It’s being called “a critical milestone.”

Toronto’s Princess Margaret Cancer Centre has news today about a new drug they hope will be a breakthrough in treating several types of cancer.

We told you about the drug a month ago and now it has now been approved for clinical trial by Health Canada.

The drug (CFI-40095) was developed by the team led by Doctors  Tak Mak of The Campbell Family Cancer Research Institute and Dennis Slamon of the University of California, Los Angeles.

They are two of the world’s most acclaimed cancer researchers.

In the lab, the drug has been shown to inhibit the growth of human breast and ovarian cancers and other cancers including  colorectal, lung, melanoma, pancreatic and prostate cancers.

Key supporters vital  to the research and  development of the drug have been the thousands of walkers  and their donors in the Shoppers Drug Mart “Weekend To End Women’s Cancers” and other powerful corporate sponsors.

The clinical trial is expected to begin later this year .