Dual Blockade of HER-2 Provides a Greater Magnitude of Benefit in Patients With Hormone-Negative Versus Hormone-Positive Breast Cancer

Fulvestrant and trastuzumab in patients with luminal HER2-positive advanced breast cancer (ABC): an Italian real-world experience (HERMIONE 9)

PURPOSE

The most appropriate therapy for HR + /HER2-positive (HER2 +) advanced breast cancer (ABC) is a matter of debate. Co-targeting of both receptors represents an attractive strategy to overcome the cross-talk between them.

METHODS

The HERMIONE 9 is an observational retrospective multicentric study which aimed to describe the clinical outcome of patients with HR + /HER2 + ABC who received the combination of Fulvestrant (F) and Trastuzumab (T) as part of their routine treatment at 10 Italian Institutions.

RESULTS

Eighty-seven patients were included. Median age was 63 (range, 35-87) years. The median number of previous treatments was 3 (range, 0-10) and F and T were administered as ≥ 3rd line in 67 patients. Among the 86 evaluable patients, 6 (6.9%) achieved CR, 18 (20.7%) PR, and 44 (50.6%) had SD ≥ 24 weeks with an overall CBR of 78.2%. At a median follow-up of 33.6 months, mPFS of the entire cohort was 12.9 months (range, 2.47-128.67). No difference was observed in mPFS between patients treated after progression or as maintenance therapy (mPFS 12.9 and 13.9 months in 64 and 23 patients, respectively), neither considering the number of previous treatment lines (≤ 3 or < 3).

CONCLUSION

The combination of F and T was active in this cohort at poor prognosis and deserves further investigations possibly in combination with pertuzumab in patients with high ER expression.

Phase III, Randomized Study of Dual Human Epidermal Growth Factor Receptor 2 (HER2) Blockade With Lapatinib Plus Trastuzumab in Combination With an Aromatase Inhibitor in Postmenopausal Women With HER2-Positive, Hormone Receptor–Positive Metastatic Breast Cancer: Updated Results of ALTERNATIVE

PURPOSE

Human epidermal growth factor receptor 2 (HER2) targeting plus endocrine therapy (ET) improved clinical benefit in HER2-positive, hormone receptor (HR)–positive metastatic breast cancer (MBC) versus ET alone. Dual HER2 blockade enhances clinical benefit versus single HER2 blockade. The ALTERNATIVE study evaluated the efficacy and safety of dual HER2 blockade plus aromatase inhibitor (AI) in postmenopausal women with HER2-positive/HR-positive MBC who received prior ET and prior neo(adjuvant)/first-line trastuzumab (TRAS) plus chemotherapy. This updated article reflects minor numerical corrections in some secondary efficacy analyses that resulted from programming errors and that do not change the major conclusions of the study.

METHODS

Patients were randomly assigned (1:1:1) to receive lapatinib (LAP) plus TRAS plus AI, TRAS plus AI, or LAP plus AI. Patients for whom chemotherapy was intended were excluded. The primary end point was progression-free survival (PFS; investigator assessed) with LAP plus TRAS plus AI versus TRAS plus AI. Secondary end points were PFS (comparison of other arms), overall survival (OS), overall response rate (ORR), clinical benefit rate (CBR), and safety.

RESULTS

Three hundred fifty-five patients were included in this analysis: LAP plus TRAS plus AI (n = 120), TRAS plus AI (n = 117), and LAP plus AI (n = 118). Baseline characteristics were balanced. The study met its primary end point; superior PFS was observed with LAP plus TRAS plus AI versus TRAS plus AI (median PFS, 11 v 5.6 months; hazard ratio, 0.62 [95% CI, 0.45 to 0.88]; P = .0063). A consistent PFS benefit was observed in predefined subgroups. ORR, CBR, and OS also favored LAP plus TRAS plus AI. The median PFS with LAP plus AI versus TRAS plus AI was 8.3 versus 5.6 months (hazard ratio, 0.85 [95% CI, 0.62 to 1.17]; P = .3159). Common adverse events (AEs; ≥ 15%) with LAP plus TRAS plus AI, TRAS plus AI, and LAP plus AI were diarrhea (69%, 9%, and 51%, respectively), rash (36%, 2%, and 28%, respectively), nausea (22%, 9%, and 22%, respectively), and paronychia (30%, 0%, and 15%, respectively), mostly grade 1 or 2. Serious AEs were reported similarly across the 3 groups, and AEs leading to discontinuation were lower with LAP plus TRAS plus AI.

