Keytruda for Mesothelioma

FDA Approval of Keytruda for Mesothelioma

The U.S. Food and Drug Administration approved Keytruda in June 2020 for a segment of unresectable or metastatic cases of malignant pleural mesothelioma (mesothelioma of the lung cavity lining). Patients must have a high tumor mutational burden, meaning the tumor has a high volume of genetic mutations.

In malignant mesothelioma, the high TMB is due to high levels of PD-L1. Keytruda is also approved for non-small cell lung cancer, but it is not yet approved for peritoneal mesothelioma (mesothelioma of the abdominal cavity lining).

Pembrolizumab is only approved as a second-line treatment for mesothelioma. Patients also must have tried chemotherapy first before receiving Keytruda for mesothelioma. The only way patients can get Keytruda as a first-line treatment is through a mesothelioma clinical trial.

Unresectable means surgery cannot be performed as it will not benefit the patient. This usually describes late-stage mesothelioma (stage 3 or stage 4).

The FDA approval came along with the FoundationOneCDx assay (Foundation Medicine, Inc.) as a companion diagnostic for pembrolizumab. FoundationOneCDx is to be used to help identify patients with types of solid tumors who may be eligible for treatment with pembrolizumab.

How Keytruda Works for Mesothelioma

Keytruda is a type of immunotherapy drug called a checkpoint inhibitor. These types of drugs boost the immune system’s ability to respond to cancer. In more technical terms, pembrolizumab stops cancerous proteins from subduing the immune system. While this treatment has helped patients, it is not a cure for mesothelioma.

PD-1 and PD-L1

The immune system has soldier cells, known as T cells, that attack and kill diseases. However, mesothelioma cells have surface proteins that subdue T cells.

Mesothelioma tumors include a protein called PD-L1, which interacts with the PD-1 protein found on T cells. When PD-L1 and PD-1 bind together, T cells no longer recognize mesothelioma tumors as a threat to the body. This means they cannot actively fight off disease, allowing cancer to spread freely.

Keytruda Blocking PD-L1

Keytruda blocks interactions between PD-L1 and PD-1 proteins, preventing the binding of the two proteins. By blocking the interaction, T cells remain active and alert, ready to fight off mesothelioma.

The therapy helps the immune system to attack, helping it kill cancer cells and preventing them from growing and spreading throughout the body.

Mesothelioma Survival With Keytruda

The FDA looks at two factors when approving or rejecting a therapy for a disease: safety and survival. Keytruda provided patients and specialists with hopeful mesothelioma survival rates.

The approval came shortly after the success of a clinical trial for tumor mutational burden-high (TMB-H) cancers:

• 24% of participants in the clinical trial had a partial response rate (meaning their disease shrunk slightly).
  
• 5% had a complete response (meaning their disease shrunk significantly or completely).
  

The clinical trial also compared how Keytruda helped TMB-H patients and non-TMB-H patients:

• 26.4% of TMB-H cancer patients had progression-free survival for one year, compared to just 14% of the non-TMB-H patients.
  
• 18.9% of TMB-H patients had progression-free survival for two years, compared to just 6.5% of people with non-TMB-H cancers.

Side Effects of Keytruda

Safety is often measured in side effects. Chemotherapy’s side effects range from mild fatigue to severe nausea. Chemotherapy for mesothelioma also weakens bones and causes neuropathies or nerve damage in extremities.

The side effects of Keytruda are not usually as intense. They include:

• Fatigue
  
• Muscle pain
  
• Rash
  
• Diarrhea
  
• Fever
  
• Cough
  
• Decreased appetite
  
• Itching
  
• Shortness of breath
  
• Constipation
  
• Bones, joints or abdominal pain
  
• Nausea
  
• Low levels of thyroid hormone
  

If your side effects become more severe, consult your doctor. You may be eligible for a different immunotherapy treatment, or your doctor may elect to try a different type of mesothelioma treatment.

Process of Keytruda for Mesothelioma

Keytruda is given through an IV (intravenously) in 30-minute increments every few weeks. The therapy is usually given every three weeks.

Mesothelioma patients can receive the immunotherapy medication as long as they want. Some patients continued receiving Keytruda every few weeks for multiple years. The length of your treatment depends on how mesothelioma responds to the immunotherapy and whether you experience severe side effects.

How to Get Keytruda for Mesothelioma

The first step is to receive a medical diagnosis. This requires a consultation from your doctor, imaging tests to look for evidence of cancer and a biopsy at a hospital or cancer center.

If your mesothelioma is in an early stage, you may be a candidate for surgery. This is the best option for treatment. If surgery isn’t possible, then you can ask about Keytruda.

Mesothelioma patients can go to their local medical facility or a top cancer center for regular doses of immunotherapy, as many local cancer hospitals and oncologists offer the treatment. However, it’s recommended for patients to see a mesothelioma doctor first to make sure Keytruda is the right treatment option. Most local oncologists don’t know the best ways to treat mesothelioma.

Mesothelioma Guide has free resources to help you get treated with this immunotherapy, other immunotherapy drugs like Keytruda, or another treatment for mesothelioma. You have the best chances of receiving immunotherapy at a top-ranked mesothelioma cancer center. These facilities are more likely to provide therapies other than chemotherapy. Some examples include:

• Brigham and Women’s Hospital in Boston
• Baylor St. Luke’s Medical Center in Houston
• Moffitt Cancer Center in Tampa
• University of San Francisco Medical Center