Alnylam Announces Pricing of Offering of $900 Million Convertible Senior Notes

One month after reporting positive results from the APOLLO-B phase 3 study of patisiran, an investigational RNAi therapeutic in development for the treatment of transthyretin-mediated (ATTR) amyloidosis with cardiomyopathy, Alnylam Pharmaceuticals raised $900 million in a convertible senior note offering due 2027 to private investors.

In addition, Alnylam granted the initial purchasers of the notes an option to purchase, for settlement within a 13-day period beginning on, and including, the date on which the notes are first issued, up to an additional $135.0 million aggregate principal amount of the notes. The offering is expected to close on September 15, 2022, subject to customary closing conditions.

The notes are senior, unsecured obligations of Alnylam and will accrue interest at a rate of 1.00 percent a year, payable semi-annually beginning on March 15, 2023, maturing on September 15, 2027, unless earlier converted, redeemed or repurchased. Before June 15, 2027, noteholders will have the right to convert their notes in certain circumstances and during specified periods.

Transthyretin-mediated (ATTR) amyloidosis is a rare, rapidly progressive, debilitating disease caused by misfolded transthyretin (TTR) proteins which accumulate as amyloid fibrils in multiple tissues including the nerves, heart, and gastrointestinal (GI) tract. There are two different types of ATTR amyloidosis – hereditary ATTR (hATTR) amyloidosis, caused by a TTR gene variant, and wild-type ATTR amyloidosis (wtATTR), which occurs without a TTR gene variant.

Patisiran, which is marketed as Onpattro, is an intravenously administered RNAi therapeutic targeting transthyretin (TTR). It is designed to target and silence TTR messenger RNA, thereby reducing the production of TTR protein before it is made. Reducing the pathogenic protein leads to a reduction in amyloid deposits in tissues. It is approved in the United States and Canada for the treatment of the polyneuropathy of hATTR amyloidosis in adults. It is also approved in the European Union, Switzerland, and Brazil for the treatment of hATTR amyloidosis in adults with stage 1 or stage 2 polyneuropathy, and in Japan for the treatment of hATTR amyloidosis with polyneuropathy.

The APOLLO-B phase 3 randomized, double-blind, placebo-controlled multicenter global study is designed and powered to evaluate the effects of patisiran on functional capacity and quality of life in patients with ATTR amyloidosis with cardiomyopathy.

The study met its primary endpoint of change from baseline in the 6-Minute Walk Test (6-MWT) at 12 months compared to placebo. The study also met the first secondary endpoint of change from baseline in quality of life compared to placebo, as measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ).

Patisiran also demonstrated an encouraging safety and tolerability profile, with deaths numerically favoring the patisiran arm. Five patients (2.8 percent) on patisiran and 8 patients (4.5 percent) on placebo died. The number of deaths in the all-cause mortality efficacy analysis was 4 in the patisiran arm and 10 in the placebo arm, determined in accordance with the pre-defined statistical analysis plan, which excluded death due to COVID-19, and treated cardiac transplant as a death event consistent with other studies in the field.

Author: Rare Daily Staff