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Active, not recruitingNCT04119687Updated Sep 17, 2026

Study to Evaluate the Safety and Tolerability of FX201 in Patients With Osteoarthritis of the Knee

A Phase 1 interventional study of FX201 in Osteoarthritis, Knee, sponsored by Pacira Pharmaceuticals, Inc. Active, not recruiting at 6 sites in United States. Open to participants aged 30 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-17.

Sponsored by Pacira Pharmaceuticals, Inc · Phase 1, Interventional, and Treatment

Phase
Phase 1
Study type
Interventional
Enrollment
72
Allocation
Non-randomized
Ages
30 Years to 80 Years
Sex
All
01

Study summary

This two-part study will be conducted in male and female patients, 30 - 80 years of age with painful OA of the index knee with Kellgren-Lawrence (K-L) Grade 2, 3 or 4.

Part 1 - Single Ascending Dose (SAD) Phase: Up to three ascending doses of FX201 will be tested in cohorts of 5-8 patients. Each patient will only receive one injection of FX201. An independent Data Monitoring Committee (DMC) will review safety and guide the conduct of the study.

Part 2 - Expansion Phase: Up to an additional 35 patients will be enrolled at each dose level reviewed by the DMC. Each patient will only receive one injection of FX201.

Read the detailed description

This two-part study will be conducted in male and female patients, 30 - 80 years of age with painful OA of the index knee with Kellgren-Lawrence (K-L) Grade 2, 3 or 4.

Part 1 - SAD Phase: Up to three ascending doses of FX201 (low dose, mid dose and high dose) will be tested in cohorts of 5-8 patients. Each patient will only receive one injection of FX201. A maximum of 24 patients will be enrolled (range 15 to 24).

When a minimum of 4 weeks have elapsed since the last patient of the current cohort has been treated, all safety data will be collected and reviewed by an independent Data Monitoring Committee (DMC). After evaluating cohort safety data, the DMC will evaluate continuing the trial and initiating treatment in the next dosing cohort as well as expanding enrollment in dose level(s).

Part 2 - Expansion Phase: After the DMC has met to review safety data from each Cohort and has recommended expanding dose level(s), enrollment slots for dose levels reviewed by the DMC will be opened. A maximum of 105 patients [up to an additional 35 patients per dose level (up to 20 FX201 alone and up to 15 FX201 with IA methylprednisolone 40 mg/mL pre-treatment)].

02

Conditions studied

  • Osteoarthritis, Knee
03

In context

Osteoarthritis, Knee

3,292 studies on the registry are indexed under Osteoarthritis, Knee; 623 are open to participants now.

This study's enrollment of 72 is close to the median of 68 across 2,714 interventional studies indexed under Osteoarthritis, Knee.

Browse Osteoarthritis, Knee studies →

Lead sponsor

Pacira Pharmaceuticals, Inc is the lead sponsor of 102 studies on the registry; 3 are open to participants now.

Of its 26 completed or terminated interventional studies of FDA-regulated products, 17 (65%) have results posted.

Browse Pacira BioSciences, Inc. studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
30 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Written consent to participate in the study
  • Male or female 30 to 80 years of age, inclusive, on the day of enrollment (Day 1)
  • (BMI) ≤ 40 kilograms per meters squared (kg/m2)
  • Clinical diagnosis of OA of the knee on the American College of Rheumatology criteria (Altman, 1986) with radiologic evidence of OA (K-L Grade 2 or 3 for SAD Phase Cohort A and K-L Grade 2, 3 or 4 for SAD Phase Cohorts B and C and the Expansion Phase) at the index joint at the screening visit
  • Moderate pain in the index joint
  • Failed two or more types of conservative therapy for index knee osteoarthritis (e.g., structured exercise programs, topical or oral non-steroidal anti-inflammatory therapies); or failed one prior type of conservative therapy and at least one prior index knee IA treatment ( or hyaluronic acid)
  • Sexually active females and males agree to use highly effective methods of

Exclusion criteria

Exclusion Criteria:

