Ablynx files rare blood disorder drug, raising prospect of first commercial product next year

Around 7,000 to 8,000 people present with aTTP in North America, Europe and Japan each year.(Ablynx)

Belgian biotech Ablynx has filed its first-ever marketing application, seeking EU approval for its new drug for an ultrarare blood clotting disorder.

If approved, caplacizumab could be the first drug therapy for the condition—known as acquired thrombotic thrombocytopenic purpura (aTTP)—which results from an impaired blood clotting enzyme and causes very low blood platelet counts and the formation of microclots, leading to organ damage.

Caplacizumab stops that clot formation, says Ablynx, and if approved it would be the first alternative to plasma exchange therapy in patients with the disease, which has a 20% mortality rate per episode.  

The drug could be the first commercial product for Ablynx, which is one of Europe's top-tier biotechs, employing around 400 people and with eight programs in clinical trials. Ghent-based Ablynx estimates the annual market potential for caplacizumab to be around €800 million, and it is now targeting a possible launch for the drug in the first half of 2018, with a U.S. filing expected around the same time, according to CEO Edwin Moses.

The filing is based on phase 2 data from the TITAN trial, with a phase 3 trial called HERCULES running at the moment and due to generate results later this year. TITAN showed that caplacizumab treatment could reduce the time to platelet count normalization by around 40%, and it reduced recurrences while on drug treatment by around 74%.

Moses told delegates at the J.P. Morgan Healthcare Conference last month that he reckons that caplacizumab could grow into a €400-million-a-year product at peak, and the company thinks it can sell it on its own with a small sales force.  

Getting the drug filed will be a "huge step forward to us—all young biotechs aspire to taking a drug all the way through development and commercialize it themselves," he said.

Ablynx estimates that around 7,000 to 8,000 people present with aTTP in North America, Europe and Japan each year, with two-thirds being new diagnoses and one-third relapsed cases.

Ablynx focuses on "nanobodies," which are around one-tenth the size of a regular antibody, making them easier to administer, and can be linked together to hit multiple targets.

The pipeline includes inhaled treatment ALX-0171 for respiratory syncytial virus infections in midstage trials, and interleukin-6 (IL-6)-targeting nanobody rheumatoid arthritis candidate vobarilizumab.

AbbVie declined to pick up rights to vobarilizumab last October, possibly because there is already one IL-6 inhibitor on the market—Roche's Actemra (tocilizumab)—with new inhibitors from Sanofi/Regeneron and GlaxoSmithKline nearing the market and increasing competition from other drugs such as JAK inhibitors.

Moses said Ablynx would step up efforts to find another partner for the drug after end of phase 2 meetings with the FDA and EMA in Europe.