Alnylam Reports Updated Positive Results from Phase 1/2 Study of Lumasiran in Patients with Primary Hyperoxaluria Type 1

Alnylam Pharmaceuticals announced updated positive results from its Phase 1/2 clinical study of lumasiran, an investigational, subcutaneously administered RNAi therapeutic targeting glycolate oxidase (GO) for the treatment of primary hyperoxaluria type 1 (PH1). Results were presented at the 2018 European Society for Paediatric Nephrology (ESPN) Annual Meeting on October 4 in Antalya, Turkey. The Company also announced the initiation of ILLUMINATE-A, a global Phase 3 pivotal trial of lumasiran in children and adults with PH1. The study will enroll approximately 30 patients and is designed in alignment with FDA with a primary endpoint based on reduction of urinary oxalate at six months. Alnylam expects to report topline results from ILLUMINATE-A in late 2019 and, if positive, submit filings for regulatory approval starting in early 2020.

New results from the Phase 1/2 study were as of a data cut-off date of August 15, 2018. Lumasiran demonstrated a mean maximal reduction in urinary oxalate of 75 percent (range: 43-87 percent) relative to baseline across cohorts dosed at 1 mg/kg monthly or 3 mg/kg monthly or quarterly (N=20). The mean reduction relative to baseline was 66 percent when measured 28 days post last dose. All patients (100 percent) achieved oxalate lowering to less than 1.5 times the upper limit of normal (less than 0.69 mmol/24hr/1.73m2). Among patients receiving 3 mg/kg monthly or quarterly doses of lumasiran (N=12), 83 percent achieved urinary oxalate levels within the normal range (less than 0.46 mmol/24hr/1.73m2). Furthermore, lumasiran-treated patients in all cohorts experienced a mean maximal decrease of 76 percent in the ratio of urinary oxalate to creatinine – a corroborative measure of oxalate reduction that addresses the variability that is inherent to 24 hour urine collections.

“We are pleased to present these data that we believe provide a strong foundation for lumasiran as an investigational RNAi therapeutic for the treatment of PH1, a devastating and life-threatening disease caused by overproduction of oxalate that deposits in the kidneys and other tissues. We’re also excited to have now initiated the ILLUMINATE-A Phase 3 pivotal study, which is expected to read out in late 2019, supporting a potential regulatory approval in 2020, if positive,” said Pritesh J. Gandhi, PharmD., Vice President and General Manager, Lumasiran program at Alnylam. “Given the lack of approved treatment options, we believe lumasiran has the potential to address the significant unmet need that PH1 represents.”

“PH1 is an ultra-rare disease characterized by an inevitable and progressive decline in kidney function leading to systemic manifestations and ultimately multi-organ dysfunction. Once the kidneys fail, the only viable therapeutic option is a dual liver/kidney transplant,” said Prof. Pierre Cochat, M.D., Ph.D., Reference Center for Rare Kidney Diseases, Lyon University Hospital, France; President, International Pediatric Nephrology Association (IPNA) and an investigator in the lumasiran study. “Given the profound unmet need in this disease setting, the Phase 1/2 results presented for lumasiran are encouraging, particularly in light of the clinically meaningful effect of lumasiran on lowering urinary oxalate for every patient relative to their baseline and with all patients achieving near normal levels of oxalate.”

The Phase 1/2 safety results in patients with PH1 were based on a median study duration of seven months (range: 5 to 14 months) since first dose. As of the data cut-off date, there were no discontinuations from study treatment. Serious adverse events (SAEs) were reported for one patient (33 percent) receiving placebo and five patients (25 percent) receiving lumasiran; none were related to study drug. The placebo patient experienced acute pyelonephritis and kidney stones. The lumasiran patients with SAEs included one patient with vomiting, one patient with abdominal pain, fever and vomiting, one patient with gastroenteritis, and two patients with kidney stones. Adverse events (AEs) were reported in three (100 percent) patients during placebo dosing and 19 (95 percent) patients after lumasiran dosing. The majority of AEs were mild or moderate in severity and were assessed as unrelated to study drug. Injection site reactions (ISRs) were reported in three (15 percent) patients receiving lumasiran. ISRs were mild or moderate in severity and were self-limiting. Lumasiran was not associated with any clinically significant adverse laboratory findings. In patients receiving lumasiran, plasma glycolate levels increased consistent with the pharmacology of lumasiran and results from healthy volunteers in Part A of the Phase 1/2 study. This increase was not associated with any safety findings.