Targeted Therapy for Metastatic Breast Cancer

Targeted therapy uses drugs to target specific changes in cancer cells that help them grow, divide, and spread. Targeted therapy drugs are designed to be more precise. They fight cancer cells while causing less harm to other cells in the body.  

There are different types of targeted therapy. You may get targeted therapy alone or in combination with other treatments, like chemotherapy or hormonal therapy. 

These are the latest types of targeted therapies that are available to treat metastatic breast cancer. New treatments become available all the time, so this may not be a complete list. 

Please note: The side effects listed here do not represent a comprehensive list. It's important to discuss all potential side effects of a drug with your health care team. Be sure to tell your health care team about any side effects you do have.

All Available Treatments

Treatment Type

Anti-HER 2 Monoclonal Antibody

Drug Names
Herceptin® (trastuzumab) and its biosimilars:
Herzuma® (trastuzumab-pkrb)
Kanjinti™ (trastuzumab-anns)
Ontruzant® (trastuzumab-dttb)
Ogivri™ (trastuzumab-dkst)
Trazimera™ (trastuzumab-qyyp)
Margenza™ (margetuximab-cmkb)
Perjeta® (pertuzumab)
Phesgo™ (pertuzumab, trastuzumab, and hyaluronidase-zzxf)
Potential Severe Side Effects
Lung problems Heart problems
Potential Side Effects - All Drugs
Diarrhea Fatigue/weakness Skin/nail changes Hair thinning/loss Adverse drug reaction
Potential Side Effects - Herceptin and its biosimilars
Flu-like symptoms
Important Things to Know
  • This treatment is for HER2+ cancer.
  • This treatment can work well to control MBC with few side effects.
  • Side effects often lessen after the first treatment.
  • Lung problems are a rare but serious side effect.
  • Heart damage is a rare but serious side effect, especially in older people or those who have had prior anthracycline treatment. Your doctor will test your heart function before, during, and after treatment.
  • Herceptin is available as an IV or an injection under the skin.
  • Phesgo is a combination of Perjeta and Herceptin available as an injection.  
  • Margenza is for patients who have received 2 or more anti-HER 2 treatments.
  • Infusion reactions are rare, but are more common with Margenza.

Treatment Type

Tyrosine Kinase Inhibitor

Drug Names
Tykerb® (lapatinib)
Nerlynx® (neratinib)
Tukysa® (tucatinib)
Potential Severe Side Effects - All Drugs
Liver problems
Potential Severe Side Effects - Tykerb
Heart problems
Potential Side Effects
Diarrhea Fatigue/weakness Nausea/vomiting Skin/nail changes
Important Things to Know
  • This treatment is for HER2+ cancer.
  • This treatment is used with Xeloda® (chemotherapy drug) and Herceptin when HER2+ cancer no longer responds to Herceptin alone.
  • Liver problems are a rare but serious side effect.
  • Heart damage is a rare but serious side effect of Tykerb.
  • Take Tykerb 1 hour before eating or 2 hours after eating.
  • Take Nerlynx with food to decrease nausea.
  • Avoid grapefruit while taking.

Treatment Type

Antibody-drug Conjugates

Drug Names
Kadcyla® (ado-trastuzumab emtansine)
Trodelvy® (sacituzumab govitecanhziy)
Enhertu® (fam-trastuzumab deruxtecan-nxki)
Potential Severe Side Effects
Lung problems Heart problems
Potential Side Effects - All Drugs
Abnormal lab tests Bleeding Low blood counts
Potential Side Effects - Trodelvy
Diarrhea
Important Things to Know
  • Kadcyla and Enhertu are used for HER2+ cancer. Kadcyla and Enhertu are a combination of Herceptin and a chemotherapy drug.
  • Trodelvy is used for triple-negative breast cancer.
  • Diarrhea is a common side effect with Trodelvy.
  • There is an increased risk of abnormal liver function tests.
  • Lung problems and heart damage are rare but serious side effects.
  • Low blood counts are a potential side effect that may put you at risk for anemia, infection, or bleeding.

