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Study: Breast cancer outcomes improved with CDK4/6 inhibitor treatment

A study showed that people with metastatic breast cancer who took an oral drug known as a CDK4/6 inhibitor combined with hormone therapy did better than people who took hormone therapy alone. The drug combination improved the length of time before cancer worsened or returned. After six years of treatment, people who took this drug combination lived longer compared to those who took hormone therapy alone. (Posted 4/5/23)

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RELEVANCE

Most relevant for: People with HR-positive HER2-negative advanced breast cancer.

It may also be relevant for:

  • people with ER/PR + cancer
  • men with breast cancer

Relevance: High

Strength of Science: Medium-High

Research Timeline: Post Approval

Relevance rating details

What was the research about?

A large research study known as PALOMA-3 looked at how well a drug called Ibrance (palbociclib) works when combined with hormone therapy (fulvestrant) for people with breast cancer that was hormone sensitive (). In 2019, researchers shared early results from the study, which seemed to show that some people who received the two drugs together did better than people who received hormone treatment alone. However, these results were too early for researchers to say for certain that the drug combination worked better than hormone therapy alone.  

This follow-up report from 2022 looked at overall survival (how long participants lived) for a longer period of time. The report also looked at whether some groups of people benefitted more from the drug combination.

Study findings

Researchers looked at results for all participants and for different subgroups of participants.

All participants

In this updated report, overall survival continued to be better for people who were treated with Ibrance plus fulvestrant compared to people treated with fulvestrant alone:

  • 35 months for people on Ibrance plus fulvestrant
  • 28 months for people on fulvestrant alone

While the combination of fulvestrant plus Ibrance improved overall survival, the difference—a benefit of seven months at six years—was not statistically significant. (The overall survival reported in 2019 was the same for both groups.)

The benefit for participants who did not previously have chemotherapy
Among people who had not received prior chemotherapy, overall survival at 6 years was 40 months for people on Ibrance plus fulvestrant compared to 30 months for people on fulvestrant alone, a benefit of 10 months. This result was statistically significant.

Overall survival
  fulvestrant alone Ibrance plus fulvestrant
Full group 28 months 35 months
No chemotherapy 30 month 40 months

 

 

 

Expert Guidelines

The National Comprehensive Cancer Network (NCCN) guidelines for the treatment of advanced or metastatic ER-positive breast cancer include the following:

Genetic testing

  • All people diagnosed with metastatic breast cancer meet guidelines for genetic counseling and testing. 

NCCN preferred treatment options

The NCCN lists the following preferred treatments for metastatic ER-positive and HER2-negative breast cancer:

  • for people with or mutations:
    • Lynparza () or () for people with an inherited BRCA1 or BRCA2 mutation. 
  • therapy
    • A combination of hormonal therapy (aromatase inhibitor or Fulvestrant) + targeted therapy with a CDK4/6 inhibitor:
      •  abemaciclib (Verzenio), palbocicib (Ibrance) or ribociclib (Kisqali). 
  • For second-, third- or later lines of therapy:
    • A combination of hormonal therapy (aromatase inhibitor or Fulvestrant) plus targeted therapy with a CDK4/6 inhibitor for people who have not previously received a CDK4/6 inhibitor.
    • Enhertu (trastuzumab deruxtecan) for people with HER2-low ( 1+ or HER2 2+) tumors, who received chemotherapy for metastatic disease and whose cancer no longer responds to hormonal therapy.
    • Piqray (apelisib) for cancers that test positive for a PIK3CA mutation.
    • Oserdu (elacestrant) for HR-positive, HER2-negative cancers that test positive for an ESR1 mutation.
    • Lynparza (olaparib) or Talzenna (talazoparib) for BRCA1/BRCA2 for tumors with a BRCA1 or BRCA2 mutation.
    • A combination of everolimus and hormonal therapy.
    • Hormonal therapy alone.
    • Trodelvy (sacituzumab govitecan-hziy) for HR-positive, HER2-negative after prior treatment, including hormone therapy, a CDK4/6 inhibitor and at least two lines of chemotherapy (including a taxane).

Updated: 03/21/2023

Peer Support

The following organizations offer peer support services for people with or at high risk for breast cancer:

Updated: 05/07/2024