PFE's Atirmociclib 2L Breast Cancer Study Hits Goal, Aid Pipeline Push

Pfizer PFE is one of the leading oncology drugmakers with a strong presence across breast, genitourinary, thoracic, gastrointestinal and blood cancers. The company has a well-established portfolio of approved cancer therapies and a robust pipeline, focusing on diverse modalities such as small molecules, antibody-drug conjugates (ADCs) and immuno-oncology biologics.

Pfizer’s revenues from the oncology portfolio grew 8% year over year in 2025, driven by drugs like Xtandi, Lorbrena, the Braftovi-Mektovi combination and Padcev. Oncology sales comprised around 27% of the company’s total revenues in 2025.

Besides working on expanding the labels of approved cancer drugs, Pfizer is also focusing on advancing its oncology pipeline with several candidates in mid-to-late-stage development.

Key oncology candidates in late-stage development include atirmociclib (a CDK4 inhibitor for metastatic breast cancer) and sigvotatug vedotin (an ADC for metastatic non-small cell lung cancer or NSCLC). Meanwhile, a regulatory application seeking approval for vepdegestrant, a small-molecule PROTAC for ER+/HER2- metastatic breast cancer, is under review in the United States, while that for sasanlimab in BCG-naive high-risk non-muscle invasive bladder cancer is under review in the EU, and can be launched next year.

Reflecting the growing optimism around its oncology pipeline push, Pfizer reported positive top-line data from the phase II FOURLIGHT-1 study evaluating atirmociclib in second-line metastatic breast cancer.

The FOURLIGHT-1 study, which evaluated atirmociclib in combination with fulvestrant, versus fulvestrant or everolimus plus exemestane for treating patients with HR-positive, HER2-negative advanced or metastatic breast cancer who had received prior CDK 4/6 inhibitor-based therapy, met its primary endpoint.

Data from the same showed that treatment with atirmociclib regime led to a statistically significant and clinically meaningful improvement in progression-free survival (PFS) as assessed by the investigator. Treatment with atirmociclib led to a 40% reduction in the risk of disease progression or death. Overall survival, which was a secondary endpoint of the FOURLIGHT-1 study, was not mature at the time of the analysis.

Treatment with atirmociclib demonstrated a manageable safety profile and was well tolerated.

Management noted that the results from the FOURLIGHT-1 study are particularly encouraging since it included patients whose disease progressed shortly after prior CDK4/6 inhibitor therapy, a hard-to-treat patient population. More than 90% of patients began treatment with atirmociclib within three months of their last CDK4/6 inhibitor therapy.

Pfizer is also evaluating atirmociclib in a phase III registrational study for treating first-line HR+/HER2- metastatic breast cancer. Also, data from a phase II neoadjuvant study evaluating atirmociclib in early breast cancer will be shared at a future medical conference.

If successfully developed and upon potential approval, management believes atirmociclib could meaningfully distinguish itself from the CDK4/6 inhibitor class, the current standard-of-care backbone in HR-positive breast cancer. This also underscores PFE’s goal of having eight or more blockbuster oncology medicines in its portfolio by 2030.

Competition in the Oncology Space

Pfizer is one of the largest developers of cancer medicines. Other large players in the oncology space are AstraZeneca AZN, Merck MRK, J&J JNJ and Bristol-Myers.

For AstraZeneca, oncology sales now comprise around 44% of total revenues. Sales in its oncology segment rose 14% at constant exchange rate (CER) in 2025. AstraZeneca’s strong oncology performance was driven by medicines such as Tagrisso, Lynparza, Imfinzi, Calquence and Enhertu (in partnership with Daiichi Sankyo).

Merck’s key oncology medicines are PD-L1 inhibitor, Keytruda and PARP inhibitor, Lynparza, which it markets in partnership with AstraZeneca. Keytruda, approved for several types of cancer, alone accounts for more than 50% of Merck’s pharmaceutical sales. Keytruda recorded sales of $31.7 billion in 2025, up 7% year over year.

J&J’s oncology sales now comprise around 27% of its total revenues. Its oncology sales rose 20.9% on an operational basis in 2025 to $25.4 billion. While J&J’s older cancer drugs, multiple myeloma treatment Darzalex and prostate cancer drug Erleada, are key contributors to its top-line growth, new drugs such as Carvykti, Tecvayli, Talvey and Rybrevant, plus Lazcluze, hold the key to long-term growth.

Bristol-Myers’ key cancer drug is PD-L1 inhibitor, Opdivo, which accounts for around 21% of its total revenues. Opdivo’s sales rose 8% to $10 billion in 2025.

PFE's Price Performance, Valuation and Estimates

Year to date, shares of Pfizer have rallied 10.2% against the industry’s decline of 0.1%.

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From a valuation standpoint, Pfizer appears attractive relative to the industry and is trading below its five-year mean. Going by the price/earnings ratio, Pfizer’s shares currently trade at 9.33 forward earnings, substantially lower than 17.65 for the industry as well as the stock’s five-year mean of 10.15.

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The Zacks Consensus Estimate for 2026 earnings has declined from $2.99 per share to $2.97, while that for 2027 has declined from $2.83 per share to $2.82 over the past 60 days.

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PFE Zacks Rank

Pfizer has a Zacks Rank #3 (Hold) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

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