Your mother keeps her pills beside the coffee tin. She has taken them with breakfast for three years and jokes with the pharmacist about loyalty points. Then a scan says "progression", which means the cancer is growing again.

Her cancer feeds on estrogen, like most breast cancers. The pills held it back for years, and eventually it found a way around them. That almost always happens, so treatment works like a relay race: each drug runs one leg, then hands over.

In 2026, three new drugs for that next leg were approved in the U.S. Which one fits her depends on a single test, and she probably hasn't had it since she was first diagnosed.

If the new test shows this, ask about this drug
No change in a gene called PIK3CA Revtorpyk, given by IV. Held the cancer back about 9 months, compared with 2.
A change in a gene called ESR1 Veppanu, a daily pill. Held the cancer back about 5 months, compared with 2.
An ESR1 change found early, in a blood test Etcamah, swapped in before the cancer grows. Approved early; benefit still being confirmed.

Why the old test isn't enough

Think of estrogen as a key and the cancer cell as a lock. Her pills work by jamming the lock. Over time, the cancer can reshape the lock so the pills no longer fit.

The reshaping is a gene change, and it often appears only after years of treatment. Her first biopsy can't show it. A new test can, often with a simple blood draw that reads bits of tumour DNA.

The result now points to a specific drug. One of them, Etcamah, came with real drama. A panel of FDA advisers voted six to three against it in April, and the FDA approved it anyway in September.

A warning from an older pill

Every one of these drugs was approved because it held the cancer back longer. That is good news, but it isn't the same as living longer. An older pill, capivasertib, showed this year that the difference matters. In its final results, it didn't help women live significantly longer.

So when the side effects of a new drug are hard, your mother can ask one plain question: has it been shown to help people live longer, or only to keep scans stable? Her answer to what that trade is worth is hers to make.

Ask for the new test before the next drug is chosen, and ask for the result on paper. It is the one page that decides what she gets next.

Questions readers ask

Are these drugs available in Canada?

Not yet, as far as we could confirm. No Canadian application for Revtorpyk appeared on Health Canada's lists up to 31 August 2026, and we couldn't confirm filings for the other two. Ask the oncologist about trials or access programs.

Is a blood test as good as a biopsy?

Not always. A blood test can miss a gene change if the tumour sheds little DNA. If it finds a change, doctors trust it. If it finds nothing, they may check a tissue sample to be sure.

How often is Revtorpyk given?

In its main trial, it was given by IV once a week for three weeks out of every four, along with a hormone-blocking injection. That means more clinic visits than her breakfast pills ever needed.

This article is for information and does not replace advice from your cancer care team.

Sources

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