Three-hundred Canadian women will face a pharmaceutical giant arguing the company never disclosed the risks associated with their hormone therapy.

They hope more women in Atlantic Canada will join their class action lawsuit against Pfizer.

Between 1977 and 2003, all of the women were prescribed Premplus, or Premarin in combination with progestin, to treat symptoms of menopause.

All of the 300 women were later diagnosed with breast cancer.

Douglas Lennox, a lawyer for Klein Lyons.

Douglas Lennox, a lawyer for Klein Lyons, says based on statistics they believe drug was responsible for as many as 12,000 cancer cases in Canada. (CBC)

A lawyer representing the women says it was announced in 2002 that those drugs caused breast cancer. 

“The complaint that our clients have is that the drug company knew or ought to have known many years before that and they should have given Canadians a proper warning,”  said Doug Lennox, a lawyer for Klein Lyons.

The drug Premplus was made by Wyeth Pharmaceuticals, now owned by Pfizer, one of the world's biggest drug companies.

Atlantic women sought to join class action lawsuit

Lawyers of the women believe there are more victims in this province but time is running out to join the case.

“We think  based on statistical information on the Canadian Cancer Registry that this drug was responsible for as many as 12,000 cancer cases in Canada and as many as a thousand in Atlantic Canada,” said Lennox.

But only nine women from the region have registered and the deadline to opt in is Aug. 25. 

In the U.S. Pfizer settled and paid more than a billion dollars to close to 10,000 women who had taken these drugs and suffered because of it. 

The lawyers at Klein Lyons don't see why it should be different in Canada.

For women going through menopause now, hormone replacement therapy has changed dramatically.

“In the past, the hormones were more synthetic hormones and today there are more hormones that are closer to our natural bodies hormones,” said pharmacist Anastasia Hanias.

She says women now have access to bio-identical hormones, patches and cream, less invasive treatments and natural options.