08/05/2011 02:50 EDT | Updated 10/05/2011 05:12 EDT

Class-action lawsuit linking drug to breast cancer can go ahead: B.C. judge

VANCOUVER - A major drug company has lost its effort to derail a Canadian class-action lawsuit linking two of its hormone replacement drugs to higher rates of breast cancer.

A B.C. Supreme Court judge ruled that the class action can be certified and women from British Columbia and other provinces can be represented in their efforts to get compensation.

A lawyer for the drug maker, Wyeth Canada, which has been bought by drug company Pfizer, had argued there were too many individual circumstances among claimants and lumping them together into a class-action case would be unwieldy.

But Justice Miriam Gropper disagreed.

"In spite of there being a number of individual issues, there will be substantial benefits with respect to access to justice and judicial economy achieved through a common issues trial," she wrote.

"Individual litigation would not be economically viable for most of the class members and a class proceeding is the most effective means of providing access to justice."

Efforts to launch the class-action suit began in 2006. David Klein, a lawyer representing the women, said he expects the claimants to eventually include thousands of women who took the drugs between 1977 and 2003.

The women claim they got breast cancer after taking the medications to ease symptoms of menopause, such as hot flashes and night sweats.

But a major study published in 2002 linked the drugs to higher rates of heart attack, stroke and cancer in some cases.

Dianna Stanway, of Sechelt, B.C., is the central claimant in the case. She claims she took one of the drugs for seven years but became concerned after hearing the reports linking it to breast cancer.

Two months after she quit using the drug, she was diagnosed with breast cancer.

Stanway's lawyers argue Wyeth-Ayerst International and its Canadian subsidiary acted negligently because they did not warn doctors and patients that the hormone replacement drugs Premarin and Premplus might be dangerous.

Little or no testing on the efficacy or safety of the drugs was done by the drug manufacturer, the court documents claim.

"The defendants repeatedly and actively portrayed these drugs as being effective at providing a host of health benefits even though research to support such claims was limited or non-existent or suggested otherwise," the claim said.

None of the accusations have been proven in court.

In a statement, Pfizer said hormone therapy remains an "important treatment option" for women suffering severe side effects of menopause.

"This procedural ruling is not a decision on the merits of the case, which the plaintiff ultimately must prove at trial," the company said.

"The company will vigorously defend this case, which still faces procedural challenges before it can go to trial."

The statement did not clarify whether that means Pfizer will appeal Gropper's Thursday ruling and a company spokesman declined further comment.

The company maintains it acted responsibly by conducting more than 180 studies on hormone therapy's benefits and risks and that the labels on the medication accurately portray those.

"It is widely accepted that science cannot determine what caused or contributed to any individual woman's breast cancer except in rare circumstances where genetics play a role."

However, the lawsuit argues that the 2002 Women's Health Initiative Study by the United States National Institutes of Health concluded there was a connection between hormone therapy and an increase in breast cancer.

After the study, use of the therapy plummeted and so did breast cancer rates, Klein said.

Klein noted the company has been sued on similar grounds in the United States, leading to settlements in more than 3,300 cases.

Pfizer recently set aside $772 million to resolve the remaining claims, he noted.