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Amarantus receives orphan designation for its anti-apoptotic drug (MANF) for the treatment of retinitis pigmentosa

Amarantus Bioscience Holdings Inc., (AMBS), based in San Francisco, California, has announced that the FDA has granted orphan drug designation for the company’s investigational drug, MANF (mesencephalic-astrocyte-derived neurotrophic factor), for the treatment of retinitis pigmentosa (RP).   According to the company, MANF is a naturally-occurring protein that reduces and prevents apoptosis in response to injury or disease. The company said that pre-clinical data demonstrated that MANF provided “protective functional effects in an animal model of RP” and that “toxicology studies have demonstrated that MANF was well-tolerated following a single intravitreal administration of a therapeutically relevant dose”.


The MANF protein is understood to have potential in the treatment of retinitis pigmentosa, AMD and glaucoma and is also in preclinical testing for Parkinson’s disease and traumatic brain injury. Amarantus licensed the opportunity from the Bascom Palmer Eye Institute following an exclusive option struck in 2013 between the parties. MANF is understood to have broad medicinal potential as it is “produced by the body for the purpose of reducing and preventing apoptosis (cell death) in response to injury or disease, via the unfolded protein response (UFR) of the endoplasmic reticulum”. While MANF’s current lead indication is retinitis pigmentosa, other targets for include Parkinson’s disease, Alzheimer’s disease, Wolfram’s Syndrome, traumatic brain injury (TBI), myocardial infarction, antibiotic-induced ototoxicity and other rare orphan diseases.


According to the company, MANF has shown positive 15-day non-GLP ocular toxicology data for a single intravitreal administration in an ocular safety animal model. The safety study evaluated the ocular tolerance of MANF after a single intravitreal administration in pigmented rabbits over a 15 day period at dosing levels expected to be higher than therapeutically relevant dosing levels in human. The company reported “no treatment or administration-related effects on body weight, clinical observations or ophthalmic examinations and no pathological findings related to treatment were found in any of the eyes observed during histopathology evaluation”. The report from the study concluded that a single intravitreal administration of MANF was macroscopically and microscopically very well tolerated.


Commenting on the orphan approval, President & CEO of Amarantus, Mr. Commissiong stated, “We are very pleased to receive orphan drug designation for MANF in RP. This represents an important milestone for the company as well as a significant step forward for our clinical and regulatory strategy. Our goal is to continue to identify ways to build value into our MANF program and advance this promising product candidate in multiple therapeutic areas with significant unmet need.”