Novartis advances rival CDK 4/6 cancer drug to Pfizer's palbociclib

William Sellers, global head of oncology at the Novartis Institutes for Biomedical Research

One of Pfizer's top late-stage prospects is its cancer drug palbociclib, an oral inhibitor of cyclin-dependent kinases (CDK) 4 and 6 that the FDA put in its first group of therapies awarded their "breakthrough" drug designation. But Pfizer ($PFE) is not the only Big Pharma company to view the CDK 4/6 pathway as a likely goldmine in oncology. Novartis ($NVS) has now started a slate of Phase I studies of LEE011, which its researchers are touting as a best-in-class contender.

In lab studies at Novartis Oncology, researchers found that the drug was able to stunt the growth of tumor cells, demonstrating its promise as an add-on combo drug that could prevent resistance to other treatments in the pipeline. For instance, combining LEE011 with an experimental BRAF inhibitor, LGX818, spurred antitumor activity in mouse models for melanoma.

Promising preclinical mouse studies in cancer, of course, are a dime a dozen. But good cancer pathways aren't. Analysts have estimated that palbociclib could be worth anything from $1 billion to $5 billion a year, but everyone sees its potential value as a blockbuster contender. Novartis now plans to come in behind Pfizer with what it believes is a better program.

"Chemistry optimization has led to the discovery of LEE011, which, to our knowledge, is the most selective CDK4/6 inhibitor to date," said Dr. William Sellers, vice president and global head of oncology at the Novartis Institutes for Biomedical Research in Cambridge, MA. "Utilizing the latest cancer genomics data and our knowledge of the role of CDK4/6 activity in the growth of tumor cells, we have identified unique indications and combinations of drugs with LEE011, in which LEE011 demonstrates a robust antitumor activity."

Eli Lilly also has a CDK 4/6 drug in the pipeline, LY2835219. Pfizer may be in the lead now, but it may soon have competition to reckon with.

- here's the press release

Special Report: Top 10 experimental cancer drugs - 2013