Treatment Type

MTOR Inhibitors

Drug Name
Afinitor® (everolimus)
Potential Side Effects
Abnormal blood tests Diarrhea Fatigue/weakness Lung problems Mouth sores Nausea/vomiting Skin/nail changes
Important Things to Know
  • This treatment is for HR+/HER2- cancer.
  • There is an increased risk of abnormal blood tests, such as elevated levels of glucose and elevated lipids (cholesterol).
  • Light can affect this medicine.
  • Do not take with grapefruit juice or St. John's wort.
  • Antifungal drugs, like fluconazole, may make this medicine stronger or worsen its side effects.
  • Tell all your doctors you are taking this drug.
  • Afinitor must be kept in the packaging it comes in.
  • Mouth sores are a potential side effect that can be painful and affect your oral intake. Speak to your provider about proactive management and an oral care regimen.

Treatment Type

PARP Inhibitors

Drug Names
Lynparza® (olaparib)
Talzenna® (talazoparib)
Potential Severe Side Effects - Talzenna
Liver problems
Potential Side Effects
Diarrhea Fatigue/weakness Hair thinning/loss Weight/appetite changes Low blood counts Nausea/vomiting
Important Things to Know
  • This treatment is for HER2-/BRCA+ cancer.
  • Low blood counts are a potential side effect that may put you at risk for anemia, infection, or bleeding.
  • Bone marrow problems are a rare but serious possible side effect of Lynparza.  
  • Liver problems are a rare but serious possible side effect of Talzenna.
  • This treatment may interact with other drugs. Tell your doctor about everything else you are taking.
  • Avoid grapefruit and grapefruit juice while taking.                    

Treatment Type

CDK 4, 6 Inhibitors

Drug Names
Verzenio® (abemaciclib)
Ibrance® (palbociclib)
Kisqali® (ribociclib)
Potential Side Effects - All Drugs
Diarrhea Fatigue/weakness Low blood counts Nausea/vomiting
Potential Side Effects - Kisqali and Ibrance
Hair thinning/loss
Important Things to Know
  • This treatment is for HR+/HER2- cancer. It's currently being studied for HR+/HER2+ cancer.
  • Low blood counts are a potential side effect that may put you at risk for anemia, infection, or bleeding.
  • Ibrance and Kisqali are given in 4-week cycles with 3 weeks of drug, then 1 week off. Verzenio is continuous.
  • Diarrhea is most common with Verzenio. Ask your doctor about taking an anti-diarrheal medicine before treatment.
  • Avoid grapefruit and grapefruit juice while taking.                     

Treatment Type

PI3K Inhibitor

Drug Name
Piqray® (alpelisib)
Potential Severe Side Effects
Urinary, kidney, or bladder changes Liver problems
Potential Side Effects
Diarrhea Fatigue/weakness Weight/appetite changes Low blood counts Mouth sores Nausea/vomiting Skin/nail changes Blood sugar changes
Important Things to Know
  • This treatment is for HR+/HER2-/PI3K+ breast cancer in men and post-menopausal women.
  • It is given with Faslodex® (hormone therapy drug).
  • This treatment may interact with other drugs. Tell your doctor about everything else you are taking.
  • A change in kidney function or liver function is possible.
  • Do not take with grapefruit, grapefruit juice, or St. John's wort.  
  • Low blood counts are a potential side effect that may put you at risk for anemia, infection, or bleeding.
  • Mouth sores are a potential side effect that can be painful and affect your oral intake. Speak to your provider about proactive management and an oral care regimen.                   

Treatment Type

Kinase Inhibitors

Drug Name
Truquap® (capivasertib) (Pill)
Potential Side Effects
Abnormal lab tests Diarrhea Nausea/vomiting Skin/nail changes
Important Things to Know
  • Truqap® treats advanced or metastatic HR+, HER2-negative breast cancer with one or more PIK3/AKT/PTEN-alterations. 
  • Truqap® must be used in combination with fulvestrant, a horomone treatment.