AC-THP: Adriamycin and cyclophosphamide, followed by paclitaxel, trastuzumab, and pertuzumab

AC-THP is a chemotherapy combination treatment used to treat early-stage HER2-positive breast cancer. It may also be called sequential AC/Taxol-trastuzumab-pertuzumab.

The medicines in this combination are:

• Doxorubicin (Adriamycin), an anthracycline, and cyclophosphamide (Cytoxan), an alkylating agent, followed by treatment with:
  • Paclitaxel (Taxol), a taxane chemotherapy
  • Trastuzumab (Herceptin) and pertuzumab (Perjeta), two anti-HER2 targeted therapies known as monoclonal antibodies; both medicines work to destroy HER2-positive cancer cells

How AC-THP works

Both doxorubicin and cyclophosphamide (AC) damage the DNA inside cancer cells so they can’t divide, which causes them to die. With doxorubicin, the damage stops the cancer cells from dividing and causes them to die. Cyclophosphamide stops cancer cells from reproducing.

Paclitaxel (T) is added to doxorubicin and cyclophosphamide (AC). It stops cancer cells from dividing into new cells and multiplying.

Trastuzumab (H) and pertuzumab (P) attach to HER2 proteins on the surface of HER2-positive cancer cells and block the signals that cause the cancer cells to multiply.

Who gets AC-THP

AC-THP is often used as adjuvant therapy, after surgery, or as neoadjuvant therapy, before surgery, for early-stage breast cancers that are:

• HER2-positive and have traveled to the lymph nodes
• HER2-positive and have not traveled to the lymph nodes (high-risk lymph node negative)

You and your doctor will discuss the best chemotherapy treatment for your situation.

How AC-THP is given

This regimen is delivered by vein through an intravenous (IV) line. It can also be given through a small, implantable device called a port. Doctors can implant a port under the skin, usually in the chest area. Ports help avoid repeated needle sticks for treatment.

AC-THP can be given before (neoadjuvant) or after (adjuvant) surgery.

• This regimen starts with four cycles of doxorubicin and cyclophosphamide given every 21 days. At each of these chemotherapy treatment sessions, doxorubicin is given first, followed by cyclophosphamide.
• Then, over four 21-day cycles:
  • Trastuzumab and pertuzumab are given on day 1. They are given one after the other.
  • On days 1, 8, and 15, paclitaxel is given.
  • On day 1 when all three treatments are given, trastuzumab and pertuzumab are given first, followed by paclitaxel.
• After finishing paclitaxel, treatment continues every 21 days with trastuzumab and pertuzumab, for a total of 1 year of these two treatments.

Pertuzumab, one of the medicines in this regimen, commonly causes diarrhea. For people who have difficulty with this side effect, pertuzumab is sometimes removed from the regimen.

Side effects & things to remember

Different medicines have different side effects. You may not have every side effect related to each medicine of the combination therapy. Side effects of AC-THP may include:

• Low red and white blood cell counts
• Increased risk of bleeding
• Menopausal symptoms
• Nausea and vomiting
• Hair loss
• Risk of infection
• Mouth sores
• Fatigue
• Joint pain
• Nail and skin changes
• Neuropathy, numbness and tingling in the hands and feet
• Heart damage
• Higher risk of leukemia

Before starting AC-THP, tell your doctor about any medicines you are taking, including vitamins, herbal supplements, and over-the-counter medicines, to make sure they won’t interfere with your chemotherapy treatment.

Trastuzumab can cause complications in pregnancy, so you should not become pregnant while taking it.

Talk with your care team about all your side effects so that they can help you manage them. You can also visit our section on side effects for more information.