CONCLUSION

Dual HER2 blockade with LAP plus TRAS plus AI showed superior PFS benefit versus TRAS plus AI in patients with HER2-positive/HR-positive MBC. This combination offers an effective and safe chemotherapy-sparing alternative treatment regimen for this patient population.

Tribody [(HER2)2xCD16] Is More Effective Than Trastuzumab in Enhancing γδ T Cell and Natural Killer Cell Cytotoxicity Against HER2-Expressing Cancer Cells

An enhanced expression of human epidermal growth factor receptor 2 (HER2, ErbB2) often occurs in an advanced stage of breast, ovarian, gastric or esophageal cancer, and pancreatic ductal adenocarcinoma (PDAC). Commonly, HER2 expression is associated with poor clinical outcome or chemoresistance in ovarian and breast cancer patients. Treatment with humanized anti-HER2 monoclonal antibodies, such as trastuzumab or pertuzumab, has improved the outcome of patients with HER2-positive metastatic gastric or breast cancer, but not all patients benefit. In this study, the bispecific antibody [(HER2)₂xCD16] in the tribody format was employed to re-direct CD16-expressing γδ T lymphocytes as well as natural killer (NK) cells to the tumor-associated cell surface antigen HER2 to enhance their cytotoxic anti-tumor activity. Tribody [(HER2)₂xCD16] comprises two HER2-specific single chain fragment variable fused to a fragment antigen binding directed to the CD16 (FcγRIII) antigen expressed on γδ T cells and NK cells. Our results revealed the superiority of tribody [(HER2)₂xCD16] compared to trastuzumab in triggering γδ T cell and NK cell-mediated lysis of HER2-expressing tumor cells, such as PDAC, breast cancer, and autologous primary ovarian tumors. The increased efficacy of [(HER2)₂xCD16] can be explained by an enhanced degranulation of immune cells. Although CD16 expression was decreased on γδ T cells in several PDAC patients and the number of tumor-infiltrating NK cells and γδ T cells was impaired in ovarian cancer patients, [(HER2)₂xCD16] selectively enhanced cytotoxicity of cells from these patients. Here, unique anti-tumor properties of tribody [(HER2)₂xCD16] are identified which beyond addressing HER2 overexpressing solid tumors may allow to treat with similar immunoconstructs combined with the adoptive transfer of γδ T cells and NK cells refractory hematological malignancies. A major advantage of γδ T cells and NK cells in the transplant situation of refractory hematological malignancies is given by their HLA-independent killing and a reduced graft-versus-host disease.

Phase III, Randomized Study of Dual Human Epidermal Growth Factor Receptor 2 (HER2) Blockade With Lapatinib Plus Trastuzumab in Combination With an Aromatase Inhibitor in Postmenopausal Women With HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer: ALTERNATIVE

