Safety, biodistribution, and exploratory clinical outcomes of a novel intra-articular IL-1Ra gene therapy (PCRX-201) in moderate-to-severe knee osteoarthritis: 2-year results of a phase 1 study
Authors' conclusion
A single intra-articular injection of PCRX-201 demonstrated safety and localised distribution within the knee.
Study context
- Population
- Adults aged 30 to 80 years with symptomatic (WOMAC pain ≥ 5 and ≤ 9, 0–10 scale) and radiographic (Kellgren-Lawrence grade 2–4) knee OA
- Participants
- 36 vs 36
- Comparison
- Single intra-articular PCRX-201 at 1 of 3 doses, without (part 1) or with (part 2) intra-articular methylprednisolone acetate pretreatment
- PCRX-201 (part 1)n = 36
- GC pretreatment + PCRX-201 (part 2)n = 36
- Outcome
- Safety
- Follow-up
- Week 104
Methodological detailsopen-label, dose-ranging (3 doses), 2 parts
- Open-label
- Dose-ranging (3 doses)
- 2 parts
Main finding
As reported in the abstract
Transient treatment-related knee effusion (most common AE; safety, primary endpoint)
| Group | Value | Denominator |
|---|---|---|
| Glucocorticoid pretreatment | 36.1% | 36 |
| No glucocorticoid pretreatment | 61.1% | 36 |
Value
Glucocorticoid pretreatment36.1%
No glucocorticoid pretreatment61.1%
Denominator
Glucocorticoid pretreatment36
No glucocorticoid pretreatment36
Secondary outcomes
Biodistribution
- Very limited biodistribution outside the knee; participants with detectable PCRX-201 in plasma on days 1 and 4 postinjection
- 2
Study discontinuation · week 104
- Participants discontinued, 33/72
- 45.8%
Exploratory: pain, stiffness, function · week 104
- Sustained improvements across doses and groups in those remaining, regardless of preexisting neutralising antibody levels; greater improvements in the GC-pretreated group
Safety
Transient treatment-related knee effusion (most common AE) · week 104
Denominator Glucocorticoid pretreatment 36 · No glucocorticoid pretreatment 36
Original publication
Safety, biodistribution, and exploratory clinical outcomes of a novel intra-articular IL-1Ra gene therapy (PCRX-201) in moderate-to-severe knee osteoarthritis: 2-year results of a phase 1 study. Ann Rheum Dis. Published 4 August 2026. doi:10.
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