The province has called on a University of Waterloo doctor to lead a review of its drug supply process after more than 1,100 patients in two provinces received watered-down chemotherapy drugs, including at the London Health Sciences Centre.

The doctor, Jake Theiessen, has previously advised both the Ontario and federal governments.

"His expertise and leadership will help us to find answers - and if there are lessons to be learned from this incident - you have my assurance that action will be taken," says London MPP and Health Minister Deb Matthews.

Her Liberals say the review will focus on the drugs that were administered to cancer patients at four Ontario hospitals and one in New Brunswick.

In London, 665 patients were treated with the diluted product.

The Liberals say they want to determine how the drugs were watered down and get recommendations.

Thiessen will be assisted by a working group that includes people from the affected hospitals, Cancer Care Ontario, Health Canada, the New Brunswick government and the Ontario College of Pharmacists.

Separate investigations by Health Canada and the Ontario College of Pharmacists are already underway.

Thiessen is the founding director of the University of Waterloo's School of Pharmacy.

With files by CTV London