TRIO-18-Studie

Allgemeines

The cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with letrozole versus letrozole alone as first-line treatment of oestrogen receptor-positive, HER2-negative, advanced breast cancer (PALOMA-1/TRIO-18): a randomised phase 2 study SUMMARY: The U. S. Food and Drug Administration on February 3, 2015 granted accelerated approval to IBRANCE® (Palbociclib), for use in combination with FEMARA® (Letrozole), for the treatment of postmenopausal women with Estrogen Receptor (ER)-positive, Human Epidermal growth factor Receptor 2 (HER2) negative advanced Breast Cancer, as initial endocrine-based therapy for their metastatic disease. Approximately 60% of the breast tumors express Estrogen Receptors and these patients are often treated with anti-estrogen therapy as first line treatment. Cyclin Dependent Kinases (CDK) play a very important role to facilitate orderly and controlled progression of the cell cycle. Genetic alterations in these kinases and their regulatory proteins have been implicated in various malignancies. IBRANCE® is a reversible, oral, small molecule inhibitor of Cyclin Dependent Kinases (CDK) 4/6 and is the first CDK inhibitor approved by the FDA. This agent in pre-clinical studies was noted to reduce cellular proliferation of Estrogen Receptor positive Breast Cancer cell lines by blocking progression of cells from G1 into S phase of the cell cycle and was also noted to be synergistic with anti-estrogens. The approval of IBRANCE® was based on an open-label, randomized, multicenter, phase II study which included postmenopausal women with ER-positive, HER2-negative, advanced (locally advanced or metastatic) Breast Cancer who had not received previous systemic treatment for advanced disease. This trial enrolled and randomly assigned 165 patients, to receive either IBRANCE® 125 mg PO daily for 21 consecutive days, followed by 7 days off treatment) plus FEMARA® (2.5 mg PO daily continuously throughout the 28-day cycle (N=84) or FEMARA® alone (N=81). Among the 165 patients, 43% had received chemotherapy and 33% had received anti-hormonal therapy as a neoadjuvant or adjuvant treatment. Fortynine percent (49%) of patients had no prior systemic therapy in the neoadjuvant or adjuvant setting. The majority of patients (98%) had stage IV disease, 48% had visceral disease and 17% had bone only disease. The primary endpoint was investigator-assessed Progression Free Survival. The median PFS was 20.2 months in the IBRANCE® plus FEMARA® group and 10.2 months in the FEMARA® alone group (HR=0.488, P=0•0004). In patients with measurable disease, the Overall Response rate was higher in the IBRANCE® plus FEMARA® group compared to the FEMARA® alone group (55% versus 39%, P=0.04). The median duration of response for those who had a partial or complete response was 20.3 months with a combination of IBRANCE® plus FEMARA® vs 11.1 months with FEMARA® alone. The most common Grade 3–4 adverse events in the IBRANCE® plus FEMARA® group were neutropenia and leucopenia but without any cases of neutropenic fever. Unlike chemotherapy, the duration of neutropenia was brief with rapid recovery of blood counts. The authors concluded that the addition of IBRANCE® to FEMARA® significantly improved Progression Free Survival in women with advanced Estrogen Receptor positive and HER2-negative breast cancer. This combination may therefore be a reasonable treatment option in this patient group, soon after metastatic disease is diagnosed. Biomarkers expression (cyclinD1 amplification and/or loss of p16) had no impact on outcomes suggesting that the biomarker for IBRANCE® may be the Estrogen Receptor itself, rather than CDK4/6 kinases. Finn RS, Crown JP, Lang I, et al. Lancet Oncol 2015; 16:25-35

Fragestellung

Verbessert Palbociclib mit Letrezol das Therapieergebnis von  Frauen mit metastasiertem Rezeptor-positivem, Her2neu-negativem Brustkrebs gegenüber der Behandlung mit Letrezol allein?

Ergebnis

Mechanismus

Palbociclib ist ein oraler CDK 4/6 - Inhibitor. CDK ist eine Cyclin - abhängige Kinase mit zentraler Rolle in der Mitose bei luminal-Typ Mammakarzinomen. Palbociclib hemmt die Progression von G1- in die S-Phase der Mitose.

Patienten

165 postmenopausale mit metastasiertem ER+/Her2- Brustkrebs.

Arm 1

Palbociclib und Letrezol

Letrezol