Mallinckrodt plc, a leading global specialty pharmaceutical company, announced it has completed enrollment of the company's ongoing Phase 4 clinical trial of HP Acthar Gel for Rheumatoid Arthritis (RA) patients. The study is assessing the efficacy and safety of HP Acthar Gel in RA patients with persistently active disease. Target enrollment was 230 patients, and that goal has been exceeded.

"This is an exciting milestone achievement in this important clinical trial," said Steven Romano, MD, Executive Vice President and Chief Scientific Officer at Mallinckrodt. "As prescribers consider the potential benefit HP Acthar Gel may provide for appropriate RA patients with persistent disease activity, we are hopeful the findings from this study will help guide those decisions."

H.P. Acthar Gel is U.S. Food and Drug Administration (FDA)-approved as adjunctive therapy for short-term administration to tide the patient over an acute episode or exacerbation in rheumatoid arthritis including juvenile rheumatoid arthritis (selected cases may require low-dose maintenance therapy.

Mallinckrodt recently reported interim findings of the study at the Annual European Congress of Rheumatology (EULAR 2018). Details on that data presentation are available here. As the study continues to progress, the company plans to present additional data at future conferences.

Mark Trudeau, President and Chief Executive Officer at Mallinckrodt, said, "Our clinical programs for HP  Acthar Gel are conducted specifically to further establish its clinical utility in tough-to-treat patient populations, including approved, later-line indications outside infantile spasms, where the drug is considered standard of care. It is our intent to use the data from these programs to better inform prescribers, facilitating access for appropriate patients in both commercial plans and government programs."

The study is a Phase 4, multicenter, two-part study assessing the efficacy and safety of H.P. Acthar Gel in adult subjects with rheumatoid arthritis with persistently active disease that has completed enrollment. Part 1 is an Open Label Period in which all eligible subjects receive H.P. Acthar Gel for 12 weeks. After 12 weeks of treatment with H.P. Acthar Gel, subjects will be evaluated for treatment response using the Disease Activity Score 28-joint count Erythrocyte Sedimentation Rate (DAS28-ESR). Subjects who have achieved low disease activity will enter a double-blind randomized maintenance period (Part 2) and be randomized in a 1:1 ratio to receive either H.P. Acthar Gel or matching placebo for an additional 12 weeks.

The trial is fully enrolled, and all subjects are patients with persistently active RA despite treatment with corticosteroids and conventional synthetic and/or biologic disease-modifying anti-rheumatic drugs (DMARDs) for the primary outcome. The primary endpoint in this study is the proportion of subjects with DAS28-ESR <3.2 at Week 12. The Secondary Outcome Measures include the proportion of subjects who maintained DAS28-ESR <3.2 from Week 12 through Week 24.

RA is an autoimmune disease. It is a chronic condition that causes pain, stiffness, and swelling of the joints - all symptoms caused by inflammation. An estimated 1.5 million US adults are living with RA.1 Treatment is aimed at stopping inflammation to put the disease in remission and relieve symptoms.