GlaxoSmithKline's foray into rare disorders is continuing with an agreement signed with Amicus Therapeutics to develop and market the latter's investigational Fabry disease drug Amigal.

Under the terms of the agreement, GSK is paying an upfront licence fee of $30 million and is paying out another $30 million or so for a 19.9% stake in Amicus. The New Jersey-based firm is eligible to receive up to $170 million in milestone payments, and royalties on future sales.

The new partners say they will jointly fund development costs associated with Amigal  (migalastat) which is currently in Phase III trials for Fabry disease (preliminary results expected in the second half of 2011), a rare inherited lysosomal storage disorder. GSK and Amicus said they also intend to advance clinical studies exploring the co-administration of migalastat with enzyme replacement therapy for the treatment of the disease.

Marc Dunoyer, head of GSK Rare Diseases, said the "collaboration is another significant milestone in delivering our vision" for the new unit which was established in February. He added that Amicus' scientific and clinical expertise in human genetic diseases "is among the best in the industry, and we are pleased to be collaborators and investors in this exceptional company”.

Mr Dunoyer added that "it is our hope to deliver a first-in-class, oral medicine to the thousands of people worldwide living with this devastating rare disease”. The two leading treatments for Fabry's disease are Genzyme Corp's Fabrazyme (agalsidase beta), which has being suffering supply problems,  and Shire's Replagal (agalsidase alfa).

Amicus actually signed a pact with Shire in November 2007 covering Amigal and two other rare disorder treatments - Plicera (isofagomine) for Gaucher disease and AT2220 (deoxynojirimycin) for Pompe disease. However the pact was mutually terminated in October last year and the rights were returned to Amicus.

The deal comes ten days after GSK said its aim is to have a list of around 200 priority rare diseases and signed a collaboration with Italy's Fondazione Telethon and Fondazione San Raffaele  for  an investigational gene therapy for ADA severe combined immune deficiency which affects just 350 children worldwide.

Japan approves two GSK drugs

Meantime, GSK has also announced that it has received approval in Japan from the Ministry of Health, Labour and Welfare for Revolade (eltrombopag), known as Promacta in the USA, for the treatment of chronic idiopathic thrombocytopenic purpura (ITP), and for Xyzal (levocetirizine), the first new antihistamine to be made available in the country for eight years.

Xyzal has been approved for the treatment of allergic rhinitis, urticaria, eczema and dermatitis, prurigo and cutaneous pruritus in patients over the age of seven years. GSK acquired the rights to the drug for a number of Asian Pacific, African and Latin American countries, as well as the Middle East, from UCB in January 2009.