Open-label Trial to Check the Safety and Tolerability of RTX-GRT7039 Injections for Pain Associated With Osteoarthritis of the Knee

Phase 3

Completed

• Conditions: Osteoarthritis
• Interventions: Drug: RTX-GRT7039

• Registration Number: NCT05377489
• Lead Sponsor: Grünenthal GmbH

Brief Summary

An open-label, single-arm clinical trial to confirm the safety of monoarticular injections or bi-lateral intra-articular injections of RTX-GRT7039 in patients who have pain associated with osteoarthritis of the knee despite standard of care.

Detailed Description

This trial comprises a total observation period of up to 78 weeks.

Study Timeline

• Study First Submitted: 2022-05-12
• Study First Submitted QC: 2022-05-12
• Study First Posted: 2022-05-17
• Study Start: 2022-09-15
• Primary Completion: 2025-05-15
• Study Completion: 2025-05-15
• Status Verified: 2025-07
• Last Update Submitted: 2025-07-22
• Last Update Posted: 2025-07-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 750

Inclusion Criteria

• The participant has given written informed consent to participate.
• The participant is 18 years of age or older at the Screening Visit.
• The participant has a diagnosis of osteoarthritis of the knee based on American College of Rheumatology criteria and functional capacity class of I to III.
• There is a documented history indicating that participant has insufficient pain relief with previous Standard of Care.

Exclusion Criteria

• The participant has past joint replacement surgery of the index knee.
• The participant has a history of significant trauma or surgery (e.g., open or arthroscopic) to the index knee within 12 months of Screening.
• The participant has periarticular pain at the index knee from any cause other than osteoarthritis, including referred pain, bursitis, tendonitis.
• The participant has clinical hip osteoarthritis on the side of the index knee.
• The participant has a history of osteonecrosis, subchondral insufficiency fracture, atrophic osteoarthritis, rapidly progressing osteoarthritis (RPOA) Type I or Type II,pathologic fracture, primary or metastatic tumor, or joint infection in the index knee.
• The participant has significant malalignment of anatomical axis (medial angle formed by the femur and tibia) of the target knee (varus >10°, valgus >10°) by radiograph as assessed by independent Central Readers at Screening Visit.
• The participant has other conditions that could affect trial endpoint assessments of the index knee.
• The participant has current clinically significant disease(s) or condition(s) that may affect safety assessments, or any other reason which may preclude the participant's participation for the full duration of the trial.
• The participant has a history of hypersensitivity to resiniferatoxin (RTX) or any similar component (capsaicin, chili peppers).
• The participant is currently participating or was participating in another investigational drug trial within 3 months prior to the Screening Visit.
• The participant is an employee of the investigator or trial site, with direct involvement in the proposed trial or other trials under the direction of that investigator or trial site or is a family member of the employees or the investigator.

The non-index knee is not eligible for treatment in the trial, if any of the knee-related exclusion criteria applies to the non-index knee.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
RTX-GRT7039	RTX-GRT7039	Participants will receive injections of RTX-GRT7039 into either the index knee (affected knee or in case of bilateral OA the knee with highest pain intensity), or each of both knees up to Week 52.

Primary Outcome Measures

Name	Time	Method
Number of Participants With Treatment Emergent Adverse Events (TEAEs)	From Baseline up to Week 78

Secondary Outcome Measures

Name	Time	Method
Change from Baseline in WOMAC A1 (Walking Pain) Score	From Baseline up to Week 12	The WOMAC A1 score will be assessed using an 11-point NRS, where 0= no pain and 10=worst pain.
Percentage of Participants With at Least 30%, 50% and 70% Reduction From Baseline in WOMAC Pain Subscale Score	From Baseline up to Week 12	The WOMAC pain subscale will be assessed using an 11-point NRS, where 0= no pain and 10=worst pain.
Percentage of Participants With at Least 30%, 50% and 70% Reduction From Baseline in WOMAC A1 (Walking Pain) Score	From Baseline up to Week 12	The WOMAC A1 score will be assessed using an 11-point NRS, where 0= no pain and 10=worst pain.
Number of Participants With Treatment Emergent Adverse Events (TEAEs) Representing Structural Changes as Assessed by Imaging Methods	From Baseline up to Week 78
Change from Baseline in WOMAC Pain Subscale Score	From Baseline up to Week 12	The WOMAC pain subscale will be assessed using an 11-point numerical rating scale (NRS), where 0= no pain and 10=worst pain.
Change from Baseline in WOMAC Stiffness Subscale Score	From Baseline up to Week 12	The WOMAC stiffness subscale will be assessed using an 11-point NRS, where 0= no stiffness and 10= extreme stiffness.
Change from Baseline in WOMAC Total Score	From Baseline up to Week 12	The WOMAC total score will be calculated as the sum of pain subscale score, stiffness subscale score and physical function subscale score. It will be calculated by averaging all of the scores available for the questions and assessed using an 11-point NRS, where 0=best outcome and 10=worst outcome.
Percentage of Participants Categorized by Each Patient Global Impression of Change (PGIC) Score	From Baseline up to Week 12	The 7-point PGIC is a complementary assessment of analgesic efficacy on a 7-point scale where 1 = "Very much improved" and 7 = "Very much worse".
Change from Baseline in WOMAC Physical Function Subscale Score	From Baseline up to Week 12	The WOMAC physical function subscale will be assessed using 11-point NRS, where 0= no difficulty and 10=extreme difficulty.
Change From Baseline in EuroQol-5 Dimension Health Questionnaire 5 Levels (EQ-5D-5L) Score	From Baseline up to Week 12	EQ-5D consists of EQ-5D descriptive system (Index score) and EQ visual analogue scale (VAS). EQ-5D-5L Index Score ranges from 0 to 1, with 0 representing death and 1 representing perfect health. EQ-5D-5L-VAS records participant's self-rated health on a vertical VAS that range from 0 (worst imaginable) to 100 (best imaginable).
Change From Baseline in Patient-Specific Functional Scale (PSFS)	From Baseline up to Week 12	The PSFS scale will be assessed using an 11-point NRS, where 0= Unable to perform activity and 10=Able to perform activity at the same level as before your osteoarthritis of the knee started.
Change From Baseline in 36-Item Short-Form (SF-36) Domain Scores	From Baseline up to Week 12	The 8 SF-36 domain scores range from 0 (worst value) to 100 (best value), with higher scores reflecting better health status.

Trial Locations

Locations (91)

Arizona Arthritis and Rheumatology Associates (AARA) P.C; 🇺🇸 Glendale, Arizona, United States

Elite Clinical Studies, LLC; 🇺🇸 Phoenix, Arizona, United States

Orange County Research Institute; 🇺🇸 Anaheim, California, United States

Acclaim Clinical Research, Inc.; 🇺🇸 San Diego, California, United States

Westlake Medical Research; 🇺🇸 Thousand Oaks, California, United States

Progressive Medical Research; 🇺🇸 Port Orange, Florida, United States

Gulfcoast Research Institute; 🇺🇸 Sarasota, Florida, United States

Palm Beach Research Center; 🇺🇸 West Palm Beach, Florida, United States

North Georgia Clinical Research; 🇺🇸 Woodstock, Georgia, United States

Injury Care Research; 🇺🇸 Boise, Idaho, United States

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