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Study on the Effects of RHH646 for Patients with Knee Osteoarthritis

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying knee osteoarthritis, a common joint condition that causes pain and stiffness in the knee. The study will test a new treatment called RHH646, which is taken as a hard capsule by mouth. The purpose of the study is to evaluate the ability of RHH646 to help regenerate the cartilage in the knee over a period of one year, as well as to assess its safety and how well it is tolerated by participants.

Participants in the study will be randomly assigned to receive either the RHH646 capsules or a placebo, which looks like the RHH646 capsules but does not contain the active ingredient. The study is designed so that neither the participants nor the researchers know who is receiving the actual treatment or the placebo, ensuring unbiased results. Over the course of the study, participants will have regular check-ups and tests, including MRI scans, to monitor changes in their knee cartilage and overall health.

The study will last for a total of 52 weeks, during which participants will take the capsules daily. The researchers will collect information on any side effects, changes in vital signs, and results from blood and urine tests to ensure the safety of the treatment. This trial aims to provide valuable insights into the potential benefits of RHH646 for people with knee osteoarthritis.

The research process

The trial runs in 2 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    <b>treatment administration</b>

    You will take either a test medication called rhh646 or a placebo, which is an inactive substance that looks like the medication but contains no active ingredients.

    If assigned the test medication, you will take 75 mg of rhh646 in the form of a hard capsule by oral use (swallowing it).

    The treatment duration lasts for one year.

  2. Step 2

    <b>medical assessments</b>

    During the one-year period, several medical evaluations are performed to monitor safety and how the body responds to the substance.

    An mri (magnetic resonance imaging, a type of detailed scan) is conducted at week 52 to measure changes in the cartilage volume (the protective tissue in the knee joint).

    Regular checks include vital signs (such as blood pressure), ecg (an electrocardiogram to check heart activity), hematology (blood tests), blood chemistry (tests to check organ function), and urinalysis (testing urine).

    At week 4, measurements are taken to determine plasma concentrations, which refers to the amount of the medication present in the bloodstream.

Who can join the trial?

7 criteria

  • You must be between 35 and 75 years old at the time of your initial evaluation.
  • You must weigh at least 50 kg (about 110 pounds) and have a body mass index (BMI) of 35 or less. BMI is a measure of your body weight relative to your height.
  • You must have been diagnosed with tibiofemoral osteoarthritis in at least one knee. This is a type of wear-and-tear in the main joint of the knee.
  • Your knee X-ray must show K&L grade 2 or 3 osteoarthritis. The K&L grade is a scale used by doctors to measure how much damage is visible on an X-ray.
  • The damage must be mostly in the medial compartment of the knee. This means the inner side of the knee joint shows more joint space narrowing (a sign that the protective cartilage is thinning) than the outer side.
  • You must have symptoms, meaning you have experienced knee pain at least 3 days per week during the last 3 months.
  • Your knee pain must be able to be eased by analgesic therapy. An analgesic is a type of medicine used to relieve pain, such as acetaminophen (APAP) or non-steroidal anti-inflammatory drugs (NSAIDs).

Who cannot join the trial?

11 criteria

  • Women who are able to become pregnant.
  • People who cannot have an MRI, which is a medical imaging test that uses magnets to take pictures of the inside of the body, due to fear of enclosed spaces, body size, or having metal objects in the body like pacemakers (devices that control heart rhythm) or defibrillators (devices that restore normal heart rhythm).
  • People who have had arthroscopy, a surgery where a doctor looks inside a joint using a small camera, in the knee being studied within the last 6 months or who plan to have this surgery during the study.
  • People who have had specific previous surgeries on the knee being studied, such as mosaicplasty (a procedure to replace damaged cartilage), microfracture (a procedure to stimulate bone marrow to heal cartilage), meniscectomy (removal of part of the meniscus, which is the cushion in the knee), or osteotomy (a surgery to reshape the bone).
  • People who have an unstable knee joint or ligaments, which are tissues that connect bones, that were not repaired well enough.
  • People with severe malalignment, meaning the leg is not straight, specifically a valgus deformity (knock-knees) or varus deformity (bow-leggedness) greater than 7.5 degrees as seen on an X-ray.
  • People with K&L grade 4 OA, which is the most advanced stage of osteoarthritis, a condition where the protective cartilage in the joints wears down.
  • People with severe osteoarthritis in the hip that changes how they walk or affects the pressure on the knee, or hip issues that will require medical or surgical treatment during the study.
  • People with other knee problems, such as subchondral insufficiency fractures (small cracks in the bone just below the cartilage), bone fractures, bone bruises, osteonecrosis (bone tissue death due to lack of blood supply), bone tumors, or patellofemoral dysplasia (improper development of the kneecap area).
  • People with autoimmune diseases, which are conditions where the immune system mistakenly attacks the body, such as inflammatory arthritis, gout (a type of painful joint swelling caused by crystals), Lyme disease, or fibromyalgia (a condition causing widespread pain).
  • People with active infections in the knee joint or known connective tissue diseases, which are disorders affecting the tissues that support the body.
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Investigated drugs

RHH646 is an experimental medicine taken by mouth in capsule form. This study is testing if this treatment can help regrow the cartilage in the knee joint for people living with knee osteoarthritis.

What is already known about the treatment

  • Placebo

    This is an inactive substance presented in hard capsules that is taken by mouth. It is used in clinical studies as a control to compare against the active treatment to ensure the results are accurate. It has no therapeutic purpose and does not work on any specific biological process in the body.

  • RHH646

    This medication is administered as a hard capsule that is swallowed by mouth. It is currently being studied in clinical trials to determine its effectiveness and safety for treating knee osteoarthritis. This substance is designed to work at a cellular level to help the body regrow and repair the protective cartilage in knee joints. It is classified as a potential cartilage-regenerating agent aimed at improving musculoskeletal health.

Investigated diseases

Knee Osteoarthritis - This condition involves the gradual breakdown of the protective cartilage that cushions the ends of the bones in the knee joint. As the cartilage wears away over time, the bones may begin to rub against each other. This process can lead to swelling and changes in the structure of the joint. The condition typically progresses slowly as the cushioning material continues to thin.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2022-502821-16-00Protocol codeCRHH646A12201Estimated enrolment88 patientsSponsorNovartis Pharma AG

sourced from the EU Clinical Trials Register and site verification

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