A trial of ribociclib alongside letrozole for advanced breast cancer (MONALEESA 2)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 3

This trial was for women whose breast cancer had come back in the same place or had spread to another part of the body (advanced breast cancer).

Their cancer also had to be:

hormone receptor positive
HER2 negative

Hormone receptor positive means that breast cancer cells have receptors Open a glossary item for the hormones oestrogen and progesterone. HER2 negative is when cancer cells don’t have receptors for the human epidermal growth factor (HER2) .

More about this trial

Hormone therapy is often used to treat hormone receptor positive breast cancer. Letrozole (Femara) is one type of hormone therapy. Doctors use it as a treatment for breast cancer in women who are post menopausal Open a glossary item .

Ribociclib (LEE011) is a type of targeted cancer drug called a cancer growth blocker. It stops signals that cancer cells use to divide and grow.

The researchers wanted to find out if ribociclib alongside letrozole helps women with advanced breast cancer. In this trial, women had 1 of the following:

ribociclib and letrozole
dummy drug (placebo ) and letrozole

The aims of this trial were to:

find out how well ribociclib and letrozole work as a treatment
learn more about the side effects
find out how this treatment affects the women’s quality of life

Summary of results

The trial team concluded that ribociclib alongside letrozole helps women with advanced breast cancer.

This was a phase 3 trial. 668 women with advanced breast cancer took part. Everyone had hormone receptor positive breast cancer and HER2 negative breast cancer.

This was a randomised trial. Women were put into 1 of the following treatment groups by computer:

334 women had ribociclib and letrozole
334 women had a dummy drug and letrozole

Neither they nor their doctor could choose which group they were in.

MONALEESA 2 Results Diagram

Everyone had treatment for as long as their cancer stayed the same and didn’t get worse. When their cancer got worse (disease progression Open a glossary item ), women stopped having treatment.

Some people were still having treatment at the time the study team looked at the results. So, the team looked at how well ribociclib worked for all women after 18 months of treatment.

To do this, doctors looked at the number of women who had no signs of their cancer getting worse after 18 months of treatment. This is called progression free survival. They found it was:

around 6 out of every 10 women (63%) in the ribociclib and letrozole group
around 4 out of every 10 women (42%) in the dummy drug and letrozole group

The team also looked at the most common side effects women had. They were:

a drop in the number of white blood cells causing an increased risk of infection (neutropenia)
feeling sick
infection
fatigue
diarrhoea

The team found that women in the ribociclib and letrozole group had worse side effects than women in the dummy drug and letrozole group.

So, the trial team concluded that ribociclib alongside letrozole helps women with advanced breast cancer. They will continue to look at the results until all women finish their treatment.

We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.