Ambros Therapeutics Announces Planned Interim Analysis of Phase 3 Clinical Trial Following FDA Feedback
Company plans group sequential design with an interim analysis that could allow the trial to stop early Neridronate
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Company plans group sequential design with an interim analysis that could allow the trial to stop early
Neridronate has received FDA Breakthrough Therapy, Fast Track, and Orphan Drug designations
SAN DIEGO, Oct. 26, 2026 (GLOBE NEWSWIRE) — Ambros Therapeutics, Inc., today announced it has reached alignment with the U.S. Food and Drug Administration (FDA) regarding Ambros’ proposal to incorporate an interim analysis with a group sequential design in the ongoing pivotal Phase 3 CRPS-RISE trial evaluating neridronate for the treatment of complex regional pain syndrome type 1 (CRPS-1). The interim analysis could permit the trial to be stopped early if warranted. The interim analysis is expected to be performed when half of the study participants have completed the study. The process would be managed via an independent data monitoring committee and governed by a prespecified statistical analysis plan that the Company plans to align on with the FDA. Ambros intends to modify the CRPS-RISE protocol to reflect the planned interim analysis and to submit a revised statistical analysis plan and a Data Monitoring Committee charter for FDA review.
“CRPS-1 is a debilitating and painful condition that affects an estimated 65,000 newly diagnosed people in the United States each year, and there are currently no FDA-approved medicines,” said Jay Hagan, Chief Executive Officer of Ambros Therapeutics. “An interim analysis gives CRPS-RISE the potential to reach a decision earlier than the full trial would otherwise require. We appreciate the FDA’s engagement and look forward to working closely with them as the trial progresses.”
“We appreciate FDA’s engagement on the interim analysis as this is a way to potentially bring a much-needed treatment for this severe and painful chronic disease to US patients meaningfully earlier,” said Gail Cawkwell, M.D., Ph.D., Chief Medical Officer of Ambros Therapeutics. “Our ongoing CRPS-RISE trial builds on a number of earlier studies in Italy and globally that contribute to the robust information available to support our planned FDA filing.”
More information about CRPS-RISE Phase 3 Clinical Trial is available on the clinical trial website (CRPS-RISE) and at clinicaltrials.gov (NCT07210515).
About Neridronate
Neridronate is a differentiated bisphosphonate that was developed by Abiogen Pharma S.p.A. Neridronate is approved and marketed in Italy for the treatment of Complex Regional Pain Syndrome (“CRPS”); clinical studies have demonstrated lasting pain reduction along with improvements in other CRPS related symptoms. Beyond CRPS, neridronate is also approved in Italy for osteogenesis imperfecta and Paget’s disease and has been administered to approximately 600,000 patients across approved indications. Its well-established safety and tolerability profile and therapeutic benefits make it a potential promising treatment for patients with CRPS-1 worldwide. Recognizing its potential, the FDA has granted neridronate Breakthrough Therapy, Fast Track, and Orphan Drug designations for the treatment of CRPS.
About Complex Regional Pain Syndrome Type 1 (CRPS-1)
CRPS-1 is a severely painful, debilitating orphan disease typically following a limb injury affecting an estimated 65,000 newly diagnosed people in the United States each year. There are currently no FDA-approved medicines available to treat this high unmet need patient population. The condition is characterized by intense pain that can be continuous in the affected limb such as the arm, leg, hand or foot. Patients with CRPS-1 often experience an evolving condition commencing with a “warm” phase that typically predominates in the first year after onset where inflammation and other mechanisms cause the affected limb to become red, swollen, warm, and hypersensitive to pain. In many patients, the disease progresses to a chronic “cold” phase, where the affected limb changes its presentation and patients face ongoing, debilitating pain.
About CRPS-RISE
CRPS-RISE is a Phase 3, multicenter, randomized, triple-blind, placebo-controlled clinical trial designed to assess the efficacy, safety and tolerability of neridronate in patients with warm CRPS-1. The trial will evaluate approximately 270 participants randomized 1:1 to receive either intravenous (“IV”) neridronate or placebo. An interim analysis will be performed after half of participants have completed the trial. To be eligible for the trial, participants must have a confirmed CRPS-1 diagnosis per the Budapest Clinical Criteria, a known precipitating event (e.g. fracture, sprain, contusion), CRPS-1 duration of 6 months or less and moderate to severe pain. Additionally, participants must have characteristics that Ambros Therapeutics believes make them more likely responders to neridronate treatment: a positive triple phase bone scan and specific attributes of the warm CRPS-1 subtype. Following an initial screening period of two to six weeks, participants will receive four IV infusions over 10 days of either 100 mg neridronate (400 mg total dose) or placebo followed by a post-treatment period through week 12. The primary efficacy endpoint is change in pain intensity from baseline to week 12 as measured on an 11-point Numerical Rating Scale. Key secondary endpoints include other measures of pain reduction and patient reported outcomes. The program includes a registry for long-term outcomes and an opportunity for CRPS-RISE participants with active disease who completed the study to receive neridronate in an open-label study.
About Ambros Therapeutics
Ambros Therapeutics, headquartered in San Diego, California, is a clinical-stage biotechnology company focused on the development of innovative and transformative medicines for diseases with high unmet medical need. Ambros’ lead investigational program, neridronate, is currently being evaluated in an ongoing pivotal Phase 3 clinical trial (CRPS-RISE) for warm CRPS-1. Neridronate has the potential to become the first FDA-approved pharmacological therapy addressing patients with CRPS-1. For more information visit https://ambrostherapeutics.com/ or follow the company on LinkedIn.
Forward-Looking Statements
This press release contains forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995, including, without limitation, statements regarding: Ambros’ plans to incorporate an interim analysis in the ongoing CRPS-RISE Phase 3 clinical trial evaluating neridronate as a potential treatment for CRPS-1; the process for managing, and the potential implications of, the interim analysis, including the possible early conclusion of the clinical trial; Ambros’ ability to reach alignment with FDA on the prespecified statistical analysis plan; and other statements that are not historical facts. The words “advance,” “could,” “forward,” “future,” “ongoing,” “plan,” “potential” or “promising,” or the negative of these terms, or other comparable terminology are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. These statements are subject to a number of risks, uncertainties and assumptions, including, but not limited to: uncertainties associated with the clinical development and regulatory approval of neridronate, including potential delays in the commencement, enrollment and completion of clinical trials; uncertainties related to the FDA’s interpretation of results from clinical trials; risks related to the inability of Ambros to obtain sufficient additional capital to continue to advance neridronate; and uncertainties regarding Ambros’ abilities to achieve its long-term goals and capitalize on opportunities. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties. You should not place undue reliance on these forward-looking statements, which are made only as of the date hereof. Ambros expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.
Company Contact
Argot Partners
ambros@argotpartners.com
212-600-1902
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