Ambros Therapeutics Plans Interim Analysis for CRPS-RISE Trial

SAN DIEGO, Oct. 26, 2026 /CourierPR/ -- Ambros Therapeutics, a clinical-stage biotechnology company based in San Diego, California, has announced plans to incorporate an interim analysis with a group sequential design in its ongoing pivotal Phase 3 CRPS-RISE clinical trial. This move, which follows alignment with the U.S. Food and Drug Administration (FDA), could potentially allow the trial to stop early if warranted. The interim analysis is expected to be performed when half of the study participants have completed the trial.

CRPS-RISE, a Phase 3, multicenter, randomized, triple-blind, placebo-controlled clinical trial, is evaluating the efficacy, safety, and tolerability of neridronate for the treatment of warm Complex Regional Pain Syndrome type 1 (CRPS-1). The trial will assess approximately 270 participants, who will be randomized 1:1 to receive either intravenous (IV) neridronate or placebo. Participants will receive four IV infusions over 10 days, with a total dose of 400 mg of neridronate, administered in 100 mg doses. The post-treatment period will extend through week 12.

The primary efficacy endpoint of the trial is the 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 CRPS-RISE trial is registered at clinicaltrials.gov (NCT07210515).

Neridronate, a bisphosphonate developed by Abiogen Pharma S.p.A., has received FDA Breakthrough Therapy, Fast Track, and Orphan Drug designations for the treatment of CRPS-1. The drug is currently approved and marketed in Italy for the treatment of CRPS-1, with a well-established safety and tolerability profile. It has been administered to approximately 600,000 patients across approved indications, making it a potential promising treatment for patients with CRPS-1 worldwide.

CRPS-1 is a debilitating and painful condition that affects 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, typically commencing with a "warm" phase that 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.

The CRPS-RISE trial is part of a broader program that 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.