This is the third in a series about FDA-approved treatments for each sub-type of MBC. Next week I'll post treatments for TNBC and Triple Positive MBC.
The treatment options listed below have been reviewed with a Medical Oncologist at Columbia Presbyterian Hospital in NY. Detailed information about them is available in my book, "The Insider's Guide to Metastatic Breast Cancer" which is available as a paperback and eBook and also a complimentary .pdf. For more information, you are welcome to visit: insidersguidembc.com/about
First-Line Treatment for HER2 Positive, Hormone Receptor Negative Patients in the US and Elsewhere:
A “triplet” combination of Herceptin (Trastuzumab) (or an approved biosimilar, or a subcutaneous injection called Herceptin-Hylecta) along with Perjeta (Pertuzumab) and a Taxane chemotherapy is recommended for first-line treatment unless the patient has congestive heart failure or significantly compromised left ventricular ejection fraction (since Herceptin and Perjeta can cause heart damage). This combination is globally accepted as the initial standard of care.* (see footnote below)
Second Line Treatment for HER2 Positive, Hormone Receptor Negative Patients in the US:
Ideally, second-line therapy should be Kadcyla (TDM-1/Ado-trastuzumab emtansine).
Third-Line Treatment Options and Beyond for HER2 Positive, Hormone Receptor Negative Patients in the US depend upon what treatments were previously taken:
•Kadcyla (if it hasn’t already taken it and the cancer has progressed during or after HER2-targeted therapy).
•Herceptin (or a biosimilar) with chemotherapy.
•Herceptin (or a biosimilar) with Tykerb (Lapatinib).
•Tykerb (Lapatinib) with chemotherapy.
•Herceptin (or a biosimilar) and Perjeta, with or without chemotherapy (if the patient has previously taken Herceptin and chemotherapy without Perjeta).
•Herceptin Hylecta alone (if the patient has received one or more courses of chemotherapy for MBC).
•A clinical trial is also an option.
*First-line treatment for HER2+ MBC patients was further researched in the Phase 2 PERNETTA trial, which randomized 210 previously-untreated HER2+ MBC patients to receive either Herceptin, Perjeta, and chemotherapy (“Group 1”) vs. Herceptin and Perjeta without chemotherapy (“Group 2”). Patients whose disease progressed were given Kadcyla in the second-line setting. Results announced in July 2019 indicated that the 2-year Overall Survival (OS) was similar in both Groups, although the Progression Free Survival (PFS) was better in Group 1. For HER2+, hormone receptor negative patients in Group 1, the median PFS was 22.2 months vs. 8.8 months for Group 2, and the OS was very close – 79.5% vs. 81.1%. The researchers indicated that frontline Herceptin and Perjeta without chemotherapy may be considered for patients with low-to-intermediate tumor burden, especially since treatment toxicity is considerably reduced.
DID YOU KNOW?
Patients with bone metastases should receive a bone-directed therapy such as Xgeva (Denosumab) or Zometa (Zoledronic acid) in addition to their other therapy.
Although very rare, if your cancer has microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) characteristics, and if you’ve progressed on prior therapy and have no satisfactory treatment options, then the PD-1 inhibitor Keytruda (Pembrolizumab) is an FDA-approved option.
If your cancer has a Neurotrophic Receptor Tyrosine Kinase (NTRK) gene fusion without a known acquired resistance mutation, and if you’ve progressed on prior therapy and have no satisfactory treatment options, Larotrectinib (Vitrakvi) - an oral tyrosine kinase inhibitor that acts as an "on" or "off" switch in many cellular functions – is an FDA-approved option. NTRK fusions are quite rare, occurring in only about 0.5–1% of common cancers.