AstraZeneca and MSD have announced that the US Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation (BTD) for the MEK 1/2 inhibitor and potential new medicine selumetinib.

This designation is for the treatment of paediatric patients aged three years and older with neurofibromatosis type 1 (NF1) symptomatic and/or progressive, inoperable plexiform neurofibromas (PN), a rare, incurable genetic condition.

SPRINT trial

The BTD is based on Phase II data from the SPRINT trial, testing selumetinib as an oral monotherapy in paediatric patients, aged three years or older with inoperable NF1-related PN.

“Selumetinib shows promise in the treatment of NF1-related plexiform neurofibromas, a rare and debilitating disease with no approved medications to date. The Breakthrough Therapy Designation acknowledges the significant unmet need of these patients and the potential benefit of selumetinib in this setting,” says José Baselga, Executive Vice President, Research and Development, Oncology, AstraZeneca.

Ninth BTD

This is the ninth BTD that AstraZeneca has received from the FDA since 2014. Selumetinib was granted Orphan Drug Designation for the treatment of NF1 by the US FDA in February 2018 and the European Medicines Agency in August 2018.

Selumetinib

Selumetinib is a MEK 1/2 inhibitor and potential new medicine licensed by AstraZeneca from Array BioPharma Inc. in 2003. AstraZeneca and MSD entered a co-development and co-commercialisation agreement for selumetinib in 2017.

The NF1 gene provides instructions for making a protein called neurofibromin, which negatively regulates the RAS/MAPK pathway, helping to control cell growth, differentiation and survival. Mutations in the NF1 gene may result in dysregulations in RAS/RAF/MEK/ERK signalling, which can cause cells to grow, divide and copy themselves in an uncontrolled manner, and may result in tumour growth. Selumetinib inhibits the MEK enzyme in this pathway, potentially leading to inhibition of tumour growth.

Selumetinib is being assessed as a monotherapy and in combination with other treatments in ongoing trials.

Photo of José Baselga: Juliana Thomas, Memorial Sloan Kettering Cancer Center, Wikipedia