#ESMO17: Eli Lilly sets the stage for a CDK 4/6 showdown with Pfizer, Novartis — but not exactly to its advantage

MADRID — Eli Lilly came to ESMO with an eye to distinguishing abemaciclib as it prepares to launch its CDK 4/6 cancer drug against rivals from Novartis and Pfizer. It may have done that, but not exactly as Lilly execs would have liked.

Currently under priority review at the FDA, abemaciclib registered the positive data needed to win over regulators in MONARCH-3. Researchers tracked a 46% reduction in the risk of disease progression in the trial arm including previously untreated women with advanced breast cancer, comparing a combination of abemaciclib added to standard care. There was also a 59% response rate on tumor shrinkage compared to 44% in the control arm provided standard therapy.

The median progression-free survival rate and overall survival numbers aren’t in yet.

That’s all approval-worthy data, but not necessarily the kind of early efficacy results that will intimidate anyone at Pfizer and Novartis worried about market share.

Where it gets troublesome for Eli Lilly, though, is on the side effect data.

Rates of diarrhea and neutropenia were 81.3% and 41.3% with abemaciclib, and 29.8% and 1.9% with placebo, respectively.

David Ricks, Eli Lilly CEO

The investigators are quick to say that the diarrhea is typically fairly low grade and readily managed, but it’s the kind of common effect that could well persuade doctors to prefer either Kisqali or Ibrance for their HR-positive, HER2-negative patients.

That’s not the kind of distinguishing factor you want to raise, especially when you’re late to the game.

Evercore ISI’s Umer Raffat also sent out a note on Sunday highlighting an imbalance of thromboembolic events, which could earn a warning label from the FDA that would give competitors a distinct edge as well.

Not good.

Eli Lilly has asserted that it can make abemaciclib the best-in-class pick among the three CDK 4/6 drugs fielded by three pharma giants with serious sales efforts. And that confidence has built peak sales estimates to close to $2 billion a year. For now.

Researchers also highlighted new evidence that suggests there are patient groups that would benefit more by starting on standard therapy and adding a CDK 4/6 drug as a second-line therapy.

“Now for the first time,we have insights suggesting that patients with certain clinical characteristics may benefit differently from treatment with a CDK 4/6 inhibitor, including the possibility that some patients with a good prognosis may be able to start on endocrine therapy alone,” said lead author Angelo Di Leo. “In such patients, CDK 4/6 inhibitors could potentially be reserved as a next line of treatment for metastatic disease. This idea warrants further study given our data. In our study, nearly one-third of patients had bone metastases only or a tumor relapsing several years after stopping adjuvant endocrine therapy. This is a clinically relevant proportion of patients for whom we may consider delaying use of a CDK 4/6 inhibitor. This may be a more optimal treatment strategy for some patients since it can avoid the toxicity of first line CDK 4/6 inhibitors and save costs.”

Payers won’t overlook that observation.

We won’t have long to wait before things heat up on the market. Lilly nabbed a priority review for this drug in July, setting up a final decision by January.

Lilly needs a steady stream of significant new drug approvals if new CEO Dave Ricks expects to keep its investors happy. The FDA have helped out by putting baricitinib back on track, but we won’t know that for sure until next year.

Image credit: ESMO

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Sr. Manager, Regulatory Affairs, CMC
CytomX Therapeutics San Francisco, CA
Marketing Associate - Demand Generation
Catalytic Data Science Charleston, SC
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Flatiron Health New York City or San Francisco

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