Efficacy and Safety of GNSC-001 Intra-articular Injection for Knee Osteoarthritis

The goal of this clinical trial is to learn if GNSC-001 works to treat knee osteoarthritis in adults. It will also learn about the safety of GNSC-001. The main questions it aims to answer are:

1. Does GNSC-001 lower daily knee joint pain and improve function in participants? 2. What medical problems do participants have when taking GNSC-001?

Researchers will compare GNSC-001 to a placebo (a look-alike substance that contains no drug) to see if GNSC-001 works to treat knee osteoarthritis.

Participants will:

1. Receive a single injection of immune-modulation, and GNSC-001 or a placebo, in their knee 2. Take an oral immune-modulating pill every day for the first 22 days 3. Visit the clinic at least 9 times over 2 years for checkups and tests 4. Keep a diary of their symptoms and the number of times they use a rescue medication

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Key information

Conditions

Knee Arthritis Osteoarthritis Arthritis Joint Diseases Knee Arthritis Knee Arthritis Disease Knee Arthritis, Osteoarthritis Musculoskeletal Diseases Neurologic Manifestations Osteo Arthritis Knee Osteo Arthritis of the Knee Osteoarthritic Knee Pain Osteoarthritis Osteoarthritis (OA) of the Knee Pain Pain (Knee) Pathological Conditions, Signs and Symptoms Rheumatic Diseases Signs and Symptoms

Age range

40 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2 / Phase 3

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

OA in the target knee confirmed by radiograph and with a Kellgren-Lawrence (KL) score of 2 or 3
OA symptoms affecting the target knee present for at least 6 months
NRS pain score 5-9 (0-10 scale) in the target knee within the 24 hours prior to the time of consent
Synovitis and/or effusion detectable on imaging
Willing to stop use of any medication taken for knee OA pain for the duration of the study, including but not limited to nonsteroidal anti-inflammatory drugs (NSAIDs)
Able to provide written informed consent and comply with the requirements of the study

Key Exclusion Criteria:

Body mass index (BMI) > 38 kg/m2
NRS pain score in other (non-target) knee ≥ 4
Large effusion, substantial malalignment, structural compromise, prior partial or total joint replacement of target knee
Surgery on the target knee within the 6 months prior to screening or the anticipated need for treatment of either knee prior to the Month 12 Visit.
Current or history of inflammatory conditions (e.g., gout or rheumatoid arthritis), other joint disorders, septic arthritis, nerve damage or injury, chronic pain not associated with knee OA (e.g., fibromyalgia, hip OA), or otherwise immunocompromised
Active infection
Uncontrolled diabetes mellitus, glycosylated hemoglobin (HbA1c) >7.0% at screening
Initiation of GLP-1RA, or similar medication, within the last 12 months, or discontinued within last 6 months prior to Screening
Use of opioid medications (including tramadol or tapentadol) or medical/recreational cannabinoids (oral/inhaled) for > 5 days within the last 30 days
Use of medications for the treatment of chronic pain, immunosuppressant medications, or intra-articular injections into the target knee within 90 days of Day 1
Current use of anticoagulant therapy
Received live vaccine within 6 weeks of Day 1
Participation in another interventional clinical study with experimental therapy within 90 days prior to screening
Relies on a walking aids (e.g., cane, crutch, walker, wheelchair) or a personal assistant
Pregnant, breastfeeding, or intending to become pregnant during the study

Treatment and study plan

Gene Therapy GNSC-001

Drug

Single intra-articular injection into target knee

Placebo

Drug

Single intra-articular injection into target knee

Primary outcomes

Change from baseline in OA pain as assessed by the Weekly Average of Daily Pain (WADP) Numeric Rating Scale (NRS) at Week 52

Time frame: Baseline and Week 52
Change from baseline in the function subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at Week 52

Time frame: Baseline and Week 52
Incidence and severity of treatment emergent adverse events (TEAEs), events of clinical interest (ECIs), and serious adverse events (SAEs)

Time frame: From enrollment to the end of study at 104 weeks

Study contacts

Contact information is provided by the study sponsor or research team.

Head of Clinical Development

CONTACT

[email protected]

408-475-8627

Sponsors and collaborators

Lead sponsor

Genascence Corporation

Industry

Registry information

Official study title

A Randomized, Double-blind, Placebo-controlled, Phase 2/3, Study to Evaluate the Efficacy and Safety of an Intraarticular Injection of GNSC-001 in Participants With Osteoarthritis of the Knee

Acronym: RAPHAEL

Important dates

Study start: 2027
Primary completion: 2029
Study completion: 2030
First posted: Sep 21, 2026
Registry last updated: Sep 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Recruiting