Isis Pharmaceuticals, Inc. has earned a $1.5 million milestone payment from Biogen Idec related to the advancement of the ongoing phase II study of ISIS-SMNRx in infants with spinal muscular atrophy (SMA).

The phase II study of ISIS-SMNRx is an open-label, multiple-dose, dose-escalation pilot study in infants who have been diagnosed with Type I SMA. To meet enrollment criteria, infants must be between the ages of three weeks and seven months, live in close proximity to a study site and pass screening evaluations conducted at study sites. The study is being conducted at centers in the United States and Canada.

ISIS-SMNRx is an investigational compound designed to alter the splicing of a closely related gene (SMN2) to increase production of fully functional SMN protein. The United States Food and Drug Administration granted orphan drug status and fast track designation to ISIS-SMNRx for the treatment of patients with SMA. Isis is currently in collaboration with Biogen Idec to develop and potentially commercialize the ISIS-SMNRx to treat all types of SMA. Under the terms of the January 2012 agreement, Isis is responsible for global development and Biogen Idec has the option to license the compound until completion of the first successful phase II/III study. ISIS-SMNRx is currently being evaluated in two phase Ib/IIa multiple-dose, dose-escalation studies. The first is in children with Type II or Type III SMA. The second is in infants with Type I SMA.

Isis acknowledges support from the following organizations for ISIS-SMNRx: Muscular Dystrophy Association, SMA Foundation, Families of SMA and intellectual property licensed from Cold Spring Harbor Laboratory and the University of Massachusetts Medical School.

SMA is a severe genetic disease and is caused by a loss of, or defect in, the survival motor neuron 1 (SMN1) gene leading to a decrease in the survival motor neuron (SMN) protein. SMN is critical to the health and survival of nerve cells in the spinal cord responsible for neuromuscular growth and function.

Isis is exploiting its leadership position in antisense technology to discover and develop novel drugs for its product pipeline and for its partners.