Clinical trial Recruiting at 12 sites Phase 3 Interventional Ages 17 to 65

MACI versus bone marrow stimulation for symptomatic ankle cartilage defects in people 17–65

Official title: A Prospective, Open-label, Randomized, Concurrent Active-controlled, Longitudinal, Multicenter, Phase 3 Clinical Study of the Safety and Efficacy of MACI in Patients With Symptomatic Chondral or Osteochondral Lesions of the Talus (MASCOT)

Run by Vericel Corporation · NCT06915233 · Data updated 2026-11-12

This treatment comparison tests whether MACI (your own cultured cartilage cells on a collagen membrane) works better than bone marrow stimulation for people aged 17 to 65 with symptomatic cartilage defects of the talus.

Quick facts

PhasePhase 3
Study typeInterventional
Ages17 Years to 65 Years
SexAll
Enrollment309 (estimated)
SponsorVericel Corporation
Industry-sponsored
Locations12 sites (Gilbert, Arizona and 11 other locations)
StatusRecruiting
StartedMay 28, 2026
Main results expectedJuly 2030
Study endsJuly 2030
Registry record updatedNovember 5, 2026
Trial IDNCT06915233 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are people aged 17–65 with symptomatic ICRS grade 3–4 chondral or osteochondral lesions on the talus, at least one lesion ≥1.2 cm², FAOS pain and function scores ≤50, and who are suitable for surgical treatment and follow-up.

Probably not a fit

Patients unlikely to benefit include those with lesions smaller than 1.2 cm², lesions outside the talus, advanced degenerative joint disease, inability to undergo surgery or follow postoperative restrictions (including NSAID limitations), or those outside the 17–65 age range.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a 2-year, prospective, multicenter, open-label Phase 3 randomized trial enrolling 309 participants aged 17–65 with symptomatic talar chondral or osteochondral lesions of at least 1.2 cm². After screening and an index ankle arthroscopy to confirm lesion size and eligibility, subjects undergo a cartilage biopsy and are randomized 2:1 to receive a one-time MACI implantation or arthroscopic bone marrow stimulation (BMS). MACI products are manufactured from the participant's biopsy at the Vericel facility and implanted on a porcine collagen membrane, while the BMS arm receives marrow stimulation during the same arthroscopy. Participants follow a standardized postoperative rehabilitation program and are followed for outcomes over two years.

Why it matters

Potential benefit: If successful, MACI could provide more durable cartilage repair in the ankle, reducing pain and improving function compared with standard bone marrow stimulation.

How similar studies have gone: MACI and other autologous chondrocyte implantation techniques have shown positive results in the knee and smaller ankle series, but large randomized comparisons specifically in the ankle remain limited.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Age 17 to 65 at the time of planned randomization visit (Visit 2).
2. One or more symptomatic chondral or osteochondral lesion/s as defined by FAOS Pain score ≤ 50 and FAOS Function (SRA) score ≤ 50.
3. International Cartilage Repair Society (ICRS) Score Grade 3 or 4 chondral or osteochondral lesion/s located on the talus with or without cysts, including shoulder lesions (lesions on the talar neck), and amenable to treatment with the surgical procedure specified at randomization.
4. At least 1 lesion ≥ 1.2 cm².
5. Written informed consent and assent (as applicable) per Institutional Review Board (IRB) requirements.
6. Participant will refrain from using Non-steroidal Anti-inflammatory Drugs (NSAIDS) for 12 weeks post-study treatment. (Post-surgical use of low-dose aspirin for clot prevention is acceptable).
7. Participant will restrict pain medication to over-the-counter analgesics (NSAIDs or acetaminophen/paracetamol) after 12 weeks post-study treatment.
8. Participant must have Hematocrit ≥30.0%; White Blood Cell count ≤14,000 cells/μL; Platelet Count ≥50,000 platelets/μL; Creatinine ≤2.0 mg/dL; and International Normalized Ratio (INR) ≤1.6.

Exclusion Criteria:

1. Lesions with an underlying bony defect depth of \> 5 mm.
2. Any surgery on the target joint within 24 weeks prior to Visit 1 (not including diagnostic ankle arthroscopy).
3. Previous investigational drug, biologic or device use within 12 weeks prior to Visit.
4. Avascular necrosis of the target ankle.
5. Symptomatic musculoskeletal conditions in the lower limbs that could impede measurement of efficacy for the target ankle joint.
6. Participant with "kissing lesions" (bipolar lesions, involving both the tibia and talus), or with bilateral lesions in both ankles.
7. Participant with lesions that require an osteotomy procedure to allow for MACI implantation as determined at the time of ankle arthroscopy (Visit 2).
8. Concomitant systemic inflammatory diseases or other conditions that affect the joints (e.g., rheumatoid arthritis, metabolic bone disease, psoriasis, symptomatic chondrocalcinosis).
9. History of advanced or severe osteoarthritis of the ankle as determined by prior surgical history confirming no joint space (i.e., "bone on bone") or radiographic evidence of Modified Kellgren-Lawrence Grade 4 arthritis (i.e., osteophytes on lateral and medial malleoli and at the tibiotalar joint margins, narrowing of the joint space width \> 50%, and tibiotalar sclerosis), Van Dijk Grade III (i.e., total or subtotal destruction of the joint space) or the equivalent.
10. Known history of septic arthritis in the target ankle joint within 1 year prior to Visit 1.
11. Current malignancy or treatment for malignancy within the past 5 years prior to Visit 1, excluding non-melanoma skin cancer.
12. Known history of hypersensitivity to gentamicin, other aminoglycosides, or products of porcine or bovine origin.
13. Females who are pregnant or lactating.
14. Patients who, in the opinion of the Investigator, have significant medical or psychosocial problems that warrant exclusion. Examples of significant problems included but are not limited to:

