Pfizer has filed its much-touted oncology agent crizotinib with regulators in the USA and Japan.

The drugs giant says that its New Drug Application for crizotinib, an oral first-in-class anaplastic lymphoma kinase (ALK) inhibitor, has been accepted for filing and granted priority review status by the US Food and Drug Administration. It has also been submitted to the Japanese Ministry of Health, Labour and Welfare and the proposed indication is for the treatment of patients with ALK-positive advanced non-small cell lung cancer.

Crizotinib received orphan drug designation from the FDA in September last year and was granted fast-track status in December, which meant that Pfizer could initiate a rolling submission. In Japan, the firm commenced crizotinib clinical trials for patients with ALK-positive advanced NSCLC in March 2010, and it was awarded orphan drug status there in January.

The drug caused a stir when a Phase I trial demonstrated that 57% of patients had their tumours reduced, and at eight weeks of the treatment, 87% showed disease stabilisation. There will be some preliminary data from the Phase II study of crizotinib presented for the first time at next month's American Society of Clinical Oncology meeting.

Filed three years after trials started

Garry Nicholson, head of Pfizer's oncology business unit, said that "our ability to file applications for regulatory review in the USA and Japan simultaneously only three years after beginning worldwide clinical trials in patients with ALK-positive lung cancer is a testament to the hard work of the crizotinib team and the productive discussions that we have had with the respective regulatory agencies". He added that given the data seen to date, the drug "may change the treatment paradigm for patients with ALK-positive advanced NSCLC".

Pfizer is working (non-exclusively) in collaboration with Abbott Molecular on a commercial standardised FISH (fluorescent in situ hybridisation) test to validate ALK-positive tumours. Approximately 3%-5% of NSCLC patients have tumours that are positive for the ALK fusion gene.