Pfizer works to get 'wait-and-see' doctors on board the Ibrance train

Pfizer's Ibrance, launched in 2015, was the first approved med in the CDK 4/6 class. (Pfizer)

MUNICH—Evidence in favor of the relatively new CDK 4/6 class of breast cancer drugs, which stars Pfizer’s Ibrance, continues to pile up—but it hasn’t yet been enough to convince some doctors to give the meds a try.

“Depending on the data source you look at,” about 60%-plus of women receive a CDK 4/6-based regimen as their first treatment for metastatic HR-positive, HER2-negative breast cancer, Pfizer Oncology Global President Andy Schmeltz said over the weekend at the European Society for Medical Oncology annual meeting. That’s “pretty impressive” for a class that just hit the scene in 2015.

But it also means about 40% of docs are reaching for another therapy, despite “lots of data showing that CDK … plus hormone therapy is a better option,” Schmeltz said. About 20% of patients still receive hormone-based therapy on its own, without Ibrance or newer rivals Kisqali from Novartis or Verzenio from Eli Lilly. And the other 20% receive chemo first.

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While Schmeltz acknowledged that chemo might be the way to go in some cases—it “might be appropriate … to debulk the tumor,” he said, in advance of surgery—but those cases likely don’t add up to 20%.

Instead, the holdout clinicians are likely going with “kind of a wait-and-see approach,” putting it up to Pfizer, and rivals Novartis and Lilly Oncology, to come through and change their minds.

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That approach is one that drugmakers have seen across various areas of oncology for years, Dennis Slamon, M.D., Ph.D., an investigator for a recent Kisqali study, said earlier this year. “It’s going to be interesting” to see how prescribing patterns play out among docs faced with the option of offering [Novartis'] Kisqali earlier in treatment, he said, referencing trends that played out around Roche blockbuster Herceptin, now the standard of care in HER-positive breast cancer.

With that drug, doctors—who “tend to be quite conservative in their approach,” Slamon said—continued to hold back until after further lines of chemo, even after data rolled out supporting its use as a first-up treatment.

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But Pfizer, for one, isn’t planning on waiting around. It’s using sales reps, field-based medical reps, direct-to-consumer advertising and “the full range of medical and marketing efforts” to try to change minds in the oncology community, Schmeltz said.

“In different countries, we customize the mix based on the dynamics locally, but we’re always tweaking and always looking at how to optimize our use of resources,” he added.