  • Reactive arthritis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, or arthritis associated with inflammatory bowel disease
  • History of or current infection in the index knee joint
  • Inability to undergo Magnetic Resonance Imaging (MRI) due to presence of surgical hardware or other foreign body in the index knee
  • Unstable index knee joint (e.g., torn anterior cruciate ligament, etc.) within 12 months of Screening
  • Any IA drug/biologic use within 6 months of Screening or 5 half-lives (whichever is longer) (e.g., IA , IA hyaluronic acid, rich plasma injection, stem cells, prolotherapy and amniotic fluid injection, etc.)
  • Cold or radiofrequency nerve ablation of the index knee within 12 months of Screening
  • Arthroscopic or open surgery on the index knee within 12 months of Screening or planned/anticipated surgery on the index knee for the study period
  • Anticipated major surgery during the study period
  • Laboratory values that meet exclusion criteria
  • abnormality at Screening or Baseline judged
  • Use of immunomodulators, , or chemotherapeutic agents within 5 years of Screening
  • Use of any other drug, biologic or device within 3 months of Screening
  • Any systemic or local bacterial or viral infection requiring IV antibiotics or antivirals within 4 weeks of Screening or oral antibiotics or antivirals within 2 weeks of Screening
  • Known allergy or sensitivity to methylprednisolone
  • Any other clinically significant acute or chronic medical conditions (e.g., bleeding disorder) that, in the judgment of the Investigator, would preclude the use of an IA injection or that could compromise patient safety, limit the patient's ability to complete the study, and/or compromise the objectives of the study

Note: Other protocol defined inclusion/exclusion criteria apply.

Terms in these criteria, in plain language(8)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

ECG (electrocardiogram)

A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

05

Study design

Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Sequential assignment
Masking
None (open label)
Enrollment
72 participants (actual)

Study arms

  • Experimental
    Low Dose FX201

    Single low dose FX201 injection

    Biological: FX201

  • Experimental
    Mid Dose FX201

    Single mid dose FX201 injection

    Biological: FX201

  • Experimental
    High Dose FX201

    Single high dose FX201 injection

    Biological: FX201

Interventions

  • BiologicalFX201

    FX201, humantakinogene hadenovec, is a novel interleukin-1 receptor antagonist (IL-1Ra) gene therapy for IA administration that is being developed for the treatment of patients with OAK.

06

What researchers measure

Primary outcomes

  1. Primary Outcome Measure: Incidence of treatment emergent adverse events after a single intra-articular (IA) injection of FX201 (safety and tolerability)

    Incidence of treatment emergent adverse events after a single intra-articular (IA) injection of FX201

    Time frame: Baseline to Week 104

Secondary outcomes

  1. Secondary Outcome Measure: Characterization of the systemic biodistribution of FX201 as seen through the percentage of patients positive for FX201 at Baseline, Day 1, Day 2, Week 1, Week 2, Week 3, and Week 4

    The percentage of patients positive for FX201 at select timepoints

    Time frame: Baseline, Day 1, Day 2, Week 1, Week 2, Week 3, Week 4

07

Study locations

6 sites
08

References and documents

Publications

  • Mehta S, He T, Bajpayee AG. Recent advances in targeted drug delivery for treatment of osteoarthritis. Curr Opin Rheumatol. 2021 Jan;33(1):94-109. doi: 10.1097/BOR.0000000000000761. PubMed 33229973 ↗
09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Mar 2020 to primary completion in Nov 2023, 44 months.

Of 34 industry-sponsored phase 1 interventional studies under Osteoarthritis, Knee, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 21. This study's 44 months is above that.

Counting every sponsor, half of 61 studies reached it within 20 months; a quarter within 11 and three quarters within 44.

How these figures are worked out, and which studies are left out of them.

Registered
Oct 3, 2019
First posted
Oct 8, 2019
StartActual
Mar 2, 2020
Primary completionActual
Nov 28, 2023
CompletionEst.
Nov 28, 2026
Last update
Sep 17, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 17, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04119687
Lead sponsor
Pacira Pharmaceuticals, Inc
Responsible party
Sponsor
First posted
Oct 8, 2019
Start date
Mar 2, 2020
Primary completion
Nov 28, 2023
Completion
Nov 28, 2026 (estimated)
Last update
Sep 17, 2026

Study contacts

Warren Rizzo, MD
study director · Pacira Pharmaceuticals, Inc

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.

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Discussion

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