Health Canada recent approvals in rare disease cont'd

In July 2024, HC approved ZILBRYSQ for treating generalized myasthenia gravis (gMG)[PM]. The FDA (USA) and EMA (Europe) approved the product in October and December 2023, respectively [?]. gMG is a rare autoimmune disorder. The immune system attacks the connection between nerves and muscles, leading to muscle weakness. This condition occurs later in life between 40 to 60 years old. This progressive disease is debilitating and life-threatening. The initial symptoms can be eyelid drooping and difficulty keeping the mouth closed. Over time, more severe symptoms appear, like difficulty swallowing, leg paralysis and difficulty breathing. UCB Pharma sponsored the development of ZILBRYSQ, which interferes with the immune system to prevent damage to these connections. In the RAISE study, patients improved functionality over standard care with an acceptable safety profile. The improvement is significant at 12 weeks and continues to improve over time.

In June 2024, HC approved WAINUA to treat hereditary transthyretinmediated amyloidosis (hATTR) [PM]. The FDA (USA) approved the product in December 2023 [Press]. hATTR is a rare genetic debilitating disease that leads to peripheral nerve damage. A mutation in the gene transthyretin (TTR) causes the production of a dysfunctional TTR protein. These TTR proteins form aggregations and cause nerve damage. Within five years of diagnosis, patients present with motor disabilities. Without treatment, the genetic disorder is generally fatal within a decade [Cortese]. AstraZeneca and Ionis Pharma sponsored the development of WAINUA, which reduces the production of TTR proteins. In the NEUROTTRansform study, patients treated with Wainua demonstrated consistent and sustained significant clinical benefits with an acceptable safety profile. The three significant clinical benefits are reduced serum TTR concentration, reduced nerve impairment and improved quality of life.

Approved in February 2024, MYALEPTA became the first and only treatment available to treat lipodystrophy, a life-treating ultra-rare genetic disorder characterized by complete or partial absence of fat tissue (2). Diagnosing lipodystrophy can be complex because less than 200 Canadians could be afflicted, and the clinical presentation varies greatly depending on the mutations involved. In these patients, lack of fat tissue impacts the leptin production, a hormone crucial in regulating hunger and energy balance. They develop several complications, such as severe insulin resistance (diabetes), hypertriglyceridemia, renal failure, and cardiovascular disease at a very young age (3). Myalepta is a leptin replacement therapy that addresses the central issue of this syndrome with a meaningful reduction of blood sugar markersandtriglyceridesinheavilypre-treatedpatients(4).