Adding the CDK4/6 inhibitor abemaciclib to Faslodex (fulvestrant) is a promising way to treat patients with an advanced breast cancer who experienced a relapse or had their disease progress after endocrine therapy, clinical trial results indicate.
The MONARCH Phase 3 trial covered patients with hormone receptor (HR)-positive, HER2-negative breast cancer. The combination therapy significantly improved patients’ time to disease progression or death, compared with patients who received Faslodex plus a placebo, according to abemaciclib’s maker, Lilly Oncology.
“We are excited about the outcome of our first Phase 3 study for abemaciclib. These data are an important milestone in our goal of bringing abemaciclib to patients with advanced breast cancer, and we look forward to our upcoming conversations with regulators,” Levi Garraway, MD, PhD, senior vice president of global development and medical affairs at Lilly Oncology, said in a news release. “This is another example of Lilly’s commitment to delivering breakthrough treatments and improving outcomes for patients with cancer.”
Lilly is conducting several MONARCH trials in addition to the MONARCH Phase 3 study that has been completed.
The global MONARCH 2 study (NCT02107703) is a randomized, double-blind, placebo-controlled trial. Its objective is to assess the safety and effectiveness of abemaciclib and Faslodex, versus a placebo and Faslodex, in patients with HR-positive, HER-negative advanced breast cancer.
The trial has enrolled 669 patients who had disease progression within 12 months of receiving endocrine therapy before or after breast surgery, or while receiving first-line endocrine treatment for metastatic disease — one that had spread.
Participants were randomized to receive continuous oral abemaciclib, or a placebo, twice daily, in combination with Faslodex, until there was disease progression or unacceptable toxicity to the patient. The study has met its primary endpoint, showing significant improvement in progression-free survival in patients who took abemaciclib and Faslodex, compared with those who took a placebo and Faslodex.
The most common adverse events were diarrhea, nausea, fatigue, and low levels of immune cells called neutrophils.
Complete results will be presented at an upcoming medical meeting, Lilly said.
The company plans to submit a New Drug Application asking the U.S Food and Drug Administration to approve abemaciclib plus Faslodex for patients with HR-positive, HER2-negative advanced breast cancer.
It also plans to submit a New Drug Application for abemaciclib as a stand-alone treatment for previously treated HR-positive, HER2-negative metastatic breast cancer patients. It based that decision on the results of the Phase 2 MONARCH 1 study (NCT02102490).
Abemaciclib is also being assessed in another Phase 3 trial, the MONARCH 3 study (NCT02246621). It is evaluating abemaciclib in combination with a nonsteroid-based aromatase inhibitor in HR-positive, HER2-negative advanced breast cancer patients.
In addition, Lilly is conducting the Phase 2 trial monarcHER (NCT02675231) trial. It is assessing the safety and effectiveness of combining abemaciclib and Herceptin (trastuzumab), with or without Faslodex, in women with HR-positive, HER2-negative advanced or metastatic breast cancer. The study is currently recruiting participants.