BRISBANE, Calif., August 6, 2026
Pacira BioSciences announced the publication of positive two-year Phase 1 clinical trial results for PCRX-201 (enekinragene inzadenovec) in the Annals of the Rheumatic Diseases, highlighting the investigational gene therapy’s favorable safety profile and sustained improvements in pain, stiffness, and physical function in patients with moderate-to-severe knee osteoarthritis (OA). The study demonstrated that a single intra-articular injection of PCRX-201 was well tolerated across all dose cohorts, while exploratory clinical outcome measures showed durable benefits throughout 104 weeks of follow-up among patients who remained in the trial. The publication further supports the advancement of PCRX-201 into later-stage development as the company’s Phase 2 ASCEND trial continues, with its first topline data expected by the end of 2026.
Phase 1 Trial Demonstrates Long-Term Safety and Clinical Benefit
The open-label Phase 1 study enrolled 72 adults aged 30 to 80 years with radiographically confirmed moderate-to-severe knee osteoarthritis. Participants received a single local injection of PCRX-201, with half of the patients receiving methylprednisolone pretreatment before gene therapy administration to improve tolerability and enhance vector transduction. The primary endpoint evaluated safety, while secondary and exploratory assessments measured pain, stiffness, physical function, and systemic biodistribution through two years. Investigators reported that glucocorticoid pretreatment was associated with lower rates of joint effusion and greater clinical improvement, leading Pacira to incorporate this approach into the ongoing Phase 2 ASCEND study. The encouraging findings strengthen confidence that PCRX-201 may provide long-lasting therapeutic effects beyond the three-to-six-month duration typically achieved with currently available osteoarthritis treatments.
PCRX-201 Targets the Underlying Biology of Knee Osteoarthritis
Unlike conventional therapies that primarily manage symptoms, PCRX-201 is designed to address the biomechanical and inflammatory mechanisms responsible for knee osteoarthritis progression. Built on Pacira’s proprietary high-capacity adenovirus (HCAd) vector platform, the investigational gene therapy enables efficient delivery of large genetic payloads while allowing local administration and the potential for repeat dosing if needed. The HCAd platform is also designed to improve manufacturing efficiency, enabling lower therapeutic doses, increased production capacity, and potentially lower manufacturing costs compared with traditional viral vector technologies. PCRX-201 has already received both Regenerative Medicine Advanced Therapy (RMAT) designation from the U.S. Food and Drug Administration (FDA) and Advanced Therapy Medicinal Product (ATMP) designation from the European Medicines Agency (EMA), making it the first gene therapy for knee osteoarthritis to achieve these regulatory recognitions.
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Phase 2 ASCEND Trial Advances Toward Key Clinical Milestones
Building on the promising Phase 1 results, Pacira BioSciences continues to advance the Phase 2 ASCEND clinical trial, which recently initiated Part B enrollment following a successful transition to a scalable manufacturing process for PCRX-201. The company believes the therapy has the potential to transform treatment for the more than 15 million people in the United States living with knee osteoarthritis by delivering durable disease-modifying benefits from a single local injection. If the ongoing Phase 2 trial confirms the long-term safety and efficacy observed in the earlier study, PCRX-201 could represent a significant advancement in the evolving field of gene therapy for musculoskeletal diseases, providing patients with a longer-lasting alternative to existing pain management options
Source:Pacira BioSciences,, press release
