Antisense Therapeutics Ltd. has licensed its second-generation antisense inhibitor of CD49d in multiple sclerosis to Teva Pharmaceuticals in a deal that will net $2 million up front and possibly up to $100 million down the road.

In addition, Antisense, of Melbourne, Australia, is in line to receive royalties in the "low double-digit range" based on net sales of ATL1102. The agreement also provides an option for Teva to in-license ATL1102 as an aerosol drug for asthma.

Antisense, in turn, signed a separate deal with Isis Pharmaceuticals Inc., its Carlsbad, Calif.-based partner in ATL1102, turning over one-third of sublicense fees and milestone payments received from Teva, as well as a percentage of any royalties Antisense receives.

ATL1102 is a second-generation antisense inhibitor of CD49d, a subunit of VLA-4, and is currently in Phase IIa clinical trials as a treatment for MS.

The drug works by inhibiting VLA-4, preventing white blood cells from entering the sites of inflammation - such as the central nervous system in MS or the lung airways in asthma - thus halting the progression of the disease.

Under terms of the deal, Antisense will continue to manage and fund the current Phase IIa clinical trial in relapsing-remitting MS patients.

Completion of dosing, unblinding of the clinical trial and reporting the results are scheduled for the middle of this year. Jerusalem-based Teva would fund and perform all future development of ATL1102 beyond the current trial, if it decides to continue beyond that point.

If Antisense fails to meet a development milestone concerning completion of the current trial by an unspecified but agreed-upon date, Teva has the right to terminate the agreement and receive a $2 million termination fee.

It hasn't always been a smooth ride for ATL1102.

In 2005, Antisense temporarily halted a Phase II trial and convened an advisory group after Biogen Idec and Elan Corp. suspended marketing of their MS drug Tysabri (antibody to VLA-4) based on reports of two cases of a fatal disease that occurred following treatment with Tysabri in combination with Avonex (Interferon beta-1a). The panel eventually cleared the drug for further trials.

ATL1102 is the only Antisense drug in clinical trials, but it is doing toxicology studies on ATL1103, a second-generation antisense drug designed to block growth hormone receptor (GHr) expression, thus reducing levels of the hormone insulin-like growth factor-I (IGF-I) in the blood.

It is considered a potential treatment for diseases associated with excessive growth hormone action, including acromegaly, an abnormal growth disorder of organs, face, hands and feet, and diabetic retinopathy, a common disease of the eye and a major cause of blindness.

The company also has ATL1101 in prostate cancer. It also is an antisense inhibitor of IGF-Ir and has shown potent activity in laboratory studies, including in human cancer cells.