Evaluation of IV AMBTX-01 (Neridronate) for Treatment of CRPS Type 1 (CRPS-RISE)

NCT07210515 | Recruiting Phase 3 FDA Drug

• 1 other identifier: AMBTX-01-301
• Study Type: interventional
• Target: 270
• Locations: 1 country
• Sites: 6

Brief Summary

Phase 3 Trial of AMBTX-01 (neridronate) for Complex Regional Pain Syndrome Type 1

Conditions

Complex Regional Pain Syndrome Type I

Keywords

CRPS; edema; pain; RDS

Outcome Measures

Primary Outcomes (1)

• Change in pain intensity from baseline to Week 12.

  Assessed on an 11-point Numerical Rating Scale (NRS), with 0 representing no pain and 10 representing the worst possible pain.

  Week 12

Secondary Outcomes (30)

• At least a 50% reduction from baseline to Week 12 in pain intensity.

  Week 12

• Change from baseline in CRPS Severity Score (CSS) to Week 12.

  Week 12

• Patient Global Impression of Change (PGI-C) in CRPS-Related Health.

  Week 12

• Change from baseline in the Short Form 36 (SF-36) Item Health Survey Physical Functioning domain.

  Week 12

• Change from baseline over time in pain intensity.

  Day 10, Weeks 3, 6, and 9

Study Arms (2)

neridronate

EXPERIMENTAL

400 mg AMBTX-01 infusion

Drug: Neridronate

Placebo

PLACEBO COMPARATOR

Placebo comparator

Drug: Placebo

Interventions

Neridronate DRUG

neridronate 100 mg, given as a 2-hour infusion on Days 1, 4, 7, and 10.

neridronate

Placebo DRUG

placebo comparator

Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female participant ≥ 18 years of age at time of Screening.
• A diagnosis of CRPS-1 according to the clinical Budapest Criteria as recommended by the International Association for the Study of Pain (IASP), as well as no known peripheral nerve injury. Signs and symptoms of CRPS must apply to a single identified affected limb (i.e., arm, hand, wrist, leg, ankle or foot) and must demonstrate asymmetry with respect to the contralateral limb.
• Single affected limb at the Screening and Randomization Visits meeting the following warm subtype criteria:
• Edema in the affected limb
• AND ≥ 2 of the following:
• Obvious redness in the affected region relative to the same region on the contralateral limb on inspection
• ≥ 1°C increase in temperature on the affected limb relative to the contralateral limb
• Moderate-to-severe edema
• CRPS symptoms ≤ 6 months since onset.
• Increased uptake in the involved limb compared to the contralateral limb on TPBS (phase 2 and/or phase 3) during Screening. A historic scan not older than 3 months prior to Randomization Visit is acceptable, if available and of sufficient quality for a central read.
• "Pain now" assessments of \> 4 on the 11 point numerical rating scale in the CRPS affected limb.
• Women of childbearing potential must:
• Be nonpregnant.
• Be nonlactating.
• Agree to use a highly effective method of contraception and for at least 6 months following last investigational product administration.

You may not qualify if:

• A current or prior diagnosis of CRPS Type 2 or CRPS not otherwise specified (CRPS NOS), or whose CRPS has no known inciting event, or CRPS-1 without criteria of the warm subtype at the time of Screening.
• ≥ 40 points on the Pain Catastrophizing Scale.
• Prior use of neridronate or participation in a clinical study where the participant may have received neridronate.
• Participants currently taking or planning to be treated with prohibited concomitant medications/therapies, or not likely able to follow the protocol restrictions for use of concomitant treatment.
• Severely impaired renal function.
• Hypocalcemia.
• Vitamin D deficiency.
• Significant dental findings such as an unhealed tooth extraction site.
• Eye inflammation.
• Significantly elevated liver-related lab tests or evidence of significant liver disease.
• Clinically unstable cardiac disease.
• Any known conditions, from 3 months prior to Screening Visit or to the Randomization Visit, that may interfere with the assessment of CRPS-1, CRPS-related pain, safety, or other trial assessments.

Sponsors & Collaborators

• Ambros Therapeutics, Inc.: lead

Study Sites (6)

Ambros Clinical Trial Site

Phoenix, Arizona, 85032, United States

RECRUITING

Ambros Clinical Trial Site

Tucson, Arizona, 85710, United States

RECRUITING

Ambros Clinical Trial Site

Tustin, California, 92780, United States

RECRUITING

Ambros Clinical Trial Site

Pembroke Pines, Florida, 33025, United States

RECRUITING

Ambros Clinical Trial Site

Newnan, Georgia, 30265, United States

RECRUITING

Ambros Clinical Trial Site

Winston-Salem, North Carolina, 27103, United States

RECRUITING

MeSH Terms

Conditions

Complex Regional Pain Syndromes; Edema; Pain

Interventions

6-amino-1-hydroxyhexane-1,1-diphosphonate

Condition Hierarchy (Ancestors)

Autonomic Nervous System Diseases; Nervous System Diseases; Peripheral Nervous System Diseases; Neuromuscular Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Neurologic Manifestations

Central Study Contacts

SVP, Clinical Operations

CONTACT

+1 949-785-4954; clinicaltrials@ambrostx.com

Ambros Therapeutics, Inc

CONTACT

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 17, 2025
• First Posted: October 7, 2025
• Study Start: April 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): January 1, 2028
• Last Updated: April 27, 2026

Record last verified: 2026-04

Locations

US (6)