Based on positive data from the dose-ranging portion of the study, Sponsor decided as of May 28, 2024 not to move forward with the previously designed global ATX101-TKA-003 study.

This is a Phase 2B randomized, double blind, active controlled, multi-center clinical trial to evaluate the safety and efficacy of ATX-101 in participants following total knee arthroplasty. The following is short title and acronym for the study: Study Assessing Pain Relief after Replacement of the Knee (SPARK)

Inclusion Criteria:

• Primary indication of total knee arthroplasty is knee pain due to osteoarthritis or post-traumatic arthritis.
• Scheduled to undergo primary unilateral total knee arthroplasty with a cemented prosthesis, without use of a surgical drain, and under bupivacaine spinal anesthesia (dextrose is permitted).
• American Society of Anesthesiology (ASA) Physical Classification System of class 1, 2 or 3.

Exclusion Criteria:

• Has a planned concurrent surgical procedure.
• Has had any previous arthroplasty, unicompartmental knee arthroplasty or total knee arthroplasty in the study knee or previous arthroplasty, unicompartmental knee arthroplasty, or total knee arthroplasty in the contralateral knee within 6 months prior to screening.
• Has been administered any type of intra-articular injection within 3 months of surgery in the trial knee.
• Immunocompromised or has a known history of Hepatitis B, human immunodeficiency virus (HIV), or Hepatitis C.
• Routinely take opioid analgesics and are expected to require opioid analgesics in the postsurgical period that is not strictly related to the trial.
• Unable to abstain from opioid use for knee pain within 14 days of surgery.
• Has been administered systemic steroids within 14 days prior to surgery.
• Has been administered any local anesthetic within 5 days prior to the scheduled surgery.
• Screening electrocardiogram (ECG) with significant abnormalities associated with significant heart disease.
• Has a contraindication or a known suspected history of allergy, hypersensitivity or idiosyncratic reaction to trial medications.
• Has uncontrolled depression, anxiety, psychiatric, or neurological disorder that might interfere with trial study assessments.
• Has a medical condition or receiving medication such that, in the opinion of the investigator, participating in the trial would pose a health risk to the subject or might interfere with the study outcome.
• Has a known or suspected history of drug or alcohol abuse. A subject with a history of alcohol use disorder that has ≥10 years sobriety will be permitted.
• Has received/used an investigational drug, product, or device for a clinical trial within 30 days of screening. COVID-19 vaccines are permitted if the subject is not in a clinical trial for the vaccine.
• Has a Body Mass Index (BMI) ≥45 kg/m2