FDA Approves First Drug for Primary Hyperoxaluria Type 1

The US Food and Drug Administration (FDA) has approved lumasiran (Oxlumo) as the first drug for rare genetic disorder primary hyperoxaluria type 1 (PH1).

The approval, granted to Alnylam Pharmaceuticals, provides a therapeutic resolve to the condition which affects approximately 3 persons per 1 million in North American and Europe combined, and can result in kidney function and organ damage.

As the FDA additionally noted in its approval, the indication comes from collaborative work among experts and community leaders coordinated by the Oxalosis & Hyperoxaluria Foundation and the Kidney Health Initiative.

“The approval of Oxlumo represents a great triumph of community involvement to address a rare disease. It is a result of input from patients, treating physicians, experts and sponsors at a patient-focused drug development meeting and through other collaborative efforts,” said Norman Stockbridge, MD, PhD, director of the Division of Cardiology and Nephrology in the FDA’s Center for Drug Evaluation and Research, in a statement.

Primary hyperoxalurias (PHs) are driven by excess production of oxalate, a substance commonly consumed in food. As the most severe form of the condition, PH1 activity can frequently combine with calcium to cause kidney stones and deposits, leading to progressing kidney damage and even failure.

Lumasiran was evaluated in a randomized, placebo-controlled study in patients with PH1 aged 6 years and older, as well as an open-label study in patients younger than 6 years. Patients were aged 4 months to 61 years old at the first dose.

In the placebo-controlled trial, 26 patients received a monthly lumasiran injection followed by maintenance dose every 3 months, versus 13 patients who received placebo. Investigators assessed for a primary endpoint of oxalate measure via urine over 24 hours.

Treated patients reported a mean 65% reduction on oxalate, versus just 12% reduction in patients on placebo. More than half (52%) of treated patients achieved normal 24-hour urinary oxalate levels by the sixth month of assessment, versus none on placebo.

In the open-label trial, 16 patients all received lumasiran, and reported a mean 71% in urinary oxalate by the sixth month of assessment.

Common adverse events in treated patients included injection site reaction and abdominal pain.

Lumasiran originally received Orphan Drug Designation, Breakthrough Therapy Designation, and a rare pediatric disease priority review voucher from the FDA.