Biotech trust stock favourite Alnylam Pharmaceuticals (Nasdaq: ALNY) gained more than 16% yesterday after the presentation of ostensibly highly positive clinical trial data on one of its key competitors at a scientific meeting. Alnylam is held by several of the sector’s specialist investment trusts including Biotech Growth (BIOG, 3.6% of NAV) and BB Biotech (BBB, 3.6% of NAV) as well as Baillie Gifford-managed Edinburgh Worldwide (EWI,3.7% of NAV), a diversified non-biotech specialist with significant exposure to healthcare.
Pfizer yesterday disclosed detailed data from its Attr-act Phase III trial for Vyndaqel (tafamidis) for transthyretin cardiomyopathy – which was previously known only to be positive – at the European Society of Cardiology (ESC) Congress. The drug, which is already approved in the EU, is potentially a key competitor for Alnylam’s recently approved Onpattro (patisiran), which is indicated for polyneuropathy (but not specifically cardiomyopathy) in adults with hereditary transthyretin-mediated (hATTR) amyloidosis.
The study showed Vyndaqel reduced all-cause mortality by 30% (29.5% vs. 42.9%) and cardiovascular-related hospitalizations by 32% (0.48 vs 0.70 annualized rate), compared to placebo, both of which were statistically significant. The study data have been simultaneously published in the New England Journal of Medicine.
Pfizer plans to file Vindaquel for approval in ATTR cardiomyopathy and could receive approval in 2019.
Although Pfizer’s data were positive, Alnylam’s stock price rise seems to have come about as a result of the removal of an overhang that has existed since the study was first reported to be positive in March. Several factors, however, seem also to favour Alnylam’s competitive position, notably, the lack of any significant benefit for tafamidis in hereditary patients (this was unsurprising mechanistically, but had represented a potential threat), and the lack of dose response between the higher 80mg and the approved 20mg dose, another potential risk.
Alnylam, which is marketing Onpattro itself, is charging the equivalent of $450,000 per patient per year in the US – a figure which is not not unusual for a ultra rare disease – although this translates to about $345,000 per patient/year after rebates. Alnylam estimates that fewer than 3,000 patients are currently diagnosed with the rare condition in the US, but some 10-15,000 people have hATTR as most are undiagnosed.
Alnylam has a separate upcoming trial readout shortly in the form of the Envision Phase III study of givosiran in acute hepatic porphyrias, which is expected by the end of September.