Drug Development

Novartis heads to the finish line with CDK 4/6 blockbuster contender ribociclib


In the final stretch in its journey to regulators, Novartis posted a positive snapshot of pivotal Phase III data on its CDK 4/6 contender ribociclib (LEE011), setting up a likely showdown with Pfizer in treating breast cancer.

The headline figure from ESMO is that ribociclib combined with letrozole reduced the risk of death or progression by 44% among first-line patients compared to letrozole alone, offering further encouragement to the pharma giant that it’s right on track to gaining an approval for this drug next year.

A median progression-free survival benefit could not be established, but the trend is clear. Their study, published in the New England Journal of Medicine, concluded:

After 12 months, the progression-free survival rate was 72.8% (95% confidence interval [CI], 67.3 to 77.6) in the ribociclib group and 60.9% (95% CI, 55.1 to 66.2) in the placebo group; after 18 months, the progression-free survival rate was 63.0% (95% CI, 54.6 to 70.3) and 42.2% (95% CI, 34.8 to 49.5), respectively.

Pfizer was able to land an accelerated approval for palbociclib (sold as Ibrance) in early 2015 with early data demonstrating a 20.2-month PFS rate for Ibrance plus letrozole compared to about 10.2 months for participants receiving only letrozole.

Novartis — which ended their study early on positive data — has several things going in its favor now. The FDA has experience with CDK 4/6 and also granted ribociclib a breakthrough drug designation, flagging the distinct possibility of a fast OK. Barring a nasty surprise, that would put Novartis in line to challenge Pfizer for a blockbuster population. And it would likely get them out into a market they know well ahead of Eli Lilly, which is bullish about its chances with the rival CDK 4/6 drug abemaciclib.

Said principal investigator Gabriel N. Hortobagyi:

“The MONALEESA-2 results show the combination of LEE011 plus letrozole represents a significant step forward in the management of HR+ metastatic breast cancer and, if approved, would be a major addition to the treatment options these patients have. Women living with metastatic breast cancer will be on treatment for the rest of their lives, so it is critical to find treatment options that effectively delay progression.”

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