-- Results demonstrating that TYKERB and trastuzumab together resulted in a clinically meaningful extension of progression-free survival (PFS)
-- Combining TYKERB and trastuzumab to attack both the inside and outside of the HER2 receptor may create a more complete HER2 blockade
-- Data demonstrating activity of TYKERB alone despite patients' previous treatment with multiple lines of trastuzumab and chemotherapy
LONDON and PHILADELPHIA, May 16 /PRNewswire-USNewswire/ -- GlaxoSmithKline today announced positive data from the first-ever randomized, multi-center, open label Phase III trial of the combination of two targeted agents, TYKERB and trastuzumab, in women with HER2-positive metastatic breast cancer (1). HER2-positive breast cancer is a particularly aggressive form of cancer that affects approximately 25 to 30 percent of breast cancer patients (2). The study results demonstrated a benefit from the combination. Both treatments target the HER2 (ErbB2) protein but work in different ways (1). Trastuzumab attaches to the outside of the HER2 protein, while TYKERB goes inside the cell to block signals from the HER2 protein for the cancer to grow (3). GlaxoSmithKline Oncology will present these and other new data in breast cancer at the annual American Society of Clinical Oncology (ASCO) meeting in Chicago beginning Friday, May 30th.
"Many women with HER2 positive breast cancer are still very active and living full lives, yet when their disease progresses after trastuzumab and chemotherapy, we have had limited treatment options. Therefore it is important to study options that may eventually help women in their fight against this disease," said lead investigator Joyce O'Shaughnessy, M.D., Baylor-Sammons Cancer Center, Texas Oncology, PA, US Oncology, Dallas, TX. "Effectively attacking HER2 from multiple angles is an exciting and innovative approach, and demonstrates the significant advances being achieved in treating this complex form of breast cancer."
Despite receiving multiple prior lines of anti-cancer therapy, patients who received TYKERB plus trastuzumab in this study experienced:
The study also demonstrated the activity of TYKERB as a single agent in this patient population, with patients on this arm achieving a median progression free survival of 8.1 weeks and an overall clinical benefit rate of 12.4 percent (1).
The clinical synergy of TYKERB and trastuzumab confirms previous observational findings in preclinical studies and previously reported data from a Phase I study. These latest findings confirm the rationale for further research of this combination in earlier lines of therapy in the metastatic setting and in early stage disease. Additional analysis is underway to explore the benefit that TYKERB plus trastuzumab can offer to less heavily pre-treated patients (1).
In this study, 296 patients with HER2 positive breast cancer who had documented progression on trastuzumab treatment in the metastatic setting were eligible to be randomized to receive TYKERB (1000 mg QD) plus trastuzumab (2 mg/kg weekly after 4 mg/kg loading dose) or TYKERB alone (1500 mg QD). Patients were heavily pre-treated and had received a median of six prior anti-cancer regimens. Patients had received a median of three prior lines of trastuzumab (1).
The primary endpoint of the study was progression-free survival, and secondary endpoints included clinical benefit rate (CR+PR+SD greater than or equal to 24 weeks), response rate, and overall survival. If patients progressed on the TYKERB monotherapy arm after four weeks of therapy, they could cross over to receive the combination of TYKERB + trastuzumab. Adverse events were similar in both arms, with Grade 1/2