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Talazoparib Significantly Extends Progression-Free Survival in Phase 3 EMBRACA Trial of Patients with Metastatic Breast Cancer

December 8, 2017 -- Pfizer Inc. (NYSE:PFE) today announced that the Phase 3 EMBRACA trial in patients with germline (inherited) BRCA1/2-positive (gBRCA+) locally advanced and/or metastatic breast cancer (MBC) demonstrated superior progression-free survival (PFS) in patients treated with talazoparib, compared to patients who received physician’s choice standard of care chemotherapy. Median PFS was 8.6 months (95% CI: 7.2, 9.3) for patients treated with talazoparib and 5.6 months (95% CI: 4.2, 6.7) for those treated with chemotherapy [HR: 0.54 (95% CI: 0.41, 0.71), p<0.0001]. This represents a 46% reduction in the risk of disease progression. In addition, the proportion of patients achieving a complete or partial response (objective response rate) in the talazoparib group was more than twice that of the control arm (62.6% for talazoparib vs. 27.2% for chemotherapy [OR: 4.99 (95% CI: 2.9-8.8), p<0.0001]). Talazoparib is an investigational, oral, dual-mechanism poly ADP ribose polymerase (PARP) inhibitor that is taken once daily. The data will be presented today as an oral presentation at the 2017 San Antonio Breast Cancer Symposium.

“Patients with germline BRCA-positive breast cancer are typically diagnosed at a younger age than those with nonhereditary breast cancer, and there are no therapies specifically approved for them outside of current standard of care therapies,” said Jennifer Litton, MD, lead investigator and associate professor in the breast medical oncology department of The University of Texas MD Anderson Cancer Center. “EMBRACA supports the potential of talazoparib to give these patients additional time without disease progression, compared to chemotherapy.”

Pfizer will be discussing these data from EMBRACA, the largest Phase 3 trial performed to date of a PARP inhibitor in patients with gBRCA+ MBC, with worldwide health authorities. There are currently limited treatment options for patients with this molecular subtype.

“Results from the EMBRACA study are very encouraging and a great example of precision drug development. By enrolling only patients with germline BRCA-positive metastatic breast cancer, treatment with talazoparib reduced the risk of disease worsening by nearly half, compared with current standard of care chemotherapy. This includes heavily pretreated patients, those with hormone receptor-positive disease and those who had a history of brain metastases,” said Mace Rothenberg, MD, chief development officer, Oncology, Pfizer Global Product Development.

The results of the EMBRACA trial also showed that the PFS benefit with talazoparib was consistent across prespecified subgroups, including hormone receptor (HR) status (triple negative [TNBC] or hormone receptor-positive [HR+]), BRCA mutation (1 or 2), prior chemotherapy (whether patients had none or up to three chemotherapies before talazoparib), and history of central nervous system (CNS) metastases. There also was a statistically significant delay in the time to clinically meaningful deterioration in global health status/quality of life with talazoparib versus chemotherapy (HR 0.38 [95% CI 0.26-0.55], p<0.0001), as measured by the EORTC QLQ-C30, a cancer-specific, patient-reported quality of life questionnaire.

Adverse events (AEs) observed with talazoparib were consistent with findings from previous trials. The most common AEs observed with talazoparib (any grade in at least 15% of patients) were anemia (52.8%), fatigue (50.3%), nausea (48.6%), neutropenia (34.6%), headache (32.5%), thrombocytopenia (26.9%), alopecia (25.2%), vomiting (24.8%), diarrhea (22%), constipation (22%), decreased appetite (21.3%), back pain (21%) and dyspnea (17.5%). The incidence of serious AEs was 31.8% in the talazoparib arm and 29.4% in the chemotherapy arm. Discontinuations due to AEs occurred in 7.7% of patients in the talazoparib arm and 9.5% of patients in the chemotherapy arm.

In addition to EMBRACA, talazoparib demonstrated promising activity in patients with gBRCA+ MBC in the Phase 2 ABRAZO trial. Patients in ABRAZO had either been previously treated with platinum-based chemotherapy or were heavily pretreated with at least three prior lines of non-platinum-based chemotherapy.1

About EMBRACA

EMBRACA is a global Phase 3, open-label, randomized, parallel, 2-arm trial of talazoparib versus protocol-specific physician’s choice of standard single-agent chemotherapy (PCT [capecitabine, eribulin, gemcitabine or vinorelbine]) in gBRCA+ patients who may have received up to three prior cytotoxic chemotherapy regimens for locally advanced and/or metastatic breast cancer. Patients enrolled had a diagnosis of TNBC or HR+/HER2-negative breast cancer. The trial randomized (2:1) 431 patients to receive talazoparib (1.0 mg) once daily or PCT.

