Keytruda (Pembrolizumab) for Mesothelioma and Lung Cancer

Keytruda is a brand name for the drug pembrolizumab. This cancer drug was developed, manufactured, and sold by Merck. In 2014, Keytruda was approved by the U.S. Food and Drug Administration (FDA) to treat metastatic melanoma and other cancers, including non-small cell lung cancer in patients with certain biomarkers. This is the first time the FDA has approved a cancer drug based on genetics.

For people affected by asbestos, Keytruda is exciting because early studies suggest it may be a useful chemotherapy drug for mesothelioma. While more research is necessary, results are promising. This could lead to a new therapy for mesothelioma patients with few other options for effective treatment.

Pembrolizumab and Immunotherapy

Keytruda is an immunotherapy drug designed to help the immune system attack and kill cancer cells. The immune system works when cells, recognize and attack foreign invaders in the body. Immune system cells recognize pathogens because of receptors called antigens on their surfaces. Healthy cells in the body have receptors on their surfaces that signal immune cells to leave them alone.

Some cancer cells express these receptors, called PD-1 proteins. This causes immune system cells to mistake cancer cells for healthy cells and leave them alone to grow and thrive. Pembrolizumab acts on these cancer cell receptors, allowing the immune system to recognize them as foreign and attack and them. The strategy is referred to as immune checkpoint blockade.

Indications and Side Effects

The FDA approved Keytruda for specific types of cancers, for cancers in certain stages or with certain characteristics, and for cancer patients with certain biomarkers. For example, it is approved for melanoma, but only melanoma that has spread and cannot be treated surgically. For other cancers, like non-small cell lung cancer, Keytruda is approved only in cases where the patient’s cancer worsened after treatment with standard chemotherapy drugs.

Side effects with pembrolizumab can be serious. The most common side effects are fatigue, rash, diarrhea or constipation, nausea, decreased appetite, shortness of breath, coughing, and itching. More serious side effects are less common but may include bruising, anemia, numbness, dizziness, hot flushes, flu-like symptoms, hair loss, edema, irregular heartbeat, pain, kidney failure, infections, insomnia, diabetes and jaundice. Chest pains, shortness of breath, and a cough may indicate a serious reaction that should be addressed immediately.

Keytruda for Mesothelioma

Right now, indications for Keytruda do not include mesothelioma. However, research is underway to determine if it could be an effective and safe treatment for this cancer. Most recently, a study published in The Lancet Oncology showed promising results. This study shows that while other chemotherapy drugs are failing mesothelioma patients, immune checkpoint drugs may be a better alternative.

The clinical trial is called KEYNOTE-028 and involves 13 research teams in six different countries. The trial includes patients with various types of advanced cancer, including 25 patients with pleural mesothelioma. All patients received unsuccessful chemotherapy treatment prior to the trial or were not eligible for chemotherapy.

The study’s mesothelioma patients received an injection of pembrolizumab every two weeks. As a result, 14 of the patients saw reductions in tumor size. These patients experienced an average of six months of reduced cancer progression. The average survival time was 18 months. Four patients are still alive and undergoing treatment with pembrolizumab, two years later.

While 18 months survival may not sound encouraging, it is a major improvement. Most patients with pleural mesothelioma that receive second-line treatment only survive an additional six months. With four patients surviving past the two-year mark, treatment with Keytruda shows great promise over other options. While there were common side effects, including fatigue and nausea, no patients had to stop taking the drug.

Keytruda for Asbestos Lung Cancer

Pembrolizumab is promising for mesothelioma patients. However, the drug is already approved for non-small cell lung cancer, another cancer that can be triggered by asbestos exposure. Approval for treating this kind of cancer came after clinical trial results showed it to be safe and effective. More recent studies suggest it may be more effective than standard chemotherapy drugs like cisplatin and carboplatin.

This study examined the results of the KEYNOTE-024 clinical trial of pembrolizumab in non-small cell lung cancer patients. Data showed pembrolizumab has several advantages over traditional chemotherapy. Patients given this drug experienced better overall survival rates, fewer side effects that were less severe, and improved quality of life. Some side effects were worse with pembrolizumab. However, overall adverse effects were lower and less severe. The benefits of pembrolizumab were seen in its use as a first-line treatment. This could mean patients with lung cancer may be able to use the drug in place of cisplatin or carboplatin, avoiding adverse effects and achieving better results.

The promise of immunotherapy drugs for cancer treatment is overwhelmingly positive. Keytruda is paving the way to a new strategy for better treatment of mesothelioma. There are now more than 90 ongoing clinical trials using Keytruda to treat various types of cancers.

Approval for Keytruda Expands, Hope for Mesothelioma Patients

In June of 2019 the FDA announced a new indication for Keytruda. It is now approved for the first-line treatment of metastatic, unresectable, or recurring head and neck squamous cell carcinoma (HNSCC). The FDA has approved the immunotherapy drug as part of a combination treatment with chemotherapy but as a stand-alone treatment for HNSCC patients with the right genetic makeup.

This is important news, not just for the HNSCC patients who may now benefit from Keytruda, but also for mesothelioma patients.  HNSCC is a rare cancer that is difficult to treat, just like mesothelioma. The approval for pembrolizumab is an important step in giving these patients more hope of improved survival. It is also a step in the direction of getting drugs like this approved for other rare cancers. It may not be long before it is approved for mesothelioma. The approval came after the clinical trial KEYNOTE-048 showed the drug could significantly prolong patient survival.

Two new mesothelioma trials are expected to start soon. If you are struggling with mesothelioma, pembrolizumab is not currently approved for treatment. However, you may be able to participate in a clinical trial. Talk to your doctor about how to get involved if you qualify for this revolutionary treatment for this difficult type of cancer.

Page Edited by Patient Advocate Dave Foster

Dave has been a mesothelioma Patient Advocate for over 10 years. He consistently attends all major national and international mesothelioma meetings. In doing so, he is able to stay on top of the latest treatments, clinical trials, and research results. He also personally meets with mesothelioma patients and their families and connects them with the best medical specialists and legal representatives available.

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