How does the drug abemaciclib treat breast cancer?
Abemaciclib, added to Australia’s PBS, drastically cuts breast cancer treatment costs while targeting CDK4/6 in HR+/HER2- cancers.
The anti-cancer drug abemaciclib (also known as Vernezio) has this month been added to the Australian Pharmaceutical Benefits Scheme (PBS) to treat certain types of breast cancer.
This significantly reduces the cost of the drug. A patient can now expect to pay A$31.60 for a 28-day supply ($7.70 with a health care concession card). The price of abemaciclib without government subsidy is $4,250.
So what is abemaciclib, and how did we get to this point?
It stops cells dividing
Researchers at the pharmaceutical company Eli Lilly developed abemaciclib and published the first study on the drug (then known as LY2835219) in 2014.
Abemaciclib is a type of drug known as a “cyclin-dependent kinase inhibitor”. It’s taken as a pill twice a day.
To maintain our health, many of the cells in our bodies need to grow and divide to produce new cells. Cancers develop when cells grow and divide out of control. Therefore, stopping cells from dividing into new cells is one way that cancer can be fought.
When cells divide, they have to make a copy of their DNA to pass onto the new cell. “Cyclin-dependent kinases” (CDKs for short) are essential for this process. So, if you stop the CDKs, you stop the DNA copying, you stop cells dividing, and you fight the cancer.
However, there are different types of CDKs, and not all cancers need them all to grow. Abemaciclib specifically targets CDK4 and CDK6. Thankfully, a lot of cancers do need these CDKs, including some breast cancers.
But abemaciclib will only be effective against cancers that rely on CDK4 and CDK6 for continued growth. This specificity also means abemaciclib is fairly unique, so it can’t easily be replaced with a different drug.
Two other CDK4/6 inhibitors were developed around the same time as abemaciclib, and are called ribociclib and palbociclib. Both of these drugs are also on the PBS for specific types of breast cancer. As the drugs differ in their chemical structures, they have slight differences in the way they are taken up and processed by the body. The preferred drug given to a breast cancer patient will depend on their unique circumstances.
What are the side effects?
Research is still ongoing into the differences between each of these CDK4/6 inhibitors, but it is known that the side effects are largely similar, but can differ in severity.
The most common side effects of abemaciclib are fatigue, diarrhoea and neutropenia (reduced white blood cells). The gastrointestinal issues are generally more severe with abemaciclib.
If these side effects are too severe, abemaciclib treatment can be stopped.
What types of cancer has abemaciclib been approved for?
In 2017, the United States Food and Drug Administration (FDA) approved abemaciclib for the treatment of patients with metastatic HR+/HER2- (hormone receptor-positive and human epidermal growth factor receptor 2-negative) breast cancer who did not respond to standard endocrine therapy.
Australia’s Therapeutic Goods Administration (TGA) similarly approved abemaciclib in 2022 as an “adjuvant” therapy (after the initial surgery to remove the tumour) for patients with HR+/HER2- invasive early breast cancer which had spread to lymph nodes and was at high risk of returning.
As of May 1 2024, the PBS covers this use of abemaciclib in combination with endocrine therapy such as fulvestrant, which is also listed on the PBS. Endocrine therapy, also known as hormonal therapy, blocks hormone receptor positive (HR+) cancers from receiving the hormones they need to survive.
Could abemaciclib be used for other cancers in the future?
Abemaciclib is of great interest to scientists and medical practitioners, and testing is ongoing to assess the effectiveness of abemaciclib in treating a range of other cancers, including gastrointestinal cancers and blood cancers.
Abemaciclib may even be usable in brain cancers, as it has long been known to be capable of crossing the blood-brain barrier, a common stumbling block for potential anti-cancer drugs.
Time will tell whether the role of abemaciclib in health care will be expanded. But for now, its inclusion on the PBS is sure to bring some relief to breast cancer patients nationwide.
Sarah Diepstraten, Senior Research Officer, Blood Cells and Blood Cancer Division, Walter and Eliza Hall Institute and John (Eddie) La Marca, Senior Resarch Officer, Walter and Eliza Hall Institute
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Stop Cancer 20 Years Ago
Dr. Jenn Simmons shares vital tips on preventing cancer and inflammation, advocating for lifestyle changes and proactive health management at any age.
