Update: New drug combination for the second treatment of some HR-positive advanced breast cancers

Relevance: Medium-High

Research Timeline: Post Approval

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What is this update about?

Truqap (capivasertib) plus Faslodex (fulvestrant) can now be used for some people with advanced breast cancer. Faslodex is a type of hormone therapy that is given as an injection. Truqap is a pill taken by mouth; it works by stopping cancer cells from multiplying.  

The FDA approved this combination as a second treatment in people with locally advanced or metastatic HR-positive, HER2-negative breast cancer in the following situations:

• People whose metastatic breast cancer recurred and worsened after receiving hormone therapy.
• People whose early-stage breast cancer recurred while they were on their first treatment or within 12 months of completing it.

Truqap is approved only for people with a tumor that has a mutation in one of three genes: PIK3CA, ATK1 or PTEN. The Foundation One CDx tumor test was also approved by the FDA for use in identifying people who are most likely to benefit from this new combination treatment. 

Study findings

The FDA approval was based on the CAPItello-291 study, which compared Truqap plus Faslodex to Faslodex alone. Just over 700 people with locally advanced or metastatic HR-positive, HER2-negative breast cancer participated in this trial. One group received Truqap plus Faslodex, while the other group received Faslodex alone.

Researchers looked at the time until cancer returned in both groups.

Among all participants:

• Cancer did not return for about 7 months in the group that received Truqap plus Faslodex compared to about 4 months in the group that received Faslodex alone.

When researchers looked at the subset of participants with a tumor mutation in PIK3CA, ATK1 or PTEN:

• Cancer did not return for just over 7 months in the group that received Truqap plus Faslodex compared to 3 months in the group that received Faslodex alone.

At 18 months, overall survival was higher in the group that received Truqap plus Faslodex compared to the group that received Faslodex alone. 

Truqap side effects

Truqap side effects included:

• Rash
• Diarrhea
• High blood sugar
• Hyperglycemia (need insulin and hospitalization)

Among patients who received Truqap, rash and diarrhea were the most common side effects reported. Hyperglycemia (high blood sugar) occurred in 18 percent of these patients.  Grade 3 hyperglycemia (need insulin and hospitalization) or Grade 4 (life-threatening) occurred in 2.8 percent of patients.

Fasting blood glucose and hemoglobin A1C levels should be checked for normal levels before taking Truqap. People taking Truqap who have a medical history of diabetes should be monitored more frequently.