More than 1,100 cancer patients in Ontario and New Brunswick received weaker-than-prescribed doses of the drugs, which were prepared by the same supplier, Marchese Hospital Solutions. Some were taking the diluted drugs for more than year.
There was too much saline added to the bags containing cyclophosphamide and gemcitabine, in effect watering down the prescribed drug concentrations by three per cent to 20 per cent.
But Marchese, which prepared the drugs for five hospitals, appears to fall into a jurisdictional grey area.
Preparing medications for hospitals — which they would usually do themselves — is a relatively new business model, said Dr. Supriya Sharma, senior medical adviser at Health Canada.
"If the activities that they were doing were done under a hospital setting, that usually falls under provincial supervision," she said in an interview.
"But because this is a new business model, we need to take a look at it to get a different approach to see what jurisdiction it falls under."
Health Canada and the Ontario College of Pharmacists — which oversees pharmacists and their work — are looking at what Marchese is doing to sort out which of the various regulations should apply to their operations, Sharma said.
"It does get a bit complex because under one roof with the operations, they actually have different areas that are doing different activities, and those different activities may actually be under different jurisdictions," she said.
Health Canada regulates and inspects drug manufacturers, while the college is responsible for pharmacists in Ontario. Hospitals are responsible for the purchase and security of their drugs.
Marchese Hospital Solutions is technically not a pharmacy, which means it doesn't fall under the oversight of the provincial government or the college.
However, the college is responsible for pharmacists and technicians, including those who may have been working independently for the company.
Marchese has a pharmacy in Hamilton, Ont., which was inspected by the college in January. Sharma said Health Canada had not visited any of Marchese's businesses before the diluted drugs came to light, but paid a short visit after.
The college isn't releasing its report, saying their bylaws currently prohibit its disclosure. However, a spokeswoman for the college said they have been reviewing those bylaws.
The question of who's responsible for overseeing Marchese's operations is complex, Ontario Health Minister Deb Matthews acknowledged.
"There is collective responsibility, but there is lack of clarity over who has ultimate authority," she said.
But patients should not be caught up in a turf war, Matthews added. She'll give the college "all the tools they need" to get answers.
"I have no patience for jurisdictional squabbles over who has responsibility," she said.
Outsourcing of medication preparation is a new trend and now's the time to start looking at how it should be done in Canada, said Sylvia Hyland, chief operating officer of the Institute for Safe Medication Practices Canada.
"Our environment is changing, technology's changed, decisions change on how we best bring medications to our patients," she said.
"So it's possible that we need to make sure that oversight and regulations are up to date."
But Ontario's opposition parties say it's too late for the affected patients, who ended up falling through the jurisdictional cracks.
Premier Kathleen Wynne defended her government's response to the drug scare, saying they've appointed a pharmacy expert, Jake Thiessen, to review Ontario's cancer drug system.
"We need to get to the bottom of this," she said. "We absolutely need to talk to everyone who is an expert in the field who understands how this should work."
Thiessen, the founding director of the University of Waterloo's School of Pharmacy, has previously advised both the Ontario and federal governments.
Matthews said he'll be assisted by a working group that includes people from the affected hospitals, the college, Health Canada, Cancer Care Ontario and the New Brunswick government.
Cancer patients at the affected Ontario and New Brunswick hospitals were told to contact their oncologists after the discovery of the diluted drugs in late March.
Marchese has said its products weren't defective, and suggested that the problem wasn't how the drugs were prepared but how they were administered at the hospitals.