Targeted therapies are medications that block certain molecules that affect cancer’s ability to grow and spread. They are different from standard chemotherapy and have several potential benefits as a lung cancer treatment.

According to Dr. Timothy Byun, a hematologist and oncologist with the Center for Cancer Prevention and Treatment at St. Joseph Hospital in Orange County, CA, some Food and Drug Administration (FDA)-approved medications target specific genetic mutations that are responsible for lung cancer.

These drugs are often the therapy of choice for people with advanced stage non-small cell lung cancer (NSCLC), said Dr. Byun. NSCLC accounts for an estimated 84% of all lung cancer diagnoses, according to the American Cancer Society.

“In general, targeted therapies have higher response rates and [a] longer duration of benefit compared [with] chemotherapy in these patient subsets,” said Dr. Byun.

However, targeted therapies also have some potential drawbacks. Dr. Byun explained that, as with chemotherapy, a person’s cancer may develop a resistance to these medications. A person may also develop some side effects from taking these medications.

There are several different targeted therapies for people with lung cancer. Individuals should talk with their doctor about which option is best for them.

Here are the most common mutations involved in lung cancer, the targeted therapies that treat them, and some potential side effects related to taking these medications.

Cancerous tumors need a steady blood supply to grow. Angiogenesis inhibitors are a type of long-term medication that targets the blood vessels supporting cancer cells. By blocking the growth of these blood vessels, this targeted treatment can slow or stop the growth of lung cancer.

A doctor is most likely to prescribe bevacizumab (Avastin) or ramucirumab (Cyramza) to treat lung cancer.

Side effects vary based on which part of the blood cells the medication targets. Some common side effects can include:

  • fatigue
  • high blood pressure
  • diarrhea
  • pain, swelling, tingling, numbness, or flushing in the hands or feet
  • hair changes
  • protein in the urine
  • an increased risk of infections (due to low white blood cell counts)
  • biochemical hypothyroidism

Serious side effects are more rare. These may include:

  • holes (perforations) and fistulas in the gastrointestinal tract
  • severe bleeding (hemorrhage)
  • slow would healing
  • heart failure
  • stroke or heart attack (due to a blockage in the arteries)
  • reversible posterior leukoencephalopathy syndrome (a brain condition)

Epidermal growth factor receptor (EGFR) is a protein on the outside of cells that controls their growth and division. EGFR genetic mutations can cause too much EGFR to be present on cells, which causes cancer to grow faster.

EGFR mutations affect around 3745% of people with lung cancer who don’t smoke and 7–14% of people with lung cancer who do smoke.

“For advanced stage NSCLC with common EGFR mutations, EGFR targeted therapy such as osimertinib is the preferred first line of treatment,” said Dr. Byun.

EGFR inhibitors block the signals from EGFR to prevent the growth and division of cancer cells.

Some common EGFR inhibitors for lung cancer include:

  • afatinib (Gilotrif)
  • osimertinib (Tagrisso)
  • erlotinib (Tarceva)
  • dacomitinib (Vizimpro)
  • gefitinib (Iressa)

Some common side effects of EGFR inhibitors can include:

  • appetite suppression
  • diarrhea
  • skin problems, which can lead to skin infections
  • mouth sores

These side effects can be severe enough that doctors recommend that people stop taking EGFR inhibitors.

“For example,” said Dr. Byun, “if a patient experiences a severe adverse reaction such as interstitial lung disease related to osimertinib, which occurs infrequently, then the medication is discontinued and the patient would be considered for chemotherapy.”

EGFR inhibitors that target cells with the T790M mutation

According to one 2018 study, most people with lung cancer develop resistance to EGFR inhibitors. This is often because the cancer cells develop new EGFR mutations. One common mutation is called T790M.

Osimertinib (Tagrisso) is a drug that targets cells with the T790M mutation. Side effects of this drug are similar to those of other EGFR inhibitors.

EGFR inhibitors used for squamous cell NSCLC

Necitumumab (Portrazza) is an EGFR inhibitor that mimics immune system proteins.

A doctor will give the medication intravenously and will often prescribe it with chemotherapy for people with advanced squamous cell NSCLC. It can cause similar side effects to those of other EGFR inhibitors.

