These drugs target specific proteins or genes in cancer cells that tell cancer cells to grow and divide — but not all targeted therapies work the same.

New insights into the cancer genome have led to many new targeted therapies for advanced breast cancer. This promising field of cancer treatment identifies and attacks cancer cells more effectively.

Here’s what to know.

Targeted therapies identify and attack specific proteins or genes in cancer cells without harming healthy cells.

Different types of breast cancer respond to different types of targeted therapy based on which cells fuel the cancer growth. For example, hormone receptor-positive (HR-positive) breast cancer might respond best to a different targeted therapy than cancer related to an overproduction of human epidermal growth factor receptor 2 (HER2).

Your doctor will conduct a biopsy of the cancer to help determine which type of cancer you have. This can help identify the type of targeted treatment the cancer might best respond to.

Who is a candidate for targeted therapy?

It varies based on the tumor biology, receptor status, and you.

When the Food and Drug Administration approves a particular targeted therapy, they define the specific circumstances for when it can be used. They also define who is a good fit for treatment.

In general, targeted therapies are used to treat cancer that has a particular mutation or pathway that the treatment can detect and treat. Targeted therapy may also be an option for people whose cancer did not respond to other therapies, has spread, or is not suitable for surgery.

Types of targeted therapy

Different types of breast cancer respond to different targeted therapies.

Targeted therapies for HR-positive breast cancer include:

  • CDK4/6 inhibitors
  • mTOR inhibitors
  • PI3K inhibitors
  • antibody-drug conjugates

HR-positive breast cancer is also typically treated with hormone therapy, such as selective estrogen receptor modulators (SERMs), selective estrogen receptor degraders (SERDs), or aromatase inhibitors.

Targeted therapies for HER2-positive breast cancer include:

  • monoclonal antibodies
  • antibody-drug conjugates
  • kinase inhibitors

Targeted therapy options used for triple-negative breast cancer include antibody-drug conjugates and PARP inhibitors.

PARP inhibitors are also the only targeted therapy currently used to treat BRCA gene mutations.

Each of these drugs works differently. Some block hormones or proteins linked to cancer spread and growth. Others stop cancer cells from dividing or growing.

In some cases, these drugs can be combined to achieve the best possible outcomes.

A variety of targeted therapies are available for treating breast cancer and fall within the following drug classes:

Antibody-drug conjugates:

  • ado-trastuzumab emtansine (Kadcyla)
  • fam-trastuzumab deruxtecan-nxki (Enhertu)
  • sacituzumab govitecan-hziy (Trodelvy)

Aromatase inhibitors:

  • anastrozole (Arimidex)
  • exemestane (Aromasin)
  • letrozole (Femara)

CDK4/6 inhibitors:

  • abemaciclib (Verzenio)
  • palbociclib (Ibrance)
  • ribociclib (Kisqali)

Kinase inhibitors:

  • lapatinib ditosylate (Tykerb)
  • neratinib maleate (Nerlynx)
  • tucatinib (Tukysa)

Monoclonal antibodies:

  • margetuximab-cmkb (Margenza)
  • pembrolizumab (Keytruda)
  • pertuzumab (Perjeta)
  • pertuzumab, trastuzumab, and hyaluronidase-zzxf (Phesgo)
  • trastuzumab (Herceptin)

mTOR inhibitors:

  • everolimus (Afinitor)

PARP inhibitors:

  • olaparib (Lynparza)
  • talazoparib tosylate (Talzenna)

PI3K inhibitors:

  • alpelisib (Piqray)


  • elacestrant dihydrochloride (Orserdu)
  • fulvestrant (Faslodex)


  • tamoxifen citrate (Soltamox)
  • toremifene (Fareston)

Targeted therapies are generally administered in one of two ways: as a pill or an injection.

Most oral drugs can be taken at home. You may need to visit your doctor or clinic for injections.

Depending on the drug, it may be taken daily, weekly, or monthly. Some treatments are given in cycles, meaning you go through periods of active treatment and periods of treatment breaks. The exact frequency and length of treatment varies based on factors like staging, which drug you’re taking, and how your body reacts to treatment.

How you feel during treatment can also vary and is difficult to predict.

Your doctor will likely schedule frequent follow-up visits to monitor how well the treatment is working and how well you’re tolerating it.

Targeted therapy is considered an effective breast cancer treatment. However, exact success rates vary based on factors such as:

  • cancer type
  • cancer stage
  • tumor receptor status
  • mutation status
  • line of therapy

These breast cancer treatment options work differently.

Standard chemotherapy works on a broad level by killing both healthy cells and rapidly dividing cancerous cells.

But cancer cells are different from healthy cells. Targeted therapies work to detect cancerous cells and then destroy or impede the growth of these cells without harming noncancerous cells.

There are pros and cons to each treatment.

For example, targeted therapies tend to have fewer side effects than standard chemotherapy drugs.

However, cancer cells can become resistant to targeted therapy by mutating so that the drug is no longer effective. When this happens, the cancer can find a new pathway to achieve growth.

In some instances, targeted treatment may work best by combining it with another targeted therapy or more traditional chemotherapy drugs.

Targeted therapy is a new form of breast cancer treatment. Various options are available that can be used on their own or in combination with other drugs to support the best possible results.

With targeted therapy, treatment is very individualized based on underlying factors that may be fueling the cancer’s growth. It’s important to work closely with your doctor to determine your best course of treatment.