Sutts, Strosberg LLP and Siskinds LLP announced they intend to commence a class-action lawsuit on behalf of all cancer patients who received incorrect doses of chemotherapy medications, cyclophosphamide and gemcitabine, between Jan. 1, 2012 and March 28, 2013.

Four Ontario hospitals are informing 990 patients that they received lower than intended doses of cyclophosphamide and gemcitabine, according to a statement from Cancer Care Ontario. It impacted 665 patients in London, 290 in Windsor, 34 in Oshawa and one in Peterborough. Patients at one New Brunswick hospital were also affected.

The law firms say the defendant in the lawsuit will be the pharmaceutical company which prepared and supplied the drugs.

The Ministry of Health has confirmed the pharmaceutical company Marchese Hospital Solutions supplies the drugs to these locations.

Marchese Hospital Solutions issued a statement on Wednesday, saying: "We are confident that we fully met all of the contract requirements including both volume and concentrations for these solutions.  However, we share responsibility to ensure that patients and their families are not given any reason for concern about their treatment. We take this responsibility very seriously."

Windsor Regional Hospital CEO David Musyj told CTV News on Wednesday morning, he wasn't aware of the lawsuit.

“If people need to address their issues in that way I don’t blame them whatsoever,” says Musyj. “If I was a family member or a patient impacted by this, I would get past the point of information gathering and get angry, because I can tell you as a part of our emotion, part of it is anger as a staff as well.”

The affected patients received a letter explaining that they received incorrect doses of their chemotherapy medication. Hospital officials say 17 of the 290 Windsor patients have passed away.

Tracee Bridgen is battling non-hodgkins lymphoma. After returning home from an appointment at Windsor Regional Hospital Tuesday, she found the letter.

“My head was spinning. I actually didn't know what to think,” says Bridgen."I was today for an ultrasound to see if my cancer is back. I came home to this letter, I am definitely worried."

Bridgen says it’s a feeling not everyone could understand.

“It's affected people in ways that you don't even know unless you're a cancer patient, to be honest," says Bridgen.

Hospitals have stopped getting the drugs from the supplier and like Windsor Regional, officials at London Health Sciences Centre have taken matters into their own hands.

“Instead of having a company actually do the compounding or the preparation like that, we've got the source materials from drug manufacturers, and we've brought all that production into our own hospital pharmacies," says Neil Johnson, vice president of the Southwest Cancer Program, LHSC.

Cancer Care Ontario officials say they were advised on March 27 that there was an error in the doses of cyclophosphamide which they received over the past year.

In the compounded process, the pharmaceutical company did not adjust for the overfill present in IV bags and as a result the products are of a lower concentration than labelled, according to Musyj. This resulted in a three to 13 per cent lower dosage being administered to the 990 patients, starting in February 2012.

"What you're supposed to do, because these bags are overfilled, is you're supposed to extract all of the saline solution from them or start with an empty bag," says Musyj.