Health·second opinion

New buzz about immunotherapy

Why is everyone so excited about CAR-T cancer therapy? And how long does it take to list a hazardous chemical in Canada?

Hopes for a new cancer therapy, and concern about a toxic compound in rubber tires

The human T-cell, pictured here in a scanning electron micrograph, is key to CAR-T immunotherapy. (U.S. National Institute of Allergy and Infectious Diseases)

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Through the simple act of voting Yes, an expert committee of the U.S. Food and Drug Administration created a buzz this week among biotech watchers and cancer scientists.

The influential advisory group gave unanimous approval for a new form of cancer therapy called chimeric antigen receptor T-cell therapy (CAR-T). If the FDA gives final approval in the fall, it will be the first time this form of immunotherapy will be commercially available to patients. So far it's only been tried in formal clinical trial settings.

"I think in the field everybody is very excited that this is moving forward, but it's not without challenges," said John Bell, at the Ottawa Hospital Research Institute. He's the scientific director of a Canadian network of researchers studying novel cancer therapies including CAR-T.

We're not there yet, but the only way to get there is to have trials like these open in Canada.- John Bell, Ottawa Hospital Research Institute

"From a Canadian perspective we still don't really have access to this. We're working to try to get CAR-T therapy going in Canada as soon as possible."

CAR-T therapy is not a drug. It's part of a new generation of highly personalized treatments. It requires intensive engineering of a patient's white blood cells, which are extracted and then genetically modified to carry a specific receptor that will bind to cancer cells. The reprogrammed immune cells are infused back into the body to find and destroy the cancer.

But sometimes the CAR-T cells also attack healthy tissue, and there's the potential for a catastrophic immune response.

"It's very effective, but it's not without issues," said Bell. "Occasionally patients have had such severe reactions to the therapy that they've died."

Those dire side-effects have already halted the trial of one CAR-T therapy in development.

"But the only way you learn, unfortunately, is by treating patients, because you can't predict these things from animal models. And so it's important to keep doing this and finding what the problems are and solving them."

Bell's group has funded two Canadian teams, in B.C. and in Ottawa, to work on developing a Canadian CAR-T program. But he said it won't be ready for patient trials for at least a year.

"We're not there yet, but the only way to get there is to have trials like these open in Canada."

In theory, the CAR-T platform could be modified to treat many different kinds of cancers. So far the best results have been seen in the treatment of acute lymphoblastic leukemia (ALL) and other blood cancers.

How long does it take to put a hazardous chemical on Canada's list of toxic substances?

So far, 11 years and counting. That's how long government scientists have been working to get a chemical used in rubber tires put on the official list of toxic chemicals under the Canadian Environmental Protection Act.

The process began in 2006 when Ottawa identified 200 high-priority compounds and grouped them into batches for regulatory consideration. BENPAT was one of them.

It's a compound made up of three chemicals (1,4-Benzenediamine, N,N'-mixed phenyl and tolyl derivatives), which is imported to Canada and added to rubber tires to make them last longer. The compound gets into the environment in two ways: from industrial release and from the abrasion of tires when the rubber hits the road.

For years, federal government scientists have been working to get a chemical used in rubber tires put on the official list of toxic chemicals. (Shutterstock)

Although no human health risk was established, government scientists determined that BENPAT is a persistent pollutant that is "highly hazardous to aquatic organisms." In 2011 Environment Canada announced its intention to reduce the release of BENPAT in the environment "to the greatest possible extent."

But today BENPAT is still not on the list of toxic substances. Just as Ottawa was about to make it official in 2011, Goodyear Canada filed a notice of objection, demanding a review of the environmental assessment process. When the minister refused, Goodyear Canada filed for a judicial review in Federal Court. The company lost on the first try, and then appealed in 2016. On Monday, it lost again, when the Federal Court of Appeal dismissed Goodyear's appeal.

What happens now? Environment Canada told CBC Health in an email that it is reviewing the Federal Court decision and deciding whether to proceed with putting BENPAT on the toxic substance list.

"We are disappointed in the ruling," Goodyear Canada spokesperson James Peate told CBC Health in an email. "We will review the decision and consider our options. We take seriously our responsibility to care for our associates, communities and the environment, and our facilities will always comply with applicable regulations."

"This is an example of the problems that we have with our legislative framework that governs the way toxic chemicals are regulated," said Muhannad Malas of Environmental Defence. "The issue of timelines has been an issue that for many years we've worked to try to improve."

In June the House of Commons standing committee on environment and sustainable development recommended a series of changes to the Canadian Environmental Protection Act. Environmental groups applauded the proposed changes in part because they would tighten timelines of risk management actions, Malas said.

Ottawa to egg donors: show your receipts

It's taken almost 14 years for Health Canada to fill in the fine print around rules governing assisted reproduction.

The Assisted Human Reproduction Act was passed in 2004, prohibiting the sale of human eggs and sperm. But many provisions of the act have not yet been brought into force.

And that has created confusion over when and whether Canadians can receive money after donating their eggs, sperm or acting as surrogates for infertile couples.

Travel expenses, medicine and maternity clothes are among the expenses that surrogates could claim. (Shutterstock)

This week Health Canada released the list of expenses eligible for reimbursement, including payment for loss of work-related income. Travel expenses, medicine and maternity clothes for surrogates will also be permitted. Receipts and other documents will be required.

There will be no obligation to reimburse, however. And no one is supposed to benefit financially.

"Reimbursement must not involve monetary gain," the regulations say. "Nor should it be disguised as a form of payment or purchase."

The policy proposals are open for public consultation until Sept. 9.

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