrent private placement, former Bolt equity holders are expected to own approximately 6.9% of Bolt common stock, former Prana equity holders approximately 51.7%, and private placement investors approximately 41.4% on a fully diluted basis. The total as-converted share count will be approximately 34,183,982 shares of Bolt common stock.
Financing and Investor Participation
The private placement is expected to close on October 26, 2026, and includes participation from new and existing healthcare institutional investors. Investors include Deep Track Capital, ADAR1 Capital, Andreessen Horowitz (a16z), LYFE Capital, Coastlands Capital, Eventide Asset Management, Casdin Capital, Curie.Bio, SilverArc Capital, Soleus Capital, and Deviation Capital. Proceeds are expected to fund operations into 2028 and support multiple anticipated clinical and preclinical milestones.
PRA-216 Clinical Validation
PRA-216 is a fully human, half-life-extended bispecific antibody that targets IL-4Rα and TSLP, combining broad downstream blockade of IL-4 and IL-13 signaling with upstream TSLP inhibition. Phase 1 data presented at the 2026 European Respiratory Society showed that PRA-216 was well tolerated and produced rapid, deep, and durable activity across multiple Type 2 inflammatory biomarkers, including pSTAT6, serum TARC, blood eosinophils, and IgE. The candidate also demonstrated bioavailability and extended exposure that may support convenient at-home maintenance dosing every eight to 12 weeks.
Phase 2 Development Plans
Phase 2 development of PRA-216 has been initiated in asthma, chronic obstructive pulmonary disease (COPD), and atopic dermatitis, and a separate Phase 2 study in eosinophilic esophagitis is planned. Patient data from all four trials are expected beginning in the second quarter of 2027 and continuing through the fourth quarter of 2027. This program provides the first clinical validation of Prana's INSPIRE platform, which continues to generate additional multispecific antibody candidates.
Pipeline Expansion and Leadership
Prana's second program is an IL-31 containing bispecific antibody being developed initially for atopic dermatitis, with first-in-human studies expected to begin in the second half of 2027 and clinical data also expected in the second half of 2027. Two additional undisclosed pipeline programs are expected to advance toward IND-enabling development by the second half of 2027. Sheila Gujrathi, M.D., Prana's co-founder and former chief executive officer, has been appointed chief strategy officer of Bolt and has joined the Bolt Board of Directors.
Management Commentary
Willie Quinn, chief executive officer of Bolt Biotherapeutics, said the acquisition provides a compelling opportunity for Bolt stockholders to participate in a differentiated clinical-stage pipeline addressing large inflammatory disease markets. Sheila Gujrathi, M.D., said the transaction and financing provide resources to advance PRA-216 through multiple Phase 2 readouts in 2027 while expanding the INSPIRE pipeline. She added that PRA-216 was designed for best-in-disease efficacy together with the convenience of infrequent, at-home dosing.
Bolt Biotherapeutics will host a conference call and webcast on October 26, 2026 to discuss the transaction, financing, and pipeline. The acquisition and private placement were not subject to approval by Bolt stockholders, although stockholder approval is required for the conversion of the Series D preferred stock into common stock. With projected cash runway into 2028, Bolt is positioned to deliver multiple clinical readouts and advance its emerging pipeline of half-life-extended multispecific antibodies.