About Germline BRCA1/2-Positive Breast Cancer

BRCA1 and BRCA2 are human genes that produce proteins involved in DNA repair. When either of these genes is altered or mutated, DNA repair may not progress correctly. This can lead to the development of certain types of cancer such as breast cancer.2,3,4 BRCA mutations can be hereditary (germline) or occur spontaneously (sporadic).2 Together, BRCA1 and BRCA2 mutations account for about 20 to 25 percent of hereditary breast cancers and about 5 to 10 percent of all breast cancers.5,6 Up to 65 percent of women who inherit a BRCA mutation will develop breast cancer by age 70.2 Epidemiologic studies indicate that individuals with gBRCA+ status are diagnosed with breast cancer at a median age of 40-45, which is approximately 20 years younger than the overall breast cancer population.7

About Talazoparib

Talazoparib is an investigational anti-cancer compound called a PARP (poly ADP ribose polymerase) inhibitor. Preclinical studies suggest that talazoparib is highly potent and has a dual mechanism of action, with the potential to induce tumor cell death by blocking PARP enzyme activity and trapping PARP on the sites of DNA damage. Talazoparib is currently being evaluated in advanced gBRCA+ breast cancer as well as other cancer types with deficiencies in DNA damage repair (DDR). It is also being studied in DDR-deficient prostate cancer and in combination with immunotherapy in various tumor types. Talazoparib has not been approved by any regulatory authorities for the treatment of any disease.

About Pfizer Oncology

Pfizer Oncology is committed to pursuing innovative treatments that have a meaningful impact on people living with cancer. Our growing pipeline of biologics, small molecules, and immunotherapies is focused on identifying and translating the best scientific breakthroughs into clinical application for patients across a diverse array of solid tumors and hematologic cancers. Today, we have 10 approved oncology medicines and 17 assets currently in clinical development. By maximizing our internal scientific resources and collaborating with other companies, government and academic institutions, as well as non-profit and professional organizations, we are bringing together the brightest and most enterprising minds to take on the toughest cancers. Together we can accelerate breakthrough treatments to patients around the world and work to redefine life with cancer.

Working together for a healthier world®

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products. Our global portfolio includes medicines and vaccines as well as many of the world's best-known consumer health care products. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 150 years, we have worked to make a difference for all who rely on us. We routinely post information that may be important to investors on our website at www.pfizer.com. In addition, to learn more, please visit us on www.pfizer.com and follow us on Twitter at @Pfizer and @Pfizer_News, LinkedIn, YouTube, and like us on Facebook at Facebook.com/Pfizer.

DISCLOSURE NOTICE: The information contained in this release is as of December 8, 2017. Pfizer assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.

This release contains forward-looking information about a product candidate, talazoparib, and Pfizer’s oncology portfolio, including their potential benefits and regulatory submission plans, that involves substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Risks and uncertainties include, among other things, the uncertainties inherent in research and development, including, without limitation, the ability to meet anticipated clinical trial commencement and completion dates and regulatory submission dates, as well as the possibility of unfavorable clinical trial results, including unfavorable new clinical data and additional analyses of existing clinical data; the risk that clinical trial data are subject to differing interpretations, and, even when we view data as sufficient to support the safety and/or effectiveness of a product candidate, regulatory authorities may not share our views and may require additional data or may deny approval altogether; whether regulatory authorities will be satisfied with the design of and results from our clinical studies; whether and when new drug applications may be filed in any jurisdictions for talazoparib or any other oncology products; whether and when such applications may be approved by regulatory authorities, which will depend on the assessment by such regulatory authorities of the benefit-risk profile suggested by the totality of the efficacy and safety information submitted, and, if approved, whether talazoparib or any such other oncology products will be commercially successful; decisions by regulatory authorities regarding labeling and other matters that could affect the availability or commercial potential of talazoparib or other oncology products; and competitive developments.

A further description of risks and uncertainties can be found in Pfizer’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned “Risk Factors” and “Forward-Looking Information and Factors That May Affect Future Results”, as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

1 Turner et al. Final results of a phase 2 study of talazoparib (TALA) following platinum or multiple cytotoxic regimens in advanced breast cancer patients (pts) with germline BRCA1/2 mutations (ABRAZO). ASCO 2017. http://ascopubs.org/doi/abs/10.1200/JCO.2017.35.15_suppl.1007.
2 National Cancer Institute. BRCA1 and BRCA2: Cancer risk and genetic testing. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact.... Accessed November 28, 2017.
3 Evers et al. A high throughput pharmaceutical screen identifies compounds with specific toxicity against BRCA2-deficient tumors. Clin Cancer Res. 2010 Jan 1; 16(1): 99–108.
4 Livraghi L, Garber J. PARP inhibitors in the management of breast cancer: Current data and future prospects. BMC Medicine. 2015;13:188.
5 Easton DF. How many more breast cancer predisposition genes are there? Breast Cancer Research. 1999; 1(1):14–17.
6 Campeau PM, Foulkes WD, Tischkowitz MD. Hereditary breast cancer: New genetic developments, new therapeutic avenues. Human Genetics. 2008; 124(1):31–42.
7 Kim et al. Incidence of Germline BRCA1- and BRCA2-Mutated Breast Cancer in the United States. San Antonio Breast Cancer Symposium. 2016.

Source: Pfizer Inc.

Posted: December 2017

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