Evaluating Intra-articular Injection of Axolotl Ambient Compared to Saline in Subjects With Ankle Osteoarthritis (Phoenix)

  • End date
    Dec 1, 2024
  • participants needed
  • sponsor
    Axolotl Biologix
Updated on 30 June 2022
Accepts healthy volunteers


A Double-blind, Multi-Center, Prospective, Randomized Placebo-controlled Pilot Study Evaluating Intra-articular Injection of Axolotl Ambient Compared to Saline in Subjects with Ankle Osteoarthritis. The goal of this pilot study and subsequent pivotal trial is to evaluate the safety and effectiveness of Axolotl Ambient intra-articular injection for ameliorating the pain and dysfunction associated with ankle OA.


This pilot study is a double-blind multi-center, prospective, randomized, placebo-controlled trial. Upon randomization, patients will receive 1 intraarticular injection of the investigational product or control fluid. Follow-up will be conducted at 4 weeks, 3 and 6 months, with 6 months serving as the primary endpoint. The primary outcomes will consist of patient reported outcomes of pain and functional assessment by the physician, specific to the foot and ankle. Subjects will be monitored for an additional 6 months to establish safety over a 1-year follow-up and evaluate the durability of benefit.

Condition Ankle Osteoarthritis
Treatment Axolotl Ambient, "Drug/Placebo: 0.9% Normal Saline"
Clinical Study IdentifierNCT05092646
SponsorAxolotl Biologix
Last Modified on30 June 2022


Yes No Not Sure

Inclusion Criteria

Signed written informed consent
Willing to be randomized to either the investigational or control group
Male or female at least 18 years of age and less than 80
Clinical diagnosis of symptomatic tibiotalar (ankle) OA (primary idiopathic OA or post-traumatic OA), modified K-L grade 1-3a
One ankle is the most symptomatic lower extremity joint and the only lower extremity joint currently planned for treatment
Willing and able to comply with all study requirements including all postoperative clinical and radiographic evaluations
For women of childbearing potential (not post-menopausal for 12 months or surgically sterile), a urine pregnancy test with a negative result must be obtained at screening and on the day of procedure, prior to injection
Male and female trial participants must commit to adequate birth control (e.g., surgically sterilized, oral contraceptive, two methods of barrier birth control, or abstinence) through the final follow-up
Chronic ankle pain for ≥ 6 months
SAOS Pain score ≥ 30 and ≤ 80 and AOS Function score ≥ 30 and ≤ 80
Willing to discontinue all prescription and over-the-counter pain medications being used for ankle OA symptoms for the duration of the study, except for acetaminophen, which is not allowed for the 3 days preceding each scheduled follow-up visit and the day of the follow-up visit

Exclusion Criteria

Previously received intra-articular injections in the index joint of Axolotl Ambient, bone marrow aspirate concentrate (BMAC), platelet-rich plasma (PRP), or other biologic-based products within the last 12 months
Modified K-L Grade 3b or 4 osteoarthritis of the index joint
Diagnosis of ipsilateral peri-articular arthritis (e.g. subtalar joint) that the investigator determines may significantly confound the study results
Received intra-articular hyaluronic acid injection in the index joint within the last 6 months
Received intra-articular steroid injection in the index joint within the last 3 months
Prior major surgical repair or reconstruction of the ankle that the investigator determines may significantly confound the study results
Baseline pain catastrophizing score ≥ 23
Any surgery of the index ankle within the last 12 months
Planned arthroscopy or other procedure on the ankle during the study
Bilateral ankle OA requiring treatment of both ankles
Pregnancy, breastfeeding, or woman of child-bearing potential not using adequate contraception
Bone deficit
Charcot foot disease
Radiographic evidence of open epiphyses
Systemic inflammatory condition
Substantial vascular insufficiency
Current treatment with anticoagulants
Deformity in coronal, axial or sagittal plane greater the 30°
Patients weighing less than 47 kg
BMI greater than 45 kg/m2
Documented medical history of, or radiographic evidence of, a bone disease (e.g. severe osteoporosis or avascular necrosis) or other condition (e.g., osteolysis)
Comorbidity that would limit the ability to administer any functional measurements
Has at the time of injection, a systemic or local infection at the site of injection
Medical condition, serious intercurrent illness, or extenuating circumstance that, in the opinion of the Investigator, would preclude participation in the study or potentially decrease survival or interfere with ambulation or rehabilitation (e.g., history of transient ischemic attack, stroke or liver disease)
Known hypersensitivity to penicillin
Known allergy to phenol red
Currently receiving treatment with a drug known to interfere with bone or cartilage metabolism [e.g., systemic steroid therapy (topical steroid therapy is permissible), methotrexate]
Medical condition requiring radiation, chemotherapy or immunosuppression
Have an active history of malignancy (except for basal cell carcinoma of the skin)
Has a history of autoimmune disease known to affect bone or cartilage. Examples include spondyloarthropathies (e.g., ankylosing spondylitis, Crohn's disease, and ulcerative colitis), Juvenile Arthritis, rheumatoid arthritis, Grave's disease, and Hashimoto's thyroiditis
Has obvious or documented alcohol or illicit drug addictions
Is a prisoner in a correctional institution/facility
Actively involved in litigation or workman's compensation
Has participated in clinical studies evaluating investigational devices, pharmaceuticals or biologics within 6 months of randomization
Bedridden, confined to a wheelchair, or unable to walk 50 m without the help of a walker, crutches, or cane
Is currently taking prescription pain medication for any conditions other than ankle osteoarthritis
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