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Ontario's Health Ministry says it will start requiring colorectal cancer patients to take a new test that can determine whether the drug it purchases for them in the United States actually works.
However, it did not provide details on Wednesday on when those patients will be required to undergo the test for the K-ras gene that can weed out 40 per cent of patients for whom the drug cetuximab, known by the trade name Erbitux, is useless.
“The ministry does intend to require K-ras testing before receiving Erbitux,” Health Ministry spokesman Mark Nesbitt said Wednesday.
Meanwhile, the Ontario government continues to send cancer patients to U.S. hospitals, where they receive cetuximab, one of the world's most expensive cancer drugs.
The drug is typically used on patients for whom other treatments have failed or who have become resistant to other drugs. It shrinks tumours and delays tumour growth in some patients, especially when used in combination treatment.
Only recently has research revealed that the test – not yet commercially available in Canada – can discern those 60 per cent of colorectal cancer patients who have the wild-type version of the K-ras gene and would potentially benefit from cetuximab. For the remaining 40 per cent with a K-ras mutation, the drug is ineffective.
At issue is funding for the test that one pathologist estimated would cost about $500. Mount Sinai Hospital in Toronto says it will be able to perform the K-ras test – to the international standards required – starting in mid-July. The University Health Network, also in Toronto, also says it can do the test.
Despite the lack of available testing in Canada, some medical oncologists are sending tumour samples to U.S. laboratories, where patients can learn in as little as eight days whether cetuximab would be of potential benefit.
One of them, Tony Gumpert of Ottawa, paid $316.40 (U.S.) for the test, done in New York. When he learned he had the mutated K-ras gene, he turned down eight weeks of approved Ontario government funding of cetuximab treatment, to be done at a U.S. hospital at a cost of $92,761.94 (U.S.). He has since sent the province a bill for the test.
Ontario provides the broadest coverage of cetuximab, having sent eligible colorectal cancer patients to U.S. cancer hospitals for more than three years. It spent $32-million for 418 patients to have the infusions alone or in combination with the chemotherapy drug Irinotecan, from fiscal 2005-2006 to June 9, according to Mr. Nesbitt.
Elsewhere, access is less straightforward. Some obtain it on a case-by-case basis or through private insurance.
Across Canada, the drug has been released 508 times since 2005 under the federal Special Access Program, with requests from all provinces except Manitoba, according to figures provided June 19 by Health Canada.
Barry Stein, president of the Colorectal Cancer Association of Canada, said testing for the K-ras gene is an important step.
“If you are mutated K-ras, one wouldn't want to take these products because of the potential negative effects,” said Mr. Stein, noting that the test also works on another drug, panitumumab, which recently received a conditional notice of compliance from Health Canada.