Purpose Human epidermal growth factor receptor 2 (HER2) targeting plus endocrine therapy (ET) improved clinical benefit in HER2-positive, hormone receptor (HR)-positive metastatic breast cancer (MBC) versus ET alone. Dual HER2 blockade enhances clinical benefit versus single HER2 blockade. The ALTERNATIVE study evaluated the efficacy and safety of dual HER2 blockade plus aromatase inhibitor (AI) in postmenopausal women with HER2-positive/HR-positive MBC who received prior ET and prior neo(adjuvant)/first-line trastuzumab (TRAS) plus chemotherapy. Methods Patients were randomly assigned (1:1:1) to receive lapatinib (LAP) + TRAS + AI, TRAS + AI, or LAP + AI. Patients for whom chemotherapy was intended were excluded. The primary end point was progression-free survival (PFS; investigator assessed) with LAP + TRAS + AI versus TRAS + AI. Secondary end points were PFS (comparison of other arms), overall survival, overall response rate, clinical benefit rate, and safety. Results Three hundred fifty-five patients were included in this analysis: LAP + TRAS + AI (n = 120), TRAS + AI (n = 117), and LAP + AI (n = 118). Baseline characteristics were balanced. The study met its primary end point; superior PFS was observed with LAP + TRAS + AI versus TRAS + AI (median PFS, 11 v 5.7 months; hazard ratio, 0.62; 95% CI, 0.45 to 0.88; P = .0064). Consistent PFS benefit was observed in predefined subgroups. Overall response rate, clinical benefit rate, and overall survival also favored LAP + TRAS + AI. The median PFS with LAP + AI versus TRAS + AI was 8.3 versus 5.7 months (hazard ratio, 0.71; 95% CI, 0.51 to 0.98; P = .0361). Common adverse events (AEs; ≥ 15%) with LAP + TRAS + AI, TRAS + AI, and LAP + AI were diarrhea (69%, 9%, and 51%, respectively), rash (36%, 2%, and 28%, respectively), nausea (22%, 9%, and 22%, respectively), and paronychia (30%, 0%, and 15%, respectively), mostly grade 1 or 2. Serious AEs were reported similarly across the three groups, and AEs leading to discontinuation were lower with LAP + TRAS + AI. Conclusion Dual HER2 blockade with LAP + TRAS + AI showed superior PFS benefit versus TRAS + AI in patients with HER2-positive/HR-positive MBC. This combination offers an effective and safe chemotherapy-sparing alternative treatment regimen for this patient population.

Phase III, Randomized Study of Dual Human Epidermal Growth Factor Receptor 2 (HER2) Blockade With Lapatinib Plus Trastuzumab in Combination With an Aromatase Inhibitor in Postmenopausal Women With HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer: ALTERNATIVE

Purpose Human epidermal growth factor receptor 2 (HER2) targeting plus endocrine therapy (ET) improved clinical benefit in HER2-positive, hormone receptor (HR)-positive metastatic breast cancer (MBC) versus ET alone. Dual HER2 blockade enhances clinical benefit versus single HER2 blockade. The ALTERNATIVE study evaluated the efficacy and safety of dual HER2 blockade plus aromatase inhibitor (AI) in postmenopausal women with HER2-positive/HR-positive MBC who received prior ET and prior neo(adjuvant)/first-line trastuzumab (TRAS) plus chemotherapy. Methods Patients were randomly assigned (1:1:1) to receive lapatinib (LAP) + TRAS + AI, TRAS + AI, or LAP + AI. Patients for whom chemotherapy was intended were excluded. The primary end point was progression-free survival (PFS; investigator assessed) with LAP + TRAS + AI versus TRAS + AI. Secondary end points were PFS (comparison of other arms), overall survival, overall response rate, clinical benefit rate, and safety. Results Three hundred fifty-five patients were included in this analysis: LAP + TRAS + AI (n = 120), TRAS + AI (n = 117), and LAP + AI (n = 118). Baseline characteristics were balanced. The study met its primary end point; superior PFS was observed with LAP + TRAS + AI versus TRAS + AI (median PFS, 11 v 5.7 months; hazard ratio, 0.62; 95% CI, 0.45 to 0.88; P = .0064). Consistent PFS benefit was observed in predefined subgroups. Overall response rate, clinical benefit rate, and overall survival also favored LAP + TRAS + AI. The median PFS with LAP + AI versus TRAS + AI was 8.3 versus 5.7 months (hazard ratio, 0.71; 95% CI, 0.51 to 0.98; P = .0361). Common adverse events (AEs; ≥ 15%) with LAP + TRAS + AI, TRAS + AI, and LAP + AI were diarrhea (69%, 9%, and 51%, respectively), rash (36%, 2%, and 28%, respectively), nausea (22%, 9%, and 22%, respectively), and paronychia (30%, 0%, and 15%, respectively), mostly grade 1 or 2. Serious AEs were reported similarly across the three groups, and AEs leading to discontinuation were lower with LAP + TRAS + AI. Conclusion Dual HER2 blockade with LAP + TRAS + AI showed superior PFS benefit versus TRAS + AI in patients with HER2-positive/HR-positive MBC. This combination offers an effective and safe chemotherapy-sparing alternative treatment regimen for this patient population.