AstraZeneca, along with Merck & Co, announced on Thursday that the US Food and Drug Administration has granted Orphan Drug Designation (ODD) for selumetinib, a MEK 1/2 inhibitor, for the treatment of neurofibromatosis type 1 (NF1).
The FTSE 100 drugmaker described NF1 as an incurable genetic condition, which affects one in 3,000 births with highly-variable symptoms, including cutaneous, neurological and orthopaedic manifestations.

It said NF1 could cause secondary complications including learning difficulties, visual impairment, pain, disfigurement, twisting and curvature of the spine, high blood pressure and epilepsy.

Plexiform neurofibromas are a neurological manifestation of NF1, the AstraZeneca board explained, and arose from nerve fascicles that tend to grow along the length of the nerve.

PNs occurred in between 20% and 50% of NF1 patients causing pain, motor dysfunction and disfigurement.

“Neurofibromatosis type 1 is a devastating condition that can lead to life-threatening complications,” said AstraZeneca executive vice-president of global medicines development and chief medical officer Sean Bohen.

“There is no known cure for neurofibromatosis and there are limited treatment options to manage symptoms.”

The potential benefit of selumetinib in NF1 was being explored in the US National Cancer Institute-sponsored Phase I/II SPRINT trial in paediatric patients with symptomatic NF1-related PNs, with Phase II trial results expected later in 2018.

AstraZeneca said the FDA's ODD programme provided orphan status to medicines that were 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 US.

In addition to NF1, selumetinib was being investigated in the Phase III ASTRA trial of patients who are diagnosed with differentiated thyroid cancer following surgery and treatment with radioactive iodine.

Selumetinib was granted ODD by the US FDA for the adjuvant treatment of stage III/IV differentiated thyroid cancer in 2016.

It was also being explored as a monotherapy and in combination with other treatments in Phase I trials.

“We're looking forward to working with our colleagues at AstraZeneca to develop selumetinib and understand how it may benefit patients with NF1,” commented Roy Baynes, senior vice president and head of global clinical development, and chief medical officer, at Merck's MSD Research Laboratories.