Immune checkpoint inhibitors (ICI) help the immune system fight cancer by blocking checkpoint proteins. These proteins act as “on-and-off switches,” meaning they dictate when to activate or halt an immune response. Sometimes, cancer cells use the same checkpoint proteins to turn off or evade immune attacks. Blocking them through ICI therapy removes that advantage.
Glossary of Terms
Before we continue with our discussion, please take note of these terms to avoid confusion:
- Immune system: This defense network within every human body detects and eliminates harmful invaders, including bacteria, viruses, and abnormal cells like cancer.
- Immune checkpoints: These proteins regulate immune responses by signaling immune cells to slow down or stop attacking.
- Immune checkpoint inhibitors: These medications block immune checkpoints and restore the immune system’s functions.
How Do Checkpoint Inhibitors Work?
Immune checkpoints prevent excessive immune responses. They help avoid damage to healthy cells by telling immune cells when to slow down. However, cancer cells sometimes use the same signals to stop immune cells from detecting and attacking them.
ICI therapy disrupts this process. By blocking checkpoint proteins, they reactivate immune cells, particularly T cells, to attack cancer. This approach strengthens the body’s natural defenses and allows the immune system to see the tumor as a threat again.
Types of Checkpoint Inhibitors and Their Targets
Checkpoint inhibitors fall into three main categories based on the proteins they block:
- PD-1 inhibitors: Block the PD-1 protein, helping T cells stay active against tumors.
- PD-L1 inhibitors: Target PD-L1, the protein cancer cells use to evade immune responses.
- CTLA-4 inhibitors: Block CTLA-4, a checkpoint that prevents T cells from multiplying.
Each of these inhibitors restores immune activity in different ways, and doctors choose them based on the type of cancer being treated.
Which Cancers Can Be Treated With Checkpoint Inhibitors?
The U.S. Food and Drug Administration has approved immune checkpoint inhibitors for several cancers. The FDA is also in the process of researching additional applications to expand ICI use for other types of diseases.
In the United States, cancers currently treated with these drugs include:
- Lung cancer (NSCLC and SCLC)
- Melanoma
- Bladder cancer
- Kidney cancer
- Head and neck cancers
- Hodgkin lymphoma
- Triple-negative breast cancer
- Certain colorectal cancers
Research continues to expand their use, with trials exploring how they work in additional cancer and disease types. Outside the U.S., medical providers, including the doctors here at New Hope Unlimited, New Mexico, are already using checkpoint inhibitors and other immunotherapy drugs to treat a broader range of cancers. Decades-long research and clinical trials ensure our methods’ safety and efficacy. Contact us to meet our doctors and learn more about your precision oncology options.
Effectiveness and Success Rates
Effectiveness varies by cancer type and individual factors. About 43.6% of cancer patients in the U.S. are eligible for immune checkpoint inhibitor therapy, and around 12.5% of patients respond to it. Success rates depend on the presence of biomarkers, tumor characteristics, and whether a patient receives ICI therapy alone or with other treatments.
Side Effects and Risks
Checkpoint inhibitors reactivate the immune system, which can sometimes lead to overactivity. This overstimulation can cause inflammation in healthy tissues. Some patients encounter mild side effects, while others face severe cases of:
- Fatigue
- Skin rashes
- Diarrhea
- Joint pain
- Thyroid dysfunction
Serious complications can involve the lungs, liver, or other organs, but doctors monitor for these effects and adjust treatment as needed. For more information, please read our complete guide to Immunotherapy Side Effects and How to Manage Them.
Combining Checkpoint Inhibitors With Other Treatments
Checkpoint inhibitors work best when the immune system fully recognizes and attacks cancer cells. Some treatments enhance this process by making tumors visible to the immune system or amplifying immune responses.
One approach involves using ICI therapy alongside Tyrosine kinase inhibitors (TKIs), Monoclonal antibodies, or PARP inhibitors, which target specific cancer cell markers. These treatments help direct immune cells to the correct targets, increasing the chances of a stronger response. Some studies also suggest that modifying the tumor environment can boost ICI therapy’s overall effectiveness. When tumors create barriers that shield them from immune attacks, certain therapies help break down those defenses.
Innovative strategies focus on strengthening the immune system itself. Scientists are exploring ways to combine checkpoint inhibitors with treatments that stimulate immune cell activity. By increasing the number or effectiveness of immune cells, these approaches aim to help the body sustain a stronger, longer-lasting attack against cancer.
Timing and sequencing, or adjusting when and how to introduce checkpoint inhibitors, can also lead to better results. Some studies suggest that preparing the immune system before starting checkpoint inhibitor therapy could improve response rates. Personalized treatment plans based on genetic markers or immune system profiles are another area of focus.
As checkpoint inhibitors evolve, new strategies continue to refine their efficacy. The goal is to maximize effectiveness and minimize reliance on harsher conventional treatments.
Who Is a Candidate for Checkpoint Inhibitors?
Checkpoint inhibitors don’t work for everyone. Testing helps determine who will benefit most.
Doctors look for:
- PD-L1 expression: Higher levels may predict better responses.
- Tumor mutation burden: More mutations can make tumors easier for the immune system to recognize.
- Microsatellite instability (MSI-high) status: Some colorectal and other cancers with this feature respond well.
A person’s overall health and previous treatments also influence eligibility.
Future Research and Advancements
Research continues to improve checkpoint inhibitors. Scientists are:
- Developing new checkpoint targets beyond PD-1, PD-L1, and CTLA-4
- Studying personalized immunotherapy based on genetic markers
- Testing better combination treatments to increase success rates
New trials are underway to enhance these approaches, making the future of ICI therapy more helpful for a wider range of cancer patients.
The Bottom Line: ICI Therapy Is Turning the Tide Against Cancer
Checkpoint inhibitors have changed cancer treatment by restoring a person’s immune response against malignant cells. While they don’t work for everyone, they’ve helped many live longer with fewer side effects than traditional treatments. As research advances, these therapies will become even more effective and available for more cancers.
Know Your Checkpoint Inhibitor Options With New Hope Unlimited
It wasn’t too long ago when researchers and oncologists in the U.S. were completely against ICI and alternative treatment options. During that time, when skepticism and caution dominated the conversation, we had already done our research and saw promising results.
New Hope Unlimited is one of the pioneering treatment centers for advanced precision oncology. If you want to explore checkpoint inhibitors as part of a broader treatment plan, but your country does not offer it or has no available treatment for your cancer type, write to us or dial 480-666-1403. Let’s discuss your options.
