Pfizer signs biomarker deal for personalised lung cancer drug

Pfizer has signed a three-way deal with Roche subsidiary Ventana Medical Systems and Cell Signalling Technology to develop a companion diagnostic for its recently-approved lung cancer drug Xalkori.

Xalkori (crizotinib) is a dual inhibitor of two receptor tyrosine kinases - ALK (anaplastic lymphoma kinase) and c-Met - and was approved in the US for the treatment of non-small cell lung cancer (NSCLC) in August 2011.

It is either in phase III testing or awaiting registration in the EU and other countries around the world.

Ventana will develop a companion diagnostic that will look for ALK gene rearrangements in NSCLC patients and help select patients for treatment with Pfizer's drug. The immunohistochemistry-based test will make use of antibody technology developed by CST.

The US approval of Xalkori was based on the results of two single-arm studies enrolling a total of 255 patients with late-stage ALK-positive NSCLC, most of whom had received prior chemotherapy. In the studies, the objective response rates were 50 per cent and 61 per cent, respectively.

Xalkori is has been a leader in the pharma industry's personalised or stratified medicine development programmes, with a companion diagnostic was co-developed with the drug from the early stages of development.

The initial approval was granted based on the use of a fluorescence in situ hybridisation (FISH) assay developed by Abbott Molecular, but the deal with Ventana and CST will provide an easier option for routine patient testing.

The original FISH assay can be technically challenging and costly, according to a recent review paper in the Journal of the National Comprehensive Cancer Network (December 1, 2011).

It has been suggested that large-scale screening of patients with NSCLC, as recommended by NCCN, may require development and validation of alternative screening strategies, such as a combination of IHC and FISH.

Between 1 per cent and 7 per cent of NSCLC patients are thought to carry the ALK gene rearrangement, and this type of lung cancer is typically seen in non-smokers.

Analysts have suggested that Xalkori could achieve peak sales of $2.5bn at peak, thanks to a hefty price tag of more almost $10,000 a month.  Given the cost, effective screening is clearly required to make sure the drug is used in the appropriate patients.