Get Abreast And Keep Abreast
This is Dr. Jenn Simmons. Her specialization is integrative oncology, as she—then a breast cancer surgeon—got breast cancer, decided the system wasn’t nearly as good from the patients’ side of things as from the doctors’ side, and took to educate herself, and now others, on how things can be better.
What does she want us to know?
Start now
If you have breast cancer, the best time to start adjusting your lifestyle might be 20 years ago, but the second-best time is now. We realize our readers with breast cancer (or a history thereof) probably have indeed started already—all strength to you.
What this means for those of us without breast cancer (or a history therof) is: start now
Even if you don’t have a genetic risk factor, even if there’s no history of it in your family, there’s just no reason not to start now.
Start what, you ask? Taking away its roots. And how?
Inflammation as the root of cancer
To oversimplify: cancer occurs because an accidentally immortal cell replicates and replicates and replicates and takes any nearby resources to keep on going. While science doesn’t know all the details of how this happens, it is a factor of genetic mutation (itself a normal process, without which evolution would be impossible), something which in turn is accelerated by damage to the DNA. The damage to the DNA? That occurs (often as not) as a result of cellular oxidation. Cellular oxidation is far from the only genotoxic thing out there, and a lot of non-food “this thing causes cancer” warnings are usually about other kinds of genotoxicity. But cellular oxidation is a big one, and it’s one that we can fight vigorously with our lifestyle.
Because cellular oxidation and inflammation go hand-in-hand, reducing one tends to reduce the other. That’s why so often you’ll see in our Research Review Monday features, a line that goes something like:
“and now for those things that usually come together: antioxidant, anti-inflammatory, anticancer, and anti-aging”
So, fight inflammation now, and have a reduced risk of a lot of other woes later.
See: How to Prevent (or Reduce) Inflammation
Don’t settle for “normal”
People are told, correctly but not always helpfully, such things as:
- It’s normal to have less energy at your age
- It’s normal to have a weaker immune system at your age
- It’s normal to be at a higher risk of diabetes, heart disease, etc
…and many more. And these things are true! But that doesn’t mean we have to settle for them.
We can be all the way over on the healthy end of the distribution curve. We can do that!
(so can everyone else, given sufficient opportunity and resources, because health is not a zero-sum game)
If we’re going to get a cancer diagnosis, then our 60s are the decade where we’re most likely to get it. Earlier than that and the risk is extant but lower; later than that and technically the risk increases, but we probably got it already in our 60s.
So, if we be younger than 60, then now’s a good time to prepare to hit the ground running when we get there. And if we missed that chance, then again, the second-best time is now:
See: Focusing On Health In Our Sixties
Fast to live
Of course, anything can happen to anyone at any age (alas), but this is about the benefits of living a fasting lifestyle—that is to say, not just fasting for a 4-week health kick or something, but making it one’s “new normal” and just continuing it for life.
This doesn’t mean “never eat”, of course, but it does mean “practice intermittent fasting, if you can”—something that Dr. Simmons strongly advocates.
See: Intermittent Fasting: We Sort The Science From The Hype
While this calls back to the previous “fight inflammation”, it deserves its own mention here as a very specific way of fighting it.
It’s never too late
All of the advices that go before a cancer diagnosis, continue to stand afterwards too. There is no point of “well, I already have cancer, so what’s the harm in…?”
The harm in it after a diagnosis will be the same as the harm before. When it comes to lifestyle, preventing a cancer and preventing it from spreading are very much the same thing, which is also the same as shrinking it. Basically, if it’s anticancer, it’s anticancer, no matter whether it’s before, during, or after.
Dr. Simmons has seen too many patients get a diagnosis, and place their lives squarely in the hands of doctors, when doctors can only do so much.
Instead, Dr. Simmons recommends taking charge of your health as best you are able, today and onwards, no matter what. And that means two things:
- Knowing stuff
- Doing stuff
So it becomes our responsibility (and our lifeline) to educate ourselves, and take action accordingly.
Want to know more?
We recently reviewed her book, and heartily recommend it:
The Smart Woman’s Guide to Breast Cancer – by Dr. Jenn Simmons
Enjoy!