Y-mAbs Therapeutics has filed the first of the two antibody drugs it intends to submit to the FDA, starting with naxitamab for the treatment of neuroblastoma.
The Danish/US biotech is using the FDA’s rolling Biologics License Application (BLA) process to file naxitamab, an anti-GD2 antibody that has a breakthrough designation from the US regulator as a therapy for patients with neuroblastoma, a rare type of cancer that mostly affects babies and young children.
The BLA will cover the use of naxitamab in combination with GM-CSF – a white blood cell stimulating drug – in relapsed/refractory high-risk neuroblastoma patients. Rolling applications allow parts of the marketing application to be filed separately as they are completed.
Y-mAbs has previously said it also intended to file its radioimmunotherapy omburtamab in central nervous system/leptomeningeal metastasis before the end of December, but now says that will take place in the first quarter of 2020.
Omburtamab (previously burtomab) targets B7-H3, another cell surface antigen that has emerged as a promising target for cancer drugs.
The filing of naxitamab in neuroblastoma is a key milestone for the biotech and comes after a busy couple of years punctuated by a listing on the Nasdaq that raised $96m, and follow-up offering this year that brought in another $144m – funds that will be needed as it moves towards potentially having two approved products in 2020.
Y-mAbs reported new results from its main phase 3 naxitamab study at the International Society of Paediatric Oncology (SIOP) conference in October. This study focused on a subset of 28 patients with primary refractory high-risk neuroblastoma in October, who had been heavily pretreated with at least five earlier therapy rounds.
It showed a 78% overall response rate (ORR) with the drug, with a progression-free survival (PFS) rate of 50% at two years. Another subset of 30 patients with relapsed neuroblastoma resistant to salvage therapy had a 36% two-year OFS rate and an ORR of 37%. For the latter patient group, the threshold for FDA approval is 30% according to the company.
Naxitamab is also being developed in a phase 2 trial for osteosarcoma, a type of bone cancer, with a larger study due to get underway next year.
Speaking on Y-mAbs’ third-quarter results call last month, chief executive Claus Moller said that the biotech is hoping for FDA action dates for both its drug applications before the end of 2020.
He also said the delay to the omburtamab filing resulted from the FDA’s decision to change the format of a scheduled pre-BLA meeting to a general guidance meeting, setting back the process.
“We remain confident in the content of our pre-BLA meeting submission, and do not believe that this change in timing of the pre-BLA meeting with the FDA will impact our previously disclosed and anticipated timing for our complete omburtamab BLA submission,” he told analysts.