A collaboration between Sanofi’s Genzyme unit and Alnylam’s set up in 2014 has borne its first fruit, with Genzyme opting into a drug candidate for haemophilia.
The drug – called ALN-AT3 – is an RNA interference (RNAi) drug that works via a process known as gene silencing, switching off the function of an endogenous protein called antithrombin (AT). The drug, which is administered by subcutaneous injection once a month, is currently being tested in a phase I trial in patients with moderate-to-severe haemophilia.
Interim results from that trial – reported in June – showed that ALN-AT3 was able to reduce the activity of AT by up to 86% which was associated with a significant increase in the activity of thrombin, which is an integral part of the clotting process, as well as a reduction in bleeding frequency.
The effects lasted over two months after the last dose was administered and – on the strength of the results – Alnylam said it intends to advance ALN-AT3 directly to a phase III trial in mid-2016.
Genzyme chief executive David Meeker said that the company had decided to exercise its option on the strength of this phase I data, adding that ALN-AT3 “represents a unique and promising new approach for the potential treatment of haemophilia.”
ALN-AT3 is the first opt-in since the 2014 rare disease alliance was formed, but the third opt-in overall as Genzyme has previously taken licenses to revusiran and patisiran, which are both in trials for amyloidosis. Genzyme and Alnylam have been working together since 2012.
Under the terms of the alliance, Alnylam retains product rights in North America and Western Europe, while Genzyme gets rights to certain programmes in Alnylam’s genetic medicines pipeline in the rest of the world.
Genzyme will fund 20% of the global development costs of ALN-AT3 beginning at the start of next year.
Commenting on the project during Alnylam’s second-quarter results briefing, chief medical officer Akshay Vaishnaw said: “Our ALN-AT3 programme is gaining increasing recognition as a potentially transformative approach for haemophilia.”
If it proves effective in late-stage trials, ALN-AT3 could have a dramatic impact on haemophiliac patients who develop inhibitory antibodies against standard therapy with blood-clotting factors VIII and IX. Around 5% of haemophilia B patients and 30% of those with haemophilia A fall into this category.
Additional data from the phase I study will be reported later this year, most likely at the American Heart Association (AHA) in December.