Acute Postoperative PainPhase 2SPARKNCT05260008
Study Assessing Pain Relief After Replacement of the Knee
A Phase 2 study testing ATX-101 and bupivacaine hydrochloride without epinephrine in people with Acute Postoperative Pain, run by Allay Therapeutics, Inc. at 13 sites in 3 countries.
Trial summary
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) Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Acute Postoperative Pain
- What is being tested?
- ATX-101 and bupivacaine hydrochloride without epinephrine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 112 participants
- Where
- 13 sitesin 3 countries
- Study dates
- 7 Jun 2022to 15 Jan 2024
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
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- 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
Trial locations and contacts
13 sites in 3 countries.
13 sites in 3 countries
United Kingdom6 sites
Department of Trauma and Orthopaedic Surgery, Addenbrooke's Hospital
Cambridge, Cambridgeshire, CB2 0QQ
Chapel Allerton Hospital C/O The Leeds Teaching Hospitals NHS Trust
Leeds, West Yorkshire, LS7 4SA
Nottingham Elective Orthopaedic Service, Nottingham University Hospitals
Nottingham, Nottinghamshire, NG5 1PB
Robert Jones & Agnes Hunt Orthopaedic Hospital
Oswestry, Shropshire, SY10 7AG
Southampton General Hospital
Southampton, Hampshire, SO16 6YD
Royal National Orthopaedic Hospital
Stanmore, Middlesex, HA7 4LP
Australia5 sites
Royal Adelaide Hospital / PARC Clinical Research
Adelaide, South Australia, 5000
St Andrew's Private Hospital
Adelaide, South Australia, 5000
Prince of Wales Private Hospital
Sydney, New South Wales, 2031
John Flynn Private Hospital
Tugun, Queensland, 4224
The Avenue Private Hospital
Windsor, Victoria, 3181
Canada2 sites
Durham Bone and Joint Specialists
Ajax, Ontario, L1S 7K7
London Health Sciences Centre - University Hospital
London, Ontario, C9 124
About this study
Official title: A Phase 2B, Randomized, Double Blind, Active Comparator, Multicenter, Safety, and Efficacy Trial of ATX-101 in Subjects Undergoing Total Knee Arthroplasty
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)
- Conditions
- Acute Postoperative Pain
- Being tested
- ATX-101, bupivacaine hydrochloride without epinephrine
- Keywords
- postoperative pain, post-surgical pain total knee arthroplasty, total knee replacement ATX-101, bupivacaine, bupivacaine implant
- Medical subject headings
- Pain, Postoperative
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ATX-101Drug
ATX-101 (bupivacaine) implant, one-time administration into the surgical site
ATX-101Drug
ATX-101 (bupivacaine) implant, one-time administration into the surgical site
bupivacaine hydrochloride without epinephrineDrug
bupivacaine hydrochloride (125 mg) without epinephrine via local infiltration and/or nerve block
| Study group | Role | What they receive |
|---|---|---|
| ATX-101 Dose A | Experimental | ATX-101 Dose A Receives: Drug: ATX-101 |
| ATX-101 Dose B | Experimental | ATX-101 Dose B Receives: Drug: ATX-101 |
| bupivacaine hydrochloride | Active comparator | bupivacaine hydrochloride without epinephrine via local infiltration and/or nerve block Receives: Drug: bupivacaine hydrochloride without epinephrine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Area Under the Curve (AUC) for the Numeric Rating Scale at Rest (NRS-R) of Pain Intensity.
NRS-R for pain intensity is an 11-item scale from 0 to10 where participants rank the level of pain intensity. The NRS scale goes from No Pain (0) to Worst Imaginable Pain (10).
Measured: from 30 minutes post-surgery through hour 168 (Day 8)
Secondary outcomes (3)
Percentage of Subject Who Remain Opioid Free.
Opioid free is defined as no opioid rescue medication was recorded for the timepoint displayed and onwards.
Measured: Surgical Closure to Day 30
Total Post-surgical Use of Rescue Opioid Medications.
Total post-surgical use of rescue opioid medications (days).
