Humira, Enbrel, and cancer risk

There’s a scary warning when you read about biologics like Humira and Enbrel: these drugs may increase risk of cancer. Scarier, Humira has a warning that it may cause a rare, deadly type of cancer in young people. After spending many bored hours in doctor’s offices, I’d read the warnings many times on pamphlets and posters. Probably too many, because it made me question whether it was the right choice to start a biologic therapy when my doctor offered it as an option.

Simply put, biologic medications are drugs that are made from living sources, instead of mixing chemicals. They include medicines like Humira and Enbrel for autoimmune diseases and even insulin used for diabetes treatment. Common biologic drugs are injected and need to be refrigerated. Humira and Enbrel in particular contain antibodies that lessen some of the immune response, stopping the body from attacking itself. They can slow down or even stop progression of autoimmune diseases, but they comes with warnings about risk for serious infections or increases in cancer.

(I’m focusing on Humira and Enbrel here because, at least in my experience, these are the most common “starter” biologics.)

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There’s a lot of animosity towards these drugs. They’re scary for a lot of reasons: they’re taken by injection, they’re crazy expensive, and they have dangerous side effects. A quick search for Humira side effects brings up an article bashing the strategies used by Humira’s maker, claiming that Humira is overused when other less expensive, less dangerous medications can be used. That overlooks a lot of factors, though.

Even if a doctor tried to immediately start a patient on a biologic, the patient’s insurance would likely refuse to cover it unless cheaper treatments were tried first (this is called step therapy). For patients who can no longer function because of their disease, biologics, although potentially dangerous, are life savers. They prevent permanent damage to the body and allow people to live their lives again when no other drugs have. It’s a very personal choice to start a biologic, one that can’t be summed up by “biologics are bad.” I’m not saying that better (and less expensive) solutions aren’t needed, but it’s unfair to demonize drugs that have so much potential to help people.

It was a difficult decision for me to decide to start taking Humira, and I was lucky to have access to medical literature that could help me make my decision. I’m going to share what I found out about common biologics and cancer risk, because that’s what worried me most about starting Humira. The warnings on the box don’t tell the whole story.

What I learned

My doctor suggested starting me on Humira after I’d been through countless NSAIDs and DMARDs. When I was hesitant, he told me to think about it and contact the office if I decided it was what I wanted. I didn’t think about it much for a few weeks, until my pain got so bad that I wasn’t getting sleep at night. I knew something had to change, but were biologics the right change?

The cancer warning scared me, especially the fact that the warning for Humira was targeted at young people. But my doctor wouldn’t be suggesting biologics unless he thought they were worth it, right? I decided to dig into the research myself to see what I could find out.

Important: I’m going to focus here on biologics for arthritis, mostly rheumatoid arthritis (RA) due to study availability. Cancer risk has been found to be different for patients taking biologics for different conditions, such as psoriasis and inflammatory bowel disease (IBD). Another important thing to remember is that in medical literature, not all studies will agree, so I go through the different viewpoints here.

An important thing to keep in mind is that having inflammatory arthritis gives you an increased risk for certain types of cancer. Just having it. Studies have found this to be true for for both rheumatoid arthritis and ankylosing spondylitis patients.

I’ve read, and I’ve also heard anecdotally from doctors, that the main reason for the “rare cancer in young people” warning on Humira is because of a very specific reason: some patients, mostly teenage boys and young men, taking Humira in combination with IBD drugs Imuran or Purinethol developed a rare and deadly type of lymphoma.

If you’re just taking Humira or Enbrel for RA, not in combination therapy for IBD, studies have shown that taking a biologic doesn’t change and may actually even lessen cancer risk. Study after study after study report no increased risk when looking at different types of cancer in RA patients taking Humira or Enbrel versus other treatments.

A more detailed breakdown of cancer risk found in some studies shows more of the story. These studies concluded that there was increased risk for certain types of cancers but no increased risk overall (meaning for all types of cancer) compared to people taking other RA treatments.

That means that although people taking biologics had more risk of certain cancers (like lymphoma and non-melanoma skin cancer), they had less risk of other cancers. This balanced out statistically, so that their total risk of developing any type of cancer was the same as people on other treatments. Importantly, a study that included all kinds of conditions treated with biologics found that the same held true for RA, AS, and psoriatic arthritis patients taking Humira when compared to the general population.

Studies have tried to generalize cancer risk for all biologics across all conditions with only limited success because of the sheer volume of data and difficulties with analyzing it in the same way when it comes from different sources. The study referenced above generally found no increased cancer risk (except non-melanoma skin cancer) but had trouble offering more drug-specific results.

My takeaway

While it’s still an important factor to think about, cancer risk wasn’t an immediate reason for me to delay biologics, like I was worried at first. Studies overall have found that cancer risk is the same or less for patients with rheumatoid arthritis who take biologics compared to other treatments, repeatedly over many studies. Studies show that certain types of cancer are more common in patients taking Humira and Enbrel, but certain types are also less common. Knowing that really helped with my concerns about starting Humira.

I’m not writing this to say that better treatments than current biologics aren’t needed, or that biologics and the companies that make them are perfect. I have some pretty strong opinions (that I won’t go into) about the practices used by these companies. I wish I didn’t have to be on Humira myself, but it’s helped me get my life back.

This information is just about cancer, obviously, not about the other warnings associated with biologics (I can go into others if there’s interest). Those others are still important to consider when deciding whether to start a biologic, so talk to your doctor and do some looking on your own. This article is a really useful summary of all serious Humira risks for most conditions that it’s used for.

I’ve tried to give a general overview of the main research on cancer risk associated with Humira and Enbrel. I hope this information has helped!

-Bri

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