Bolt Biotherapeutics (NASDAQ:BOLT) said it has acquired Prana Therapies through a stock-for-stock reverse merger and entered into a concurrent private placement expected to provide $120 million in upfront gross proceeds, with up to an additional $60 million available if accompanying warrants are exercised.
President and Chief Executive Officer Willie Quinn said Prana’s pipeline will become the company’s primary development focus following the transaction. The company said the financing is expected to fund operations into 2028 and support clinical and preclinical milestones, including planned Phase II proof-of-concept data for lead candidate PRA-216 beginning in the second quarter of 2027.
Subject to stockholder approval, non-voting convertible preferred stock issued in connection with the transaction and financing is expected to convert into Bolt common stock after a planned stockholder vote. Prana Co-Founder and Chief Executive Officer Dr. Sheila Gujrathi has been appointed Bolt’s chief strategy officer and joined the company’s board of directors.
Focus shifts to multispecific antibody pipeline
Gujrathi said the combined company will focus on Prana’s INSPIRE platform, which produces half-life extended multispecific antibodies initially aimed at immunology and inflammation. The platform uses a fully human IgG-based architecture designed to support stability, manufacturability, high-concentration subcutaneous formulations and lower immunogenicity risk, according to the company.
The lead program, PRA-216, is a bispecific antibody targeting IL-4 receptor alpha and thymic stromal lymphopoietin, or TSLP. The candidate is in Phase II development for asthma, chronic obstructive pulmonary disease and atopic dermatitis. Bolt also plans a Phase II study in eosinophilic esophagitis.
The company expects patient proof-of-concept data across the four studies to begin in the second quarter of 2027 and continue through the fourth quarter. Bolt said the studies are intended to inform Phase III trial design, while Phase III-enabling activities are already progressing in parallel. The company expects to be positioned to begin pivotal trials in early 2028.
Prana’s second program is an IL-31-containing bispecific antibody initially being developed for atopic dermatitis. The company expects to move that candidate into the clinic and generate initial clinical data during the second half of 2027. Two additional wholly owned programs are expected to advance through IND-enabling development in the same period.
Phase I findings supported Phase II advancement
Chief Medical Officer Hector Ortega said the Phase I study of PRA-216 enrolled 57 healthy volunteers in a randomized, double-blind, placebo-controlled single- and multiple-ascending-dose design. The study evaluated intravenous and subcutaneous administration across a range of doses. Participants in the multiple-dose cohort received doses at weeks zero, two and four, establishing the induction regimen now being used in Phase II.
As of a Sept. 1 data cutoff, Ortega said there were no serious adverse events, adverse events of special interest, Grade 3 or greater treatment-emergent adverse events, injection-site reactions, local pain or conjunctivitis reported in the study.
Chief Scientific Officer Ryan Sullivan said a single intravenous dose produced more than 16 weeks of exposure, while a single subcutaneous dose showed 85% bioavailability. Following the three-dose subcutaneous induction regimen, exposure extended beyond 20 weeks, according to the company.
Among 43 PRA-216-treated participants, one developed a low-titer anti-drug antibody response, representing a 2.3% incidence, Sullivan said. The company also reported pharmacodynamic activity at the 600-milligram multiple-dose regimen, including a median decline of about 50% in serum TARC through week 12, rapid and sustained reductions in blood eosinophils through week 12, and an approximately 25% decline in serum IgE.
Every-eight-week maintenance regimen under evaluation
Bolt is evaluating a 600-milligram maintenance dose every eight weeks in its Phase II trials. Sullivan said simulations based on Phase I pharmacokinetic data indicated exposure could remain above the company’s target thresholds for both targeted pathways under that regimen.
The company said it may assess every-12-week dosing in future studies. Gujrathi said the intended product profile is aimed at potentially providing deeper and more durable efficacy than single-target approaches, broader coverage across type 2 inflammatory diseases and a convenient at-home auto-injector maintenance regimen.
Quinn said the company believes the combination provides a path forward for Bolt and its stockholders, while Gujrathi said the financing and public-company structure are intended to support the pipeline through a data-rich period ahead.
About Bolt Biotherapeutics (NASDAQ:BOLT)
Bolt Biotherapeutics, Inc is a clinical-stage biotechnology company focused on developing immunotherapies for cancer. The company’s research is based on its Boltbody Immune-Stimulating Antibody Conjugate (ISAC) platform, which is designed to combine the tumor-targeting ability of antibodies with agents that activate the innate immune system.
Bolt’s approach is intended to recruit and stimulate immune cells within the tumor microenvironment, potentially helping the body recognize and attack cancer cells.