Measured: Surgical Closure to Day 30, Opioid consumption is summarized descriptively every 24-hour period through Day 30
Time to First Rescue Opioid Medication.
Time to first postsurgical use of rescue opioid medication (days).
Measured: Surgical Closure to Day 30
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Mar 2022
- Study start7 Jun 2022
- Primary completion15 Jan 2024
- Study completion15 Jan 2024
Why it stopped: 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.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Acute Postoperative PainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This is a Phase 2B, randomized, double blind, active comparator multicenter trial in participants undergoing total knee arthroplasty.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 112 participants (actual)
Sponsor and investigators
- Lead sponsor
- Allay Therapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05260008
- Sponsor's protocol ID
- ATX-101-TKA-003
- Acronym
- SPARK
- Status last verified
- Jul 2025
- First submitted
- 18 Feb 2022
- Last updated
- 14 Aug 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2B, Randomized, Double Blind, Active Comparator, Multicenter, Safety, and Efficacy Trial of ATX-101 in Subjects Undergoing Total Knee Arthroplasty
- ClinicalTrials.gov ID
- NCT05260008
- Acronym / sponsor ID
- SPARK / ATX-101-TKA-003
- Conditions
- Acute Postoperative Pain
- Keywords
- postoperative pain, post-surgical pain total knee arthroplasty, total knee replacement ATX-101, bupivacaine, bupivacaine implant
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: 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.
- Enrolment
- 112 participants (actual)
- Lead sponsor
- Allay Therapeutics, Inc.Industry (pharma, biotech, devices)
- Study start
- 7 Jun 2022 (actual)
- Primary completion
- 15 Jan 2024 (actual)
- Study completion
- 15 Jan 2024 (actual)
- First posted
- 2 Mar 2022 (actual)
- Results
- Posted 14 Aug 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
- Model description
- This is a Phase 2B, randomized, double blind, active comparator multicenter trial in participants undergoing total knee arthroplasty.
| Arm | Type | Receives |
|---|---|---|
| ATX-101 Dose A | Experimental | Drug: ATX-101ATX-101 Dose A |
| ATX-101 Dose B | Experimental | Drug: ATX-101ATX-101 Dose B |
| bupivacaine hydrochloride | Active comparator | Drug: bupivacaine hydrochloride without epinephrinebupivacaine hydrochloride without epinephrine via local infiltration and/or nerve block |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- 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.
Key exclusion criteria (15 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ATX-101ATX-101 (bupivacaine) implant, one-time administration into the surgical site | Drug | ATX-101 Dose A |
| ATX-101ATX-101 (bupivacaine) implant, one-time administration into the surgical site | Drug | ATX-101 Dose B |
| bupivacaine hydrochloride without epinephrinebupivacaine hydrochloride (125 mg) without epinephrine via local infiltration and/or nerve block | Drug | bupivacaine hydrochloride |
Primary outcome
Area Under the Curve (AUC) for the Numeric Rating Scale at Rest (NRS-R) of Pain Intensity.
Time frame: from 30 minutes post-surgery through hour 168 (Day 8)
NRS-R for pain intensity is an 11-item scale from 0 to10 where participants rank the level of pain intensity. The NRS scale goes from No Pain (0) to Worst Imaginable Pain (10).
3 secondary outcomes
Percentage of Subject Who Remain Opioid Free.
Time frame: Surgical Closure to Day 30
Total Post-surgical Use of Rescue Opioid Medications.
Time frame: Surgical Closure to Day 30, Opioid consumption is summarized descriptively every 24-hour period through Day 30
Time to First Rescue Opioid Medication.
Time frame: Surgical Closure to Day 30
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Aug 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
13 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing ATX-101 and bupivacaine hydrochloride without epinephrine in people with Acute Postoperative Pain, run by Allay Therapeutics, Inc. at 13 sites in 3 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 14 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 13 sites in United Kingdom, Australia, Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 14 Aug 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Area Under the Curve (AUC) for the Numeric Rating Scale at Rest (NRS-R) of Pain Intensity. (time frame: from 30 minutes post-surgery through hour 168 (Day 8)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Aug 2025.