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

August 5, 2026 updated by: Axolotl Biologix

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

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Idaho
      • Boise, Idaho, United States, 83713
        • Injury Care Research
    • Louisiana
      • Shreveport, Louisiana, United States, 71101
        • Orthopedic Specialists of Louisiana
    • North Carolina
      • Charlotte, North Carolina, United States, 28207
        • OrthoCarolina Foot and Ankle Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 76 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Signed written informed consent
  2. Willing to be randomized to either the investigational or control group
  3. Male or female at least 18 years of age and less than 80
  4. Clinical diagnosis of symptomatic tibiotalar (ankle) OA (primary idiopathic OA or post-traumatic OA), modified K-L grade 1-3a
  5. One ankle is the most symptomatic lower extremity joint and the only lower extremity joint currently planned for treatment
  6. Willing and able to comply with all study requirements including all postoperative clinical and radiographic evaluations
  7. 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
  8. 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
  9. Chronic ankle pain for ≥ 6 months
  10. SAOS Pain score ≥ 30 and ≤ 80 and AOS Function score ≥ 30 and ≤ 80
  11. 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:

  1. 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.
  2. Modified K-L Grade 3b or 4 osteoarthritis of the index joint
  3. Diagnosis of ipsilateral peri-articular arthritis (e.g. subtalar joint) that the investigator determines may significantly confound the study results
  4. Received intra-articular hyaluronic acid injection in the index joint within the last 6 months
  5. Received intra-articular steroid injection in the index joint within the last 3 months
  6. Prior major surgical repair or reconstruction of the ankle that the investigator determines may significantly confound the study results
  7. Baseline pain catastrophizing score ≥ 23
  8. Any surgery of the index ankle within the last 12 months
  9. Planned arthroscopy or other procedure on the ankle during the study
  10. Bilateral ankle OA requiring treatment of both ankles
  11. Pregnancy, breastfeeding, or woman of child-bearing potential not using adequate contraception
  12. Bone deficit
  13. Charcot foot disease
  14. Radiographic evidence of open epiphyses
  15. Systemic inflammatory condition
  16. Substantial vascular insufficiency
  17. Current treatment with anticoagulants
  18. Deformity in coronal, axial or sagittal plane greater the 30°
  19. Patients weighing less than 47 kg.
  20. BMI greater than 45 kg/m2
  21. Documented medical history of, or radiographic evidence of, a bone disease (e.g. severe osteoporosis or avascular necrosis) or other condition (e.g., osteolysis)
  22. Comorbidity that would limit the ability to administer any functional measurements
  23. Has at the time of injection, a systemic or local infection at the site of injection
  24. 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)
  25. Known hypersensitivity to penicillin
  26. Known allergy to phenol red
  27. 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]
  28. Medical condition requiring radiation, chemotherapy or immunosuppression
  29. Have an active history of malignancy (except for basal cell carcinoma of the skin)
  30. 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
  31. Has obvious or documented alcohol or illicit drug addictions
  32. Is a prisoner in a correctional institution/facility
  33. Actively involved in litigation or workman's compensation
  34. Has participated in clinical studies evaluating investigational devices, pharmaceuticals or biologics within 6 months of randomization
  35. Bedridden, confined to a wheelchair, or unable to walk 50 m without the help of a walker, crutches, or cane
  36. Is currently taking prescription pain medication for any conditions other than ankle osteoarthritis.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Control Group
Single dose, 2.0 mL of 0.9% normal saline, administered via intra-articular injection administered to the affected tibiotalar joint.
Drug: "Drug/Placebo: 0.9% Normal Saline"
"Drug/Placebo: 0.9% Normal Saline"
Experimental: Investigational Group

Biological/Vaccine: Axolotl Ambient

Axolotl Ambient is an allogeneic amniotic intraarticular injection therapy consisting of a growth factor and cytokine-rich fluid derived from human amnion cells.

