Hope is important if you have cancer.
When former President Jimmy Carter announced in December 2015 he was melanoma-free as a result of the prescription drug Keytruda, melanoma patients had a glimmer of hope. Maybe this is the cure, they thought.
And rightly so. Keytruda’s early trials have shown promising results for certain patients with melanoma and lung cancer. In the next few minutes, we’ll walk you through what the drug is, what it treats, how it combats cancer, what the side effects are and, based on the available research, how effective it is.
What is Keytruda and what does it treat?
Keytruda is an injectable cancer drug whose clinical name is pembrolizumab. Pharmaceutical company Merck manufactures the drug, which is classified as a PD-1 blocker (more on that later).
According to Merck’s Keytruda website, the drug is used to treat very specific cases of melanoma (a type of skin cancer) and lung cancer.
The Food and Drug Administration approved Keytruda for advanced melanoma in September 2014 and for non-small cell lung cancer in October 2015. Both were under the FDA’s accelerated approval program.” We emailed with FDA Press Officer Sarah Peddicord about what this means.
Sarah said ‘accelerated approval’ means the FDA thinks a drug can help patients right away even though the long-term benefits of the drug aren’t proven in trials. Merck is responsible for continuing to providing the FDA with data from their trials.
Keytruda’s use for advanced melanoma
As we mentioned, President Carter played a big role in publicizing Keytruda. This was good news for melanoma patients who hadn’t heard of the drug. However, the drug is a double-edged sword – it has been proven to work, but only in certain cases of melanoma. If you decide to try Keytruda, you need to meet each of these requirements:
- The cancer has metastasized (spread) and/or is inoperable.
- You’ve tried the drug ipilimumab and it doesn’t/didn’t work.
- Your tumor has resisted another drug known as a BRAF inhibitor (it blocks mutated BRAF genes that cause the cancer to grow).
One of the questions you might have is, How many melanoma patients can actually use this drug? Well, according to Aetna’s pembrolizumab page, each year about 20% of melanoma cases are discovered after the cancer has spread (one of the requirements for treatment). Considering about 76,000 new cases of melanoma emerge each year, we’re looking at less than 15,000 people who can use this drug.
Keytruda’s use for lung cancer
Just like its use for melanoma, only certain lung cancer patients can use Keytruda as treatment. To start, you have to be diagnosed with non-small cell lung cancer. About 85-90% of lung cancer patients fall into this category. Then, you’ve got to meet the following requirements:
- Your cancer has spread.
- Your chemotherapy treatments included platinum and they didn’t work.
- Your tumor resisted another group of drugs called ALK and EGFR inhibitors (it blocks ALK and EGFR genes that cause the cancer to grow).
How does Keytruda fight cancer?
Keytruda is part of a new group of cancer drugs called PD-1 blockers. Let’s use an example to explain what “PD-1” actually means.
Think of your body’s cancer fighting cells (T cells) as soldiers. Each soldier has a protein on it (PD-1), sort of like a radio link to the captain overseeing the soldiers that tells them whether or not to attack incoming cancer cells.
The cancer cells know this, and they’ve devised a way to fool the T cells. As they approach the T cells, they hack into the radio signal with their own software (a PD-1 activator) and tell the T cells not to attack. So, the cancer cells multiply because nobody is stopping them.
Keytruda is basically a layer of security that keeps cancer cells from hacking into the T cells’ radio system. Next time your T cells run across a melanoma cell or a lung cancer cell, they attack instead of succumbing to the cancer cell’s hack.
What kind of side effects can you expect from Keytruda?
So, remember how we said Keytruda blocks the cancer cell hack and tells your T cells to attack? Some of the side effects of the drug result from your T cells attacking non-cancerous cells along with cancerous cells. Ketyruda’s websites lists the following major side effects:
- Colitis and tears/holes in your intestines
- Gland problems
- Nephritis and kidney failure
- Guillan-Barre syndrome
These side effects are pretty serious, but, according to the FDA, they were uncommon.
Instead, the most common side effects of Keytruda treatments for melanoma patients are: fatigue, nausea, itchy skin, rash, decreased appetite, constipation, joint pain, cough and diarrhea.
Common side effects for lung cancer patients (in addition to the major side effects above) are: fatigue, decreased appetite, shortness of breath, impaired breathing and cough.
How effective is Keytruda for fighting cancer?
Keytruda’s effectiveness can be split into two categories: advanced melanoma and non-small cell lung cancer:
The FDA pointed out that the original trial for Keytruda included 173 patients with advanced melanoma. Half of the group took the recommended dose of 2 milligrams per kilogram for 30 minutes every three weeks. The other half took 10 milligrams per kilogram at the same frequency.
About one in four patients in both groups saw their tumors shrink for as short as 1.4 months and in some cases, the effectiveness lasted more than 8.5 months. The information we found from the FDA did not say how much Keytruda helped shrink tumors after 8.5 months, only that it continued to be “effective.”
Fighting non-small cell lung cancer
Keytruda treatments for non-small cell lung cancer (NSCLC) were compared to the effectiveness of docetaxel, a popular chemotherapy treatment.
The drug was given to patients in the same dose as advanced melanoma patients.
According to a Merck press release, “treatment with Keytruda was associated with longer overall survival compared with docetaxel treatment.” In a group of 61 patients who met all the criteria we mentioned at the beginning of this article, tumor size shrank by 41 percent and lasted between 2.1 and 9.1 months.
Though we’d like to give you specific data about how much more effective Keytruda is over docetaxel, we cannot because the trials are still in process and final results haven’t been posted and won’t be until 2020 (you can keep track of the study here). However, the FDA felt like the initial results were effective enough to allow the drug for use with specific NSCLC patients.
How should I feel about Keytruda? Is it right for me?
After looking through research from Merck and information from the FDA, we think the data is encouraging, especially for NSCLC patients whose cancer has spread and who have, unsuccessfully, used platinum chemotherapy and GRAF inhibitors.
Keytruda’s common side effects are similar to those of other cancer drugs (fatigue, nausea, etc.). The worst side effects of the drug are uncommon, according to the FDA. That’s good news.
The difficult part about Keytruda’s effectiveness is that it’s works for a certain type of advanced melanoma and NSCLC patients. And you have to go through at least two other unsuccessful treatments in order to receive it. That’s a difficult road to walk, and one we certainly don’t wish on any patient.
However, let’s return to the concept of hope. PD-1 blockers are a new and promising area of cancer drugs. Keytruda did some serious damage to NLSCLC tumors. The effects weren’t as great in the advanced melanoma groups, but the results (one out of four people) were still there.
It’s also a good sign that the FDA gave the drug accelerated approval. They believe there are some immediate benefits to the drug. Keep an eye out for future confirmation from Merck about the long-term effectiveness of Keytruda.
We encourage you to talk with your doctor and your family about Keytruda. Do some research on your own. Talk with patients who were treated with it, if you can. But if the preliminary studies are any indication, Keytruda might give some real hope to patients looking for a powerful weapon in their battle against cancer.
Think Keytruda isn’t a good fit for you? If so, FDA Press Officer Sarah Peddicord mentioned that Opdivo is another PD-1 blocker approved for advanced melanoma patients just a couple of months after Keytruda. In their study, the FDA said of the 120 people who took Opdivo, 32 percent of them “had their tumors shrink.” So even if you aren’t a match for Keytruda, there might be similar options that could work equally well!