    1. Any condition that has potential for negatively impacting intra- or postoperative course (e.g., uncontrolled diabetes, heavy smoking). - Uncontrolled diabetes is defined as hemoglobin A1c (HbA1c) ≥8.0% and/or fasting plasma glucose \>250 mg/dL (13.9 mmol/L) within the last 90 days prior to Screening Visit 1 - Heavy smoking is defined as current smoker with use of ≥20 cigarettes per day (≥1 pack/day) at the time of Screening Visit 1.
    2. Conditions that limit compliance with rehabilitation program.
    3. Any condition that has potential for significantly limiting participant's ability to assess postoperative ankle function.
    4. Any condition, psychiatric or otherwise, that would preclude informed consent/assent, consistent follow-up, or compliance with any aspect of the clinical trial.
    5. Participant is currently abusing drugs or alcohol or, in the opinion of the Investigator, at high risk for poor compliance.
    6. Any abnormal screening blood work that the Investigator deems clinically significant in addition to the parameters delineated in Inclusion Criterion #8.
15. Injection of hyaluronic acid (HA), platelet-rich plasma (PRP), and/or corticosteroids in the target ankle within 90 days prior to Visit 1.

Where it's running

  • Orthopedic Specialists of North America, PLLC d/b/a OrthoArizona - South Gilbert
    Gilbert, Arizona, United States
    Recruiting
  • Castro Valley Care Center
    Castro Valley, California, United States
    Recruiting
  • UC Davis Foot and Ankle Clinic
    Sacramento, California, United States
    Recruiting
  • The Steadman Clinic
    Vail, Colorado, United States
    Recruiting
  • MedStar Georgetown University Hospital
    Washington D.C., District of Columbia, United States
    Recruiting
  • Elevate Clinical Research Wichita
    Wichita, Kansas, United States
    Recruiting
Show 6 more locations
  • Mayo Clinic
    Rochester, Minnesota, United States
    Recruiting
  • Duke Orthopaedic Surgery
    Durham, North Carolina, United States
    Recruiting
  • University of Pittsburgh Medical Center Freddie Fu Sports Medicine Center
    Pittsburgh, Pennsylvania, United States
    Recruiting
  • Elevate Clinical Research
    Houston, Texas, United States
    Recruiting
  • Rodaro, LLC
    San Antonio, Texas, United States
    Recruiting
  • UVA Orthopedic Center Ivy Road
    Charlottesville, Virginia, United States
    Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

  • Using autologous chondrocyte suspension for knee cartilage repair

    This study is testing whether using a patient’s own cartilage cells can help repair knee cartilage damage and improve their knee function over a year.

    Recruiting Centre Hospitalier Universitaire Vaudois · Lausanne, Canton of Vaud · NCT04296487

  • Comparing MACI and microfracture treatments for knee cartilage defects in teens

    This study is testing whether a new cartilage treatment called MACI works better than a standard procedure called microfracture for knee problems in teens aged 10 to 17.

    Recruiting at 12 sites Phase 3 Vericel Corporation · Palo Alto, California and 14 other locations · NCT03588975

  • Evaluating the outcomes of cartilage repair surgery in the knee

    This study is testing how well cartilage repair surgery helps people with knee injuries feel and move better after the operation.

    Recruiting at 4 sites University of Manchester · Birmingham and 6 other locations · NCT06921889

  • Effects of PRP, PPP, and BMAC on recovery after hip surgery for labral issues

    This study is testing whether treatments like platelet-rich plasma and bone marrow concentrate can help people recover better after hip surgery for labral issues.

    Recruiting Phase 3 Massachusetts General Hospital · Boston, Massachusetts · NCT06003101

  • Using rib cartilage to treat ankle joint lesions

    This study is testing whether using rib cartilage to treat ankle joint damage can help people recover better and have fewer side effects than a different treatment.

    Recruiting The Third Affiliated Hospital of Southern Medical University · Guangzhou, Guangdong · NCT05942430

  • Comparing AMIC and microfracture for hip cartilage damage

    This study is testing whether a new treatment called AMIC works better than microfracture for helping people with hip cartilage damage feel better and improve their quality of life after surgery.

    Recruiting Phase 1 McMaster University · Hamilton, Ontario · NCT05402072

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.