Other Names:

• CA20
Biological: Axolotl Ambient
Axolotl Ambient is an allogeneic amniotic intra-articular injection therapy consisting of a growth factor and cytokine-rich fluid derived from human amnion cells.
Other Names:
  • CA20

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change From Baseline in Ankle Osteoarthritis Scale (AOS; 48 hr Recall) Pain Subscale
Time Frame: 4-weeks, 3-months, and 6-months
The Ankle Osteoarthritis Scale (AOS) pain subscale goes from 0 (No pain) -100 (The worst imaginable).
4-weeks, 3-months, and 6-months
Change From Baseline for Ankle Osteoarthritis Scale (AOS; 48 hr Recall) Function Subscale
Time Frame: 4-week, 3 Months, 6-months
The Ankle Osteoarthritis Scale (AOS) functions subscale goes from 0 (No difficulty) -100 (So difficult, unable).
4-week, 3 Months, 6-months
Change From Baseline for Foot and Ankle Outcome Score (FAOS) for Pain Subscale
Time Frame: 4-weeks, 3-months, 6-months
A score of 100 represents no pain. A score of 0 constant pain.
4-weeks, 3-months, 6-months
Change From Baseline for Foot and Ankle Outcome Score (FAOS) for Function Subscale
Time Frame: 4-weeks, 3-months, 6-months
100 represents perfect health and 0 represents extreme problems and complete functional limitation. .
4-weeks, 3-months, 6-months
Proportion of Patients Achieving Composite Clinical Success (CCS).
Time Frame: 4-weeks, 3-months, 6-months

CCS defined as a patient meeting all of the three following criteria:

  1. Improvement in AOS (Pain and Function) or FAOS scores (Pain and ADL) of at least 20% from baseline
  2. No surgical intervention or prescription pain medications for ankle OA
  3. No treatment or procedure-related serious adverse events
4-weeks, 3-months, 6-months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Incidence of Adverse Events
Time Frame: Post-procedure follow-up assessments: 4 weeks (+/-7days), 3 Months (+/- 14 days), 6 Months (+/- 30 days), 12 Months (+/- 60 days), and unscheduled visits (up to 19 months)
Proportion of subjects experiencing at least (1) adverse events.
Post-procedure follow-up assessments: 4 weeks (+/-7days), 3 Months (+/- 14 days), 6 Months (+/- 30 days), 12 Months (+/- 60 days), and unscheduled visits (up to 19 months)
FAOS Subscales Quality of Life (QoL)
Time Frame: 4-week, 3-month, 6-month
0 (most severe problems) to 100 (no problems/best possible qualify of life)
4-week, 3-month, 6-month
Visual Analog Scale (VAS) for Ankle Pain (Average During Last 48 Hours)
Time Frame: 4 weeks, 3-months, 6-months
100 millimeter scale 0mm - No Pain and 100mm - Worst Imaginable Pain
4 weeks, 3-months, 6-months
VAS Ankle Pain (Worst During Last 48 Hours)
Time Frame: 4-weeks, 3-months, 6-months
100 millimeter scale 0mm - No Pain and 100mm - Worst Imaginable Pain
4-weeks, 3-months, 6-months
EuroQOL-5 Dimension-5 Level (EQ-5D-5L) Quality of Life Scale
Time Frame: 4-weeks, 3-months, 6-months
0 to 100 scale - 0 the worst health you can imagine to 100 the best health you can imagine.
4-weeks, 3-months, 6-months
Working Status
Time Frame: Baseline, 4-weeks, 3-months, 6-months
Not working, unrelated to ankle Not working, related to ankle Working with major limitations related to ankle Working without limitations related to ankle
Baseline, 4-weeks, 3-months, 6-months
K-L Grade From Weightbearing X-ray at Baseline and 6 Months
Time Frame: Baseline, 6-months
Grade 2 Definite osteophytes with mild to moderate joint space narrowing; early radiographic OA Grade 3a Significant osteophytes and joint space narrowing, but greater than 50% of the joint space remains preserved Grade 3b Severe joint space narrowing with less than 50% remaining joint space, approaching end-stage disease but not completely bone-on-bone Grade 4 Near complete or complete loss of joint space with substantial deformity (end-stage OA)
Baseline, 6-months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Axolotl Biologix

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Robert S. Kellar, PhD, Chief Science Officer (CSO)
  • Study Director: Aaron J. Tabor, PhD, CTBS, V.P. of Clinical Operations

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 10, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 10, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 8, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 21, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 25, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 7, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CA-2021-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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