Alnylam Pharmaceuticals Inc. ( ALNY - Analyst Report ) recently announced that its candidate ALN-TTR02 has fared well in a phase I study (n=17). The candidate is being developed for the treatment of transthyretin (TTR)-mediated amyloidosis (ATTR). The data was presented at a seminar in Boston University School of Medicine.

The randomized, single-blind, placebo-controlled and single-ascending dose study assessed the safety and tolerability profile of ALN-TTR02. The candidate was found to be safe and well tolerated with an impressive pharmacologic profile. Results from the study revealed that patients treated with ALN-TTR02 experienced reduction of up to 94% of serum TTR following a solitary dose.

We remind investors that last month the US Food and Drug Administration (FDA) granted orphan drug status to ALN-TTR02. The candidate, ALN-TTR02, received orphan drug status to treat patients suffering from familial amyloidotic polyneuropathy (FAP). The disorder refers to one of the predominant clinical manifestations of TTR- ATTR.

We note that the orphan drug designation is granted in the US only to drugs that treat a disease affecting less than 200,000 people in the country. Moreover, the orphan drug status for ALN-TTR02 provides Alnylam with seven years of marketing exclusivity (from the day ALN-TTR02 is cleared by the FDA) in the US for the indication.

The company also initiated a phase II trial to evaluate clinical activity, safety and tolerability of multiple once-monthly doses of ALN-TTR02 in patients suffering from ATTR. Subject to positive results, the company plans to initiate pivotal trial in 2013.

Apart from Alnylam, Pfizer ( PFE - Analyst Report ) is also developing its candidate, Vyndaqel (tafamidis), to treat TTR-FAP. We note that TTR-FAP received a complete response letter (CRL) from the FDA in June 2012. The drug is approved in the EU.

Apart from ALN-TTR02, Alnylam is also developing ALN-TTRsc, for the utilization of GalNAc-conjugate delivery technology and subcutaneous dose administration, into clinical development. The company intends to file a New Drug Application (IND) for ALN-TTRsc in the second half of 2012 with data expected in the first half of 2013. Furthermore, the company is developing ALN-RSV01 for the treatment of respiratory syncytial virus infection; ALN-VSP for the treatment of liver cancer.