Werewolf Therapeutics and Ambros Therapeutics have entered into a definitive all-stock merger agreement alongside an oversubscribed $150 million private placement that is expected to fund development of neridronate through pivotal Phase III results and a planned FDA submission.
The combined company will operate as Ambros Therapeutics, be headquartered in San Diego and is expected to trade on Nasdaq under the ticker symbol AMBX.
The company will focus primarily on advancing neridronate for Complex Regional Pain Syndrome Type 1, or CRPS-1, a debilitating orphan disease affecting an estimated 65,000 newly diagnosed patients annually in the U.S. for which there is currently no FDA-approved drug therapy.
Neridronate is a differentiated bisphosphonate already approved and marketed in Italy for CRPS and other indications and has been administered to approximately 600,000 patients across its approved uses.
The drug has received FDA Breakthrough Therapy, Fast Track and Orphan Drug designations for CRPS.
Ambros is currently evaluating neridronate in the pivotal CRPS-RISE Phase III trial.
The multicenter, randomized, triple-blind and placebo-controlled trial is expected to enroll approximately 270 patients with warm CRPS-1 and evaluate intravenous neridronate against placebo.
Its primary endpoint measures the change in pain intensity from baseline through week 12 using an 11-point Numerical Rating Scale.
Ambros is taking a precision-medicine approach by focusing on recently diagnosed patients with warm-phase CRPS-1 and positive triple-phase bone scans, a population whose disease biology the company believes most closely aligns with neridronate’s mechanism.
Based on discussions with the FDA, Ambros believes a successful single pivotal study could potentially support U.S. approval, although regulatory approval is not guaranteed.
Topline data from CRPS-RISE are expected in 2028.
Ambros said its intellectual property portfolio, together with orphan-drug protections, could provide potential U.S. market exclusivity for neridronate through 2045.
The concurrent $150 million private placement is co-led by RA Capital Management and Janus Henderson Investors.
Other investors include Aberdeen Investments, Adage Capital Partners, ADAR1 Capital Management, Affinity Asset Advisors, Arkin Bio Capital, Balyasny Asset Management, Enavate Sciences, SilverArc Capital, Sphera Healthcare and Woodline Partners, along with additional new and existing investors.
Werewolf will issue common stock and pre-funded warrants for approximately $150 million in gross proceeds when the financing closes concurrently with the merger.
Ambros expects the combined company’s capital resources to fund operations through the expected CRPS-RISE topline results, a planned New Drug Application submission and preparations for potential commercialization, with cash runway extending into the first half of 2029.
The merger assigns Ambros an implied value of $500 million before the private placement and Werewolf an implied value of $47.5 million.
Pre-merger Ambros shareholders are expected to own approximately 71.7% of the combined company.
Investors participating in the private placement are expected to own approximately 21.5%, while existing Werewolf shareholders other than PIPE participants are expected to own approximately 6.8%.
Those ownership percentages remain subject to adjustments based partly on Werewolf’s net cash at closing.
Existing Werewolf shareholders will also receive a contingent value right providing potential payments from certain future net proceeds associated with dispositions of Werewolf’s legacy assets.
Werewolf has historically focused on immuno-oncology through its PREDATOR platform and conditionally activated INDUKINE molecules, including clinical-stage WTX-124 and WTX-330.
The merger follows Werewolf management and its board conducting a review of strategic alternatives.
Following closing, Ambros’ existing leadership team will lead the combined company, including Joseph “Jay” Hagan as CEO, Cris Calsada as CFO, Gail Cawkwell as Chief Medical Officer, Christopher Aker as General Counsel and Kunal Kishnani as SVP of Corporate Development.
The companies expect the transaction to close by the first quarter of 2027, subject to shareholder approvals, Nasdaq listing approval, effectiveness of the Form S-4 registration statement and other customary conditions.
Support: Leerink Partners, Piper Sandler, Cantor, Wells Fargo Securities and LifeSci Capital are serving as placement agents for the private placement. And Piper Sandler is also serving as exclusive financial advisor to Werewolf.
KEY QUOTES:
“We are uniquely positioned to be advancing neridronate, a differentiated bisphosphonate with extensive prior clinical experience, in an FDA-aligned single Phase 3 trial supporting potential regulatory approval in patients with CRPS-1, a debilitating orphan disease with no currently FDA-approved therapy.”
“With the capital raised through this financing from a leading investor syndicate, we expect to be fully funded through potentially value-generating topline results of our pivotal CRPS-RISE Phase 3 trial and have the resources to advance a potential NDA submission and commercial preparations.”
Joseph “Jay” Hagan, CEO Of Ambros Therapeutics
“Following a comprehensive review of strategic options, management and the board of directors believe a merger with Ambros Therapeutics is in the best interest of Werewolf Therapeutics’ stockholders. The Ambros management team’s extensive track record, drug development expertise and the potential of neridronate to deliver a meaningful treatment to patients with CRPS-1 is very compelling.”
“Neridronate, which has received the FDA’s Breakthrough Therapy, Fast Track, and Orphan Drug designations, is a differentiated bisphosphonate with the potential to redefine the standard of care for patients with CRPS-1.”
Daniel J. Hicklin, Ph.D., President And CEO Of Werewolf Therapeutics