Anaplastic lymphoma kinase (ALK) is a protein that supports cell growth. Some people with lung cancer have a mutation in the ALK gene, which causes more ALK proteins to form. This drives cancer growth and spread.

ALK mutations occur in about 12% of people who don’t smoke and 2% of people who currently or who used to smoke.

ALK inhibitors are medications that target cancers with the ALK mutation. Certain people can use them after or instead of chemotherapy.

Some examples of these drugs include:

  • alectinib (Alecensa)
  • brigatinib (Alunbrig)
  • crizotinib (Xalkori)
  • ceritinib (Zykadia)
  • lorlatinib (Lorbrena)

It is possible to experience side effects from taking this drug, including:

  • vision changes
  • fatigue
  • constipation
  • nausea and vomiting
  • diarrhea

Some more severe and rare side effects include:

  • heart rhythm problems
  • liver or nerve damage
  • swelling in the lungs or throughout the body

The American Cancer Society estimate that 1–2% of NSCLC cases have a ROS1 mutation, which affects how cancer cells grow and spread.

According to one recent study, ROS1 inhibitors are a well-established targeted therapy for people with a type of NSCLC lung cancer known as adenocarcinoma. Adenocarcinoma accounts for 50–60% of lung cancer in people who don’t smoke.

If a doctor identifies a ROS1 mutation, they may prescribe one of the following medications:

  • lorlatinib (Lorbrena)
  • crizotinib (Xalkori)
  • ceritinib (Zykadia)
  • entrectinib (Rozlytrek)

People can use these medications instead of chemotherapy or when chemotherapy or other therapies stop working.

Some potential side effects may include:

  • constipation
  • dizziness
  • diarrhea
  • vision problems
  • fatigue

More severe side effects may include:

  • liver or nerve damage
  • swelling in the lungs or elsewhere in the body
  • heart problems

About 1–2% of people with NSCLC develop RET gene mutations. These changes affect a protein involved in cell growth, and they often occur with other mutations. As a result, a doctor may prescribe RET-targeting medications with EGFR-targeting medications for the best effect against cancer.

Medications to target RET genes include selpercatinib (Retevmo) and pralsetinib (Gavreto).

Some common side effects can include:

  • rash
  • high blood pressure
  • dry mouth
  • diarrhea or constipation
  • joint pain
  • hand and feet swelling
  • elevated blood sugar levels
  • muscle pain
  • feeling tired
  • changes in some blood test results
  • low blood counts

More severe and rare side effects may include:

  • problems with wound healing
  • bleeding
  • lung or liver damage
  • heart rhythm changes
  • allergic reactions

According to one 2015 study, changes in the mesenchymal-epithelial transition (MET) gene are present in about 5% of lung cancer cases. The MET gene creates the MET protein, which is involved in cell invasion, growth, migration, and metastasis.

Capmatinib (Tabrecta) is the first FDA-approved MET-targeting medication for treating metastatic NSCLC.

Researchers are currently studying many other types of MET-inhibitor, including emibetuzumab, tivantinib, cabozantiniband, and onartuzumab.

Some potential side effects of these drugs may include:

  • lack of appetite
  • swelling in the hands or feet
  • constipation
  • nausea
  • vomiting
  • weakness or tiredness
  • diarrhea
  • changes in some blood test results
  • sun sensitivity

Rarely, these drugs can cause liver damage and swelling or scarring in the lungs.

Recent research suggests that very few people with NSCLC develop an NTRK gene change that can cause the cancer to grow and spread.

Doctors typically prescribe two medications for this mutation in people with advanced lung cancer: larotrectinib (Vitrakvi) and entrectinib (Rozlytrek). Both are typically given when the cancer does not respond to other treatments.

Some potential side effects include:

  • diarrhea
  • dizziness
  • fatigue
  • constipation
  • vomiting
  • weight gain
  • nausea

Some other, less common side effects include:

  • confusion
  • heart problems
  • irregular liver test results

A number of different drugs provide targeted treatment for many people with lung cancer.

These medications work by honing in on certain mutations in genes involved in lung cancer and stopping the reproduction, growth, and spread of cancer cells.

People may use targeted therapies with, instead of, or following other cancer therapies, including chemotherapy.