AST-915 Study Results

Manhattan Pharmaceuticals, Inc. announced in mid-December 2010 encouraging results regarding
a study of AST-915 for the treatment of essential tremor. Data from this single dose study demonstrated that AST-915 was safe and well tolerated and demonstrated a clear effect on tremor power.

The study was conducted at The National Institute of Neurological Disorders and Stroke (NINDS)
at the National Institutes of Health (NIH) under a CRADA agreement between the NIH and Ariston
Pharmaceuticals, Inc., a wholly owned subsidiary of Manhattan Pharmaceuticals, Inc.

In this study, 18 subjects with essential tremor received single oral doses of AST-915. Researchers
measured the effect on tremor power to test the central tremor component at various time-points
after treatment. Safety, pharmacokinetic data and other efficacy measures were also evaluated.
AST-915 was well tolerated with non-serious adverse events being evenly distributed between active and placebo treatments.

Statistically significant reductions in tremor were evident after 80 minutes and up to 300 minutes,
the latest time-point measured following administration of AST-915. Further analysis also demonstrated
statistically significant lower tremor in favor of AST-915 compared to placebo.

“This early positive data in subjects with essential tremor clearly demonstrates human proof of concept
and indicates a need to explore the effect of higher doses and longer term administration of AST-915,”
said Malcolm Morville, PhD, Director of Manhattan Pharmaceuticals, Inc.

The NIH intends to submit an abstract to the 15th International Congress of Parkinson’s Disease and Movement Disorders taking place in Toronto, Ontario in June 2011. Complete study findings are expected to be disclosed at this and other scientific meetings, and by submission to scientific journals.

The International Essential Tremor Foundation (IETF) supported the early stages of the study by aiding the NIH in finding subjects. Through mailings and announcements in its publications, the Foundation devoted time and resources to increase awareness of the study among IETF members and the general public. Through these efforts, the NIH was able to find qualified people to participate in the study.