Recruitment problems scupper Bayer liver metastasis trial

Bayer has been forced to abandon a Phase III trial of its Stivarga drug in liver metastases after failing to recruit enough patients.

The COAST study was focusing on colorectal patients who were receiving surgical treatment for tumours that had spread to the liver, with Stivarga given as an adjuvant treatment and compared to placebo.

The aim was to prevent recurrence of liver metastases after 'curative' surgical treatment, with the main outcome measure in the trial disease-free survival over a 50-month follow-up period.

When colorectal cancer has spread to the liver, it takes on a new degree of severity; however, patients can still be cured if treated appropriately with surgery, radiotherapy or chemotherapy.

The enrolment target of 750 patients has not however been reached - despite "extensive measures to increase recruitment" - and COAST "will be halted before the study endpoints can be assessed," said Bayer.

Stivarga - a multi-kinase inhibitor that blocks several enzymes that promote cancer growth - ended 2014 with €224 million in sales, an increase of 17 percent on the prior year, although Bayer has suggested growth in the coming years will slow to "the mid-single-digit percentage range" unless it is approved in new indications.

"Importantly, this decision does not affect our commitment for Stivarga in the approved as well as potential additional indications," said Dr. Joerg Moeller, Bayer's head of global development.

Stivarga has been approved to treat colorectal cancer since 2012 and had its indication extended last year to include gastrointestinal stromal tumours (GIST). According to Bayer's most recent pipeline update, the drug is also in Phase III testing for liver cancer (hepatocellular carcinoma) and also in Phase II for other cancer types, as well as in an ophthalmic formulation for age-related macular degeneration (AMD).

It is among four late-stage compounds that Bayer has previously predicted could collectively add €5 billion to its revenues at peak. Analysts have agreed, albeit ahead of the latest trial news, suggesting it could eventually become a $1 billion-a-year brand.

A recently-published report from GlobalData predicted that Stivarga will become the leader in the Chinese market for colorectal cancer drugs, which in turn will become the third largest market for this type of therapy behind the US and Japan.