Expanding the use of PARP inhibitors
Davidson, a medical oncologist and Fred Hutch's Executive Vice President for Clinical Affairs, received another year of funding to research the expanded use of the targeted treatment known as PARP inhibitors. Currently, this type of therapy is highly effective in about 60% of BRCA mutation-driven breast cancers.
PARP inhibitors could potentially help other patients, though, if they can be identified.
The BCRF funding will be used to launch a clinical trial of a novel molecular imaging radiotracer known as fluorthanatrace, or (18F) FTT PET, a PARP-targeted tracer, to measure PARP1 tumor expression without the need for biopsy. Led by medical oncologist Shaveta Vinayak, MD, and Director of Molecular Imaging Delphine Chen, MD, the trial is scheduled to start recruiting in early 2024.
The FTT PET will evaluate patients’ tumor heterogeneity as well as the extent of its PARP1 expression; the researchers hope this will help determine whether it can predict PARP inhibitor response in germline BRCA or other DNA repair mutation-associated metastatic breast cancer.
“With targeted therapies such as PARP inhibitors, giving the ‘right treatment’ to the ‘right patient’ at the ‘right time’ can significantly impact cancer control and patient survival,” Davidson wrote in her proposal. “This will allow us to validate the utility of a non-invasive imaging tool to predict PARP inhibitor therapy response.”
Building better recurrence prediction models
Li, holder of the Helen G. Edson Endowed Chair for Breast Cancer Research, received another year’s worth of funding — $225,000 — to continue his work to uncover predictors of cancer recurrence within different types of breast cancer.
Previous work by Li and Fred Hutch computational biologist Gavin Ha, PhD, focused on the development and validation of a risk prediction model for luminal B breast cancer recurrence using integrated genomic, transcriptomic and clinical/epidemiologic data.
Luminal B breast cancers tend to have a poorer prognosis than luminal A breast cancers (those that are positive for estrogen and progesterone and negative for HER2 expression), which grow more slowly.
This new funding will be used to create better recurrence prediction for each of the most common breast cancer subtypes, including both basal-like (often referred to as triple negative) and luminal A using spatial transcriptomic analyses.
“Several studies underscore the biological importance and prognostic and predictive value of detailed spatially resolved single-cell phenotyping of immune cells,” Li wrote in his proposal.
Li and team will use patient data and samples from a large, population-based cohort known as BRAVO (Breast Cancer Risk Factors And Various Outcomes), which contains 1,216 luminal A, 607 luminal B, 487 HER2-overexpressing and 1,267 triple-negative breast cancer patients.
In particular, they will focus on matched sets of breast cancer patients who did versus did not experience a recurrence of their cancer. They plan to conduct spatial transcriptomic analyses on all these patients (approximately 280 women) to identify and spatially map the many different cell types and states at single-cell resolution.
Aims for this phase of the study are twofold. First, they plan to perform deep immune cellular profiling of tumor tissue biospecimens from the matched sets of breast cancer patients at single-cell resolution in hopes of discovering new spatially resolved biomarkers of recurrence for basal-like, luminal B and luminal A breast cancers.
Second, they plan to develop and validate multi-omic predictors of cancer recurrence of each subtype using machine learning.
“We aim to identify patients who will rapidly fail standard first-line therapy,” Li wrote. “Currently, there are no recurrence risk prediction models specific for luminal B or basal-like breast cancer patients that have sufficient performance to be clinically useful.”
The bottom line?
“We hope to improve the delivery of tailored treatments for patients at a high risk of recurrence while at the same time being able to identify low risk patients who may be able