The US Food and Drug Administration (FDA) has granted orphan-drug designation to biopharmaceutical company MediciNova Inc.'s MN-166 (ibudilast) for treatment of Krabbe disease.  

MediciNova previously opened an Investigational New Drug (IND) application with the Division of Neurology Products (DNP) for MN-166 (ibudilast).

Yuichi Iwaki, MD, PhD, president and chief executive officer of MediciNova, Inc., said "We are very pleased to receive orphan-drug designation for MN-166 for Krabbe disease, a rare disease for which hematopoietic stem cell transplantation, the only currently available treatment option, is not without potential risk to the patient and is limited in efficacy. As we already have an open IND, we plan to finalise a protocol and submit it to FDA in order to conduct a clinical trial of MN-166 in Krabbe disease."

Krabbe disease is a rare genetic degenerative disorder for which there is no cure and is generally fatal before two years of age. Krabbe disease has 4 clinical subtypes (types 1 - 4), distinguished by age of onset. In the vast majority of cases, the symptoms of Krabbe disease begin at age 0-6 months (type 1 early infantile form). Initial signs and symptoms typically include irritability (e.g., excessive crying), limb spasticity, absent reflexes, muscle weakness, feeding difficulties, episodes of fever with no sign of infection, stiff posture, and slowed or regressed neurocognitive development. As the disease progresses, muscles continue to weaken, affecting the infant's ability to move, chew, swallow, and breathe. Affected infants also experience vision loss and seizures, regress rapidly to a decerebrate condition and usually succumb to the disease before their second birthday. Approximately 10 per cent present symptoms later in life, including in adulthood (types 2 - 4). Progressive loss of vision, difficulty walking, decline in thinking skills, loss of manual dexterity, and muscle weakness are the most common initial symptoms in this form of the disorder, however, signs and symptoms vary considerably among affected individuals. Patients with late-onset Krabbe disease regress at a slower pace and have the potential to live significantly longer than patients diagnosed in early infancy.

Drugs that receive orphan-drug designation from FDA are entitled to seven years of marketing exclusivity if they are approved by the FDA for the same rare disease. The orphan drug designation programme provides orphan status to drugs and biologics which are defined as those intended for the safe and effective treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000 people in the U.S., or that affect more than 200,000 persons but are not expected to recover the costs of developing and marketing a treatment drug.

MN-166 (ibudilast) has been marketed in Japan and Korea since 1989 to treat post-stroke complications and bronchial asthma. MediciNova licensed MN-166 (ibudilast) from Kyorin Pharmaceutical Company Ltd. for potential utility in relapse-remitting multiple sclerosis (RRMS). Intellectual property was additionally established or obtained by MediciNova in progressive MS and other neurological conditions.

MN-166 (ibudilast) is a first-in-class, orally bioavailable, small molecule phosphodiesterase (PDE) -4 and -10 inhibitor and a macrophage migration inhibitory factor (MIF) inhibitor that suppresses pro-inflammatory cytokines and promotes neurotrophic factors. It attenuates activated glia cells, which play a major role in certain neurological conditions. Ibudilast's anti-neuroinflammatory and neuroprotective actions have been demonstrated in preclinical and clinical study results and provide the rationale for its therapeutic utility in neurodegenerative diseases (e.g., progressive MS and amyotrophic lateral sclerosis (ALS)), substance abuse/addiction and chronic neuropathic pain.