Truqap/Faslodex Delays Time to Breast Cancer Progression, Next Therapy

Patients with HR-positive, HER2-negative locally advanced or metastatic breast cancer tended to live longer until the time to second progression (PFS2; when the cancer worsens or spreads a second time) when Truqap (capivasertib) was added to Faslodex (fulvestrant), compared with those given Faslodex alone.

These results from the phase 3 CAPItello-291 trial included patients who had at least 1 PIK3CA, AKT1 or PTEN alteration. Data were presented at the 2024 ESMO Breast Cancer Congress.

The median PFS2 among 355 patients treated with Truqap plus Faslodex was 14.7 months, compared to 12.5 months in 353 patients given a placebo (inactive drug) plus Faslodex.

In the PIK3CA/AKT1/PTEN-altered population, the median PFS2 was 15.5 months in the Truqap arm (155 patients) compared with 10.8 months for the placebo arm (134 patients).

Furthermore, Truqap plus Faslodex delayed time to first subsequent chemotherapy (TFSC) in the overall and PIK3CA/AKT1/PTEN-altered populations. In the overall population, the median TFSC was 11 months for the Truqap plus Faslodex arm compared with 6.8 months for the placebo plus Faslodex arm.

In the PIK3CA/AKT1/PTEN-altered populations, the median TFSC was 11 months in the Truqap group compared with six months in the placebo group.

READ MORE: Truqap Plus Faslodex Boosts Breast Cancer Outcomes, Quality of Life

“[These] data demonstrates that [Truqap] with [Faslodex] provided long-lasting benefits retained through PFS2 in patients with hormone receptor–positive, HER2-negative advanced disease who progressed on or after an endocrine-based regimen,” Dr. Hope S. Rugo stated in a presentation of the data.

Rugo serves as a professor in the Department of Medicine, Hematology/Oncology, director of Breast Oncology and Clinical Trials Education, and the medical director of Cancer Infusion Services at the University of California, San Francisco, Helen Diller Comprehensive Cancer Center.

In November 2023, the Food and Drug Administration approved Truqap plus Faslodex for the treatment of patients with HR-positive/HER2-negative, locally advanced or metastatic breast cancer harboring one or more PIK3CA/AKT1/PTEN alterations following progression on at least one endocrine-based regimen in the metastatic setting or recurrence on or within 12 months of completing adjuvant therapy.

This regulatory approval was based on previously reported data from CAPItello-291, which showed that Truqap plus Faslodex improved progression-free survival (time patients live before disease worsening) compared with Truqap alone in the overall population and the PIK3CA/AKT1/PTEN-altered population.

In the overall population, patients in the Truqap arm achieved a median progression-free survival of 7.2 months compared with 3.6 months for patients receiving placebo plus Truqap. In patients harboring alterations in the AKT pathway, the median progression-free survival was 7.3 months for the Truqap regimen compared with3.1 months for the placebo regimen.

The CAPItello-291 trial enrolled men and pre- or post-menopausal women with locally advanced or metastatic, hormone receptor–positive, HER2-negative breast cancer who experienced recurrence or progression during or within 12 months of completing adjuvant treatment with an aromatase inhibitor (AI), or during prior AI therapy for advanced breast cancer. Additionally, eligible patients must have undergone no more than two lines of prior endocrine therapy for advanced disease; no more than one line of chemotherapy; and no prior treatment with selective estrogen receptor degraders (SERDs), mTOR inhibitors, PI3K inhibitors or AKT inhibitors. However, prior treatment with CDK4/6 inhibitors was permitted.

Patients were randomly assigned to receive Truqap plus Faslodex, or placebo plus Faslodex. Patient data was analyzed based on factors included liver metastases, treatment with a prior CDK4/6 inhibitor and region.

The dual primary end points of the study were progression-free survival in the overall population and in the PIK3CA/AKT1/PTEN-altered population. Key secondary end points included overall survival (time from treatment until death of any cause), overall response rate (percentage of patients whose disease shrunk or disappeared from treatment) and PFS2 in both patient populations. TFSC was an exploratory end point.

Additional data showed that among patients in the overall population receiving Truqap/Faslodex, 70.1% of patients had disease progression, and 67.0% of patients went on to receive subsequent treatment. First subsequent treatment consisted of cytotoxic chemotherapy (43.1%), hormone therapy (22.3%) and targeted therapy (13.0%). In the placebo arm, 79.6% of patients had disease progression, and 74.8% went on to receive a first subsequent treatment, including cytotoxic chemotherapy (47.9%), hormone therapy (23.5%) or targeted therapy (18.1%).

Among patients in the PIK3CA/AKT1/PTEN-altered population treated with Truqap/Faslodex, 74.2% of patients had disease progression, and 69% went on to receive a first subsequent treatment, including cytotoxic chemotherapy (43.2%), hormone therapy (23.9%) and targeted therapy (11.6%). In the placebo group, 80.6% of patients experienced disease progression, and 78.4% received a first subsequent therapy, including cytotoxic chemotherapy (50.0%), hormone therapy (25.4%) or targeted therapy (21.6%).

Furthermore, in the overall population, treatments given in any subsequent line of therapy included cytotoxic chemotherapy (Truqap/Faslodex, 56.1%; placebo/Faslodex, 61.2%), hormone therapy (27.6%; 30.3%) and targeted therapy (18.9%; 25.8%). In the PIK3CA/AKT1/PTEN-altered population, treatments given in any subsequent line of therapy, included cytotoxic chemotherapy (60.0%; 62.7%), hormone therapy (27.7%; 35.1%) and targeted therapy (16.8%; 32.1%).

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