Kazia Therapeutics collars US FDA orphan drug designation for paxalisib in a highly aggressive childhood brain cancer

Kazia Therapeutics (ASX: KZA) has collared orphan drug designation (ODD) from the United States Food and Drug Administration for its lead candidate paxalisib in treating a rare and highly aggressive childhood brain cancer.

The ODD is specifically for paxalisib in treating atypical rhabdoid/teratoid tumours (AT/RT), and as part of the designation, the FDA will waive fees relating to a future regulatory filing in AT/RT.

Kazia noted this could potentially save the company U$3 million in FY2022 in filing fees for advancing paxalisib as a treatment for AT/RT.

“Childhood brain cancer has emerged as an important area of focus for the paxalisib program,” Kazia chief executive officer Dr James Garner explained.

“We have been working for some years with several world-leading researchers in diffuse intrinsic pontine glioma – one of the most aggressive childhood cancers.”

Dr Garner said recent data has shown the potential for paxalisib to benefit in AT/RT, which is another form of childhood brain cancer that is “poorly served” by existing treatments.

“This represents an important new opportunity for paxalisib, and one that we continue to explore enthusiastically with our collaborators and advisors,” he added.

Orphan drug designation

ODD from the FDA is granted to drugs that are considered promising treatments for rare “orphan” diseases. These orphan diseases are generally defined as less than 200,000 cases a year in the US.

If a company secures ODD, it can provide up to seven years of orphan drug exclusivity, in which competitors can’t use Kazia’s data to develop generic versions of paxalisib – effectively extending the life of a commercial product.

Kazia noted ODD also opens the door to opportunities for securing grant funding, protocol assistance and tax credits.

The company has already secured ODD for paxalisib in treating malignant glioma in adults, and diffuse intrinsic pontine glioma in children.

Advancing paxalisib

Paxalisib is part of a phase II trial sponsored by the Pacific Pediatric Neuro-Oncology Consortium (PNOC) into diffuse midline gliomas, which includes diffuse intrinsic pontine glioma.

The study combines several investigational new drug therapies and initial data is expected next year.

A phase I study of paxalisib in diffuse intrinsic pontine glioma is nearing completion with final data anticipated before the end of the year.