PCRX 201 (enekinragene inzadenovec),showed sustained improvements in knee pain, stiffness, and function following a single local administration for mild,moderate, and severe osteoarthritis of the knee-Pacira BioSciences.

Pacira BioSciences Inc.  announced new data demonstrating its locally administered gene therapy candidate, PCRX 201 (enekinragene inzadenovec), provided sustained improvements in knee pain, stiffness, and function for up to two years following a single local administration in patients with mild, moderate, as well as severe osteoarthritis of the knee. The data was presented during a poster session at the 2025 Osteoarthritis Research Society International (OARSI) World Congress in Incheon, South Korea, on Friday, April 25, and Saturday, April 26.

The open-label, phase I  trial investigated the efficacy of PCRX -201 administered by ultrasound-guided intraarticular injection in 72 patients aged 30 to 80, stratified by structural severity of osteoarthritis of the knee. The research included participants with osteoarthritis of the knee graded at 2, 3 and 4 on the Kellgren-Lawrence (K/L) scale, a method for evaluating the severity of osteoarthritis on a scale of 0-4.

Participants were divided into two cohorts. The first cohort was administered one injection of PCRX -201 at a low, middle or high dosage. The second cohort received concurrent pretreatment with an intraarticular corticosteroid (methylprednisolone 40 mg) to improve tolerability and gene transfer.

Improvements in pain, stiffness and function from baseline were shown across both cohorts at all three doses and severity levels over the full 104-week study period; they were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index pain score (WOMAC-A), the stiffness score (WOMAC-B), and Knee Injury and Osteoarthritis Outcome Score (KOOS).

Patients in the corticosteroid -pretreated cohort achieved greater benefits (48%-65% reductions in pain and 53%-72% reductions in stiffness) than the first cohort (41%-58% reduction in pain and 33%-53% reduction in stiffness). Improvement was observed across all severity subgroups with the greatest improvement observed among individuals with K/L grade 2 osteoarthritis of the knee.

No serious treatment-emergent adverse events (TEAEs) related to the treatment or procedure were reported regardless of corticosteroid pretreatment or dose level administered. Treatment-related joint effusions (swelling) were the most common AE, occurring in 36% of patients who received corticosteroid pretreatment vs 61% of patients who were not pretreated. The majority of effusions were mild to moderate in severity and resolved in a median of 33 days among patients in the pretreated group. The percentage of participants with treatment related knee effusions was similar across subgroups.

Given these promising Phase I results, dosing is underway in a Phase II study of PCRX-201 (the ASCEND study) for the treatment of osteoarthritis of the knee.