Analyst Notes: Ibrance launch will change the way HER2-negative/HR-positive breast cancer is treated, argue KOLs

Pfizer's Ibrance (palbociclib) received accelerated approval from the FDA in February based on the strength of Phase II data from the PALOMA-1 trial. The agent, a CDK 4/6 inhibitor, is approved in combination with Novartis' Femara (letrozole) as a first-line therapy for postmenopausal women with HER2-negative/oestrogen receptor-positive advanced breast cancer as initial endocrine-based therapy for their metastatic disease.

More good news came in April when the Phase III PALOMA-3 study, which evaulated Ibrance in combination with AstraZeneca's Faslodex (fulvestrant) in the second-line setting, was stopped early due to an improvement in progression-free survival in patients with HER2-negative/HR-positive, metastatic breast cancer.

Insight, Analysis & Views

Although Ibrance has only been on the market for a few months, and the impact that the drug will have on treating HER2-negative/HR-positive breast cancer is unclear, key opinion leaders (KOLs) believe that its approval as a first-line therapy and positive results in the second-line setting are likely to transform the way HER2-negative/HR-positive breast cancer is treated.

Leading KOLs interviewed for a new report – Breast Cancer: KOL Insight; New CDK inhibitors and PARP inhibitors will transform treatment paradigms – agree that future usage of Ibrance may not be limited to combination with Femara, and that it could well be combined with many other aromatase inhibitors. KOLs also explain that the PALOMA-3 trial would be important in determining the future positioning of Ibrance. Specifically, the KOLs note that using Ibrance in pretreated patients will position it in the same setting as Novartis' Afinitor (everolimus).

"Considering the mechanism of action, I think we may use palbociclib in combination with other endocrine therapies like anastrozole, tamoxifen and fulvestrant. I don't think the specific endocrine therapy it is combined with will be an issue. It is the same for Afinitor - we use it with exemestane, but sometimes we use it with tamoxifen.” - EU Key Opinion Leader

"For the time being, I see palbociclib and everolimus as existing in two different spheres. Now palbociclib is being studied in pretreated patients in PALOMA-3. Eventually we'll see some of that data and that would be a setting that is more competitive with everolimus." - US Key Opinion Leader

A recent Physician Views Poll conducted by FirstWord confirms the KOLs' views of Ibrance, with 44 percent of oncologists saying they would 'very likely' attempt to use Ibrance with an alternative aromatase inhibitor, 25 percent stating they were 'moderately likely' and 9 percent said they were 'extremely likely' to do so. The specialists interviewed for the report are eagerly anticipating results from the PALOMA-2 confirmatory study and are optimistic regarding Ibrance’s success in the HER2-negative/HR-positive breast cancer population.

For companies operating in the EU and US breast cancer market, Breast Cancer: KOL Insight; New CDK inhibitors and PARP inhibitors will transform treatment paradigms, is a must read. The report gives actionable insights and commentary on some of the most critical issues in the breast cancer space, and provides perspectives on how targeted therapy pipeline drugs could fair in a market ripe for change. The report also discusses how treatment paradigms could change in HER2-positive breast cancer, HER2-negative/HR-positive breast cancer and triple-negative breast cancer. For more information, please click here.

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