Palbociclib is Safe for Women with Advanced Breast Cancer Who Have Unique Gene Alteration

Newswise — WASHINGTON (December 9, 2019) — Women who receive palbociclib (Ibrance ®) to treat their advanced breast cancer and have a gene alteration that can lead to a condition known as benign ethnic neutropenia (BEN), can safely receive the drug without major concerns of developing infections associated with neutropenia, or low white blood cell counts, say Georgetown Lombardi Comprehensive Cancer Center researchers. African American women have a higher incidence of BEN than other races and have been underrepresented in trials testing this medicine so palbociclib’s safety in this population wasn’t fully known.

This clinical trial result will be presented in a poster session at the San Antonio Breast Cancer Symposium on December 11, 2019, in San Antonio, Texas.

Many clinical trials require patients to have normal white blood cell counts at enrollment. Specifically, clinical trials of palbociclib have shown that women can develop neutropenia (low neutrophil counts) while taking the drug and therefore be at increased risk of infection. Neutrophils are a type of white blood cell and they are usually one of the first types of white blood cells to reach a site of infection. The lack of infection-fighting white blood cells is often an emergency situation. A BEN diagnosis carries a very low risk of infection, yet women may be given reduced dosages of palbociclib due to lower neutrophil counts even though their infection risk is low.

The phase II PALINA trial, conducted at Georgetown Lombardi and four other centers, used advanced DNA testing at the start of the trial to determine if women had the gene alteration that leads to BEN. The women took palbociclib pills and an estrogen-lowering pill (letrozole) for a maximum of one year. They were then followed to determine if their BEN status affected their safety when taking palbociclib.

“Problematically, African American women and women of African descent have higher rates of death due to breast cancer than white women and their representation in clinical trials has been historically lacking,” said Filipa Lynce, MD, a physician researcher at Georgetown Lombardi Comprehensive Cancer Center who treats patients at MedStar Georgetown University Hospital. “It was important for us to demonstrate that African American and other women with BEN can, and should, receive the same treatment regimen, in this case palbociclib, for their breast cancer as other women.”

The trial enrolled 35 women from Washington, D.C., Baltimore, Chicago and Philadelphia. This current analysis showed that of the 33 women who were tested, 58% had the gene alteration that is associated with lower neutrophil counts. None of the patients in this trial progressed to neutropenia that led to a fever, nor did any of the women discontinue their treatment due to infections. Nearly half of the women did develop a high, but not life-threatening level of neutropenia, resulting in delays in taking their medications.

“We are now more confident that palbociclib can be taken safely by African American and other women with BEN, as long as their white blood cell counts are regularly monitored,” said Lynce. “Our results also point out the need to design trials that enroll women with different ancestries and reflect our patient population so that study outcomes can be applicable to as many women as possible.”

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In addition to Lynce, authors from Georgetown University and its clinical partner MedStar Health, include R. Zhuo, M. Blackburn, C. Gallagher, T. Wu, P. Pohlmann, A. Dilawari, S. Tiwari, A. Chitalia, R. Warren, M. Tan, A. Shajahan-Haq, and C. Isaacs. Additional authors include O. Hahn, University of Chicago, M. Abu-Khalaf, Thomas Jefferson University, Philadelphia, PA, and M. Mohebtash, MedStar Franklin Square Cancer Center, Baltimore, MD.

The authors report the following disclosures relevant to this study: F. Lynce: C; A; AstraZeneca, Jounce, Celgene, BMS, Inivata (unpaid). C; A; BMS, Pfizer, Genentech/Roche, Immunomedics, Calithera, Chugai, Regeneron, Tesaro (Research to the Institution). R. Zhuo: None. M. Blackburn: None. C. Gallagher: None. O. Hahn: None. M. Abu-Khalaf: C; A; Novartis. M. Mohebtash: None. T. Wu: None. P. Pohlmann: C; A; Personalized Cancer Therapy, Sirtex, CARIS Life Sciences. F; A; Dava Oncology, Genentech/Roche, ASCO. C; A; Genentech/Roche, Pfizer, Cascadian Therapeutics. O; A; Immunonet BioSciences. O; A; Intellectual property: Immunological compositions as cancer biomarkers and/or therapeutics. A. Dilawari: None. S. Tiwari: None. A. Chitalia: None. R. Warren: None. M. Tan: None. A. Shajahan-Haq: None. C. Isaacs: C; A; AstraZeneca, Pfizer, Novartis, Genentech and PUMA. F; A; Genentech.

This research was supported by grant from Pfizer, Inc.

Poster P1-19-20: Safety of palbociclib in African American Women with Hormone Receptor Positive HER2 Negative Advanced Breast Cancer and Benign Ethnic Neutropenia: PALINA study

About Georgetown Lombardi Comprehensive Cancer Center Georgetown Lombardi Comprehensive Cancer Center is designated by the National Cancer Institute (NCI) as a comprehensive cancer center. A part of Georgetown University Medical Center, Georgetown Lombardi is the only comprehensive cancer center in the Washington D.C. area. It serves as the research engine for MedStar Health, Georgetown University’s clinical partner. Georgetown Lombardi is also an NCI recognized consortium with John Theurer Cancer Center/Hackensack Meridian Health in Bergen County, New Jersey. The consortium reflects an integrated cancer research enterprise with scientists and physician-researchers from both locations. Georgetown Lombardi seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic, translational and clinical research, patient care, community education and outreach to service communities throughout the Washington region, while its consortium member John Theurer Cancer Center/Hackensack Meridian Health serves communities in northern New Jersey. Georgetown Lombardi is a member of the NCI Community Oncology Research Program (UG1CA239758). Georgetown Lombardi is supported in part by a National Cancer Institute Cancer Center Support Grant (P30CA051008). Connect with Georgetown Lombardi on Facebook (Facebook.com/GeorgetownLombardi) and Twitter (@LombardiCancer).

About Georgetown University Medical Center
Georgetown University Medical Center (GUMC) is an internationally recognized academic health and science center with a four-part mission of research, teaching, service and patient care (through MedStar Health). GUMC’s mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis -- or “care of the whole person.” The Medical Center includes the School of Medicine and the School of Nursing & Health Studies, both nationally ranked; Georgetown Lombardi Comprehensive Cancer Center, designated as a comprehensive cancer center by the National Cancer Institute; and the Biomedical Graduate Research Organization, which accounts for the majority of externally funded research at GUMC including a Clinical and Translational Science Award from the National Institutes of Health.  Connect with GUMC on Facebook (Facebook.com/GUMCUpdate), Twitter (@gumedcenter).