PracticeUpdate: Haematology & Oncology

CONFERENCE COVERAGE

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European Society of Medical Oncology 2016 Congress 7–11 OCTOBER 2016 • COPENHAGEN, DENMARK

Billed as the leading oncology event in Europe, the European Society of Medical Oncology 2016 Congress hosted 19,000 participants, including oncology professionals across varying fields and disciplines. In this issue of PracticeUpdate Haematology & Oncology , we bring you our picks from a very packed scientific programme, including the latest clinical investigations into targeted therapies in oncology.

Improvement in progression-free survival with ribociclib + letrozole may represent a paradigm shift in advanced breast cancer Adding the CDK4/6 inhibitor

A s reported by Gabriel Hor- tobagyi, MD, of the Univer- sity of Texas MD Anderson Cancer Center, the combination of ribociclib + letrozole Houston led to a 44% improvement in progression- free survival when used as a first-line treatment combination. He noted, “This was the definitive study to demonstrate the superiority of the combination of ribociclib + letrozole over letrozole alone.” A total of 668 postmenopausal women with hormone receptor- positive, HER2-negative advanced breast cancer, who had not under- gone prior systemic treatment, were randomised to ribociclib (600 mg daily, 3 weeks on/1 week off) + letrozole (2.5 mg daily, continuous), or letrozole + placebo. A 44% improvement was observed in the primary objective of progres- sion-free survival versus placebo in

hormone receptor-positive, HER2- negative advanced breast cancer who had received no prior therapy for advanced breast cancer. Giuseppe Curigliano, MD, of the European Institute of Oncology, Milan, Italy, commented, “I believe the results of this study are significant because now we have a newCDK4/6 inhibitor for patients with oestrogen receptor-positive metastatic breast cancer, in addition to palbociclib (already FDA approved) and abe- maciclib (under development).” He added, “The addition of riboci- clib to letrozole raises the rate of tox- icity, but overall, if we evaluate the magnitude of clinical benefit, adding ribociclib is clearly beneficial.” Dr Curigliano said, “Further stud- ies of ribociclib should examine bio- markers to better identify patients who would respond to the addition of the drug to letrozole.”

Serious adverse events were reported by fewer than 5% of patients in both groups. Other adverse events were significantly more common in patients taking ribociclib. Fifty-nine percent of patients in the ribociclib arm suffered fromneutropenia versus 1% in the placebo arm. Leukopenia occurred in 21% vs 1%, lymphopenia in 7% vs 1%, respectively. Patients who received ribociclib exhibited higher incidences of elevated ala- nine aminotransferase and aspartate aminotransferase. Too few patients in the study died to enable a reliable analysis of the impact of ribociclib therapy on overall survival. Dr Hortobagyi concluded that the combination of ribociclib and letrozole prolonged progression- free survival significantly and was well tolerated vs letrozole alone in postmenopausal women with

patients taking ribociclib (hazard ratio 0.556, P = 0.00000329). Median progression-free survival was 14.7 months in patients tak- ing placebo but was not reached in those taking ribociclib at data cutoff. “The results represent compelling proof of principle,” said Dr Horto- bagyi, “and suggest a paradigm shift in metastatic, hormone receptor-positive breast cancer. They also suggest that testing combinations of ribociclibwith other inhibitors of various signalling pathways might lead to additional progress in themanagement of several subtypes of breast cancer.” Patients who demonstrated measurable disease at baseline exhibited a significantly higher objective response rate to ribociclib + letrozole than to letrozole alone (53% vs 37%; P = 0.00028), as well as a better rate of clinical benefit rate (80% vs 72%, P = 0.02).

ribociclib to letrozole therapy significantly

improved progression-free survival in postmenopausal women with hormone receptor-positive advanced breast cancer, finds the first interim analysis of data from the randomised, placebo- controlled, double-blind MONALEESA2 reported at ESMO.

PRACTICEUPDATE HAEMATOLOGY & ONCOLOGY