According to GlobalData’s recent Niemann-Pick Type C (NPC): Opportunity Analysis and Forecast to 2031 report, the NPC market is expected to see significant growth during 2021–31. The three major markets (3MM: the US, Germany and the UK) will increase in market size from $128.35m last year to $188.35m in 2031, at a compound annual growth rate (CAGR) of 3.9%. This sales growth will be in line with a steadily increasing disease prevalence and the entrance of novel agents into the market. Several drugs in the pipeline have novel mechanisms of action (MOAs), including novel calcium channel regulator acetylleucine and cyclodextrin therapies, adrabetadex and Trappsol Cyclo.
NPC is a rare inherited disease resulting from the body’s inability to conduct intracellular transport of cholesterol and other lipids, leading to the abnormal accumulation of these substances in various bodily tissues, including brain tissue. NPC is highly variable and the age of onset and specific symptoms can vary, ranging from a fatal disorder within the first few months after birth (neonatal period) to a late-onset, chronic progressive disorder that remains undiagnosed well into adulthood. Major symptoms of the disease are neurological and developmental disorders, as well as hepatosplenomegaly, jaundice, cholestasis, bleeding disorders and, eventually, dysphagia and even respiratory failure in adults. Most cases are detected during childhood and progress to cause life-threatening complications by the second or third decade of life. NPC is caused by mutations in the NPC1 gene (NPC type 1C) or the NPC2 gene (NPC type 2C) and is inherited in an autosomal recessive manner.
The current treatment for NPC involves the use of miglustat, a glucosylceramide synthase (GCS) inhibitor, delaying the onset of neurological symptoms that occur as a result of NPC. Miglustat is the only marketed therapy currently in this space and can be prescribed for the treatment of neurological disease that results from NPC, but not the other physiological symptoms such as hepatosplenomegaly, dystonia and dysphagia. There are two branded miglustat therapies available across the 3MM, with the US market having Johnson and Johnson’s (J&J, US) Zavesca and also generic miglustat available, but neither of these are approved for the treatment of NPC, so physicians prescribe this therapy off-label. Germany and the UK have two marketed miglustat therapies: Piramal Enterprises’ (India) Yargesa and J&J’s Zavesca. The patents for these miglustat therapies have expired and the NPC market remains in urgent need of therapies with novel MOAs that are able to either reverse the decline of neurological and physiological functions resulting from failed intracellular transport of cholesterol.
There are currently several therapies in Phase III of clinical development, two of which are targeted to the underlying pathology of NPC and another therapy, acetylleucine, that targets the neurological disease in a similar manner to miglustat. Although this will provide more efficacious treatment options for NPC patients, an unmet need remains for therapies that prevent the decline in neurological disease, and other musculoskeletal and physiological problems that occur, and significantly improve long-term outcomes. It remains likely that miglustat will be prescribed in addition to the novel therapies that are set to enter the market from 2026 onwards in order to improve overall therapeutic efficacy and prevent neurological disease.
Therapies with improved efficacy, low or minimal toxicities, ease of administration and reduced cost all remain largely unmet needs, as miglustat is often unable to prevent the long-term damage that occurs in many pediatric-onset and adult-onset patients and may only slow down disease progression. Furthermore, improvements in early diagnosis of NPC are critical to preventing some of the irreversible damage that occurs neurologically and physiologically, with most adults presenting with developing, irreversible neurological and psychiatric diseases, as well as physiological decline; and paediatric patients presenting with neurological disabilities, hepatosplenomegaly and physical disabilities.
Two cyclodextrin therapies, Mandos’ adrabetadex in Phase III and Cyclo Therapeutics’ (US) Trappsol Cyclo across the 3MM, have novel MOAs that are likely to reverse the decline in disability that arises in NPC as they target unesterified cholesterol trafficking within cells. This correction of the fundamental mechanism that leads to the complexity of neurological and physical disorders in NPC patients will potentially lead to improved long-term outcomes. Key opinion leaders (KOLs) interviewed by GlobalData have, however, reported a lack of enthusiasm for these novel therapies as the clinical data has only shown some mild efficacy, and the current clinical analysis for Adrabetadex is an attempt to salvage a therapy that has already failed previous Phase III trials.
There is another therapy in Phase III 3MM, acetylleucine, that targets the calcium channels that exist across the neuronal membrane and is designed to treat the onset of neurological disease that occurs as a result of NPC and other related disorders. NPC-related neurological disease leads to various cognitive and physical disabilities due to the accumulation of cholesterol in the neuronal cells. Acetylleucine is administered orally in a powdered solution three times a day and prevents the decline of neuronal cells due to irregularities in calcium uptake in the cells that contribute to that decline. This therapy addresses an unmet need in the NPC market, namely for therapies that directly have minimal toxicities and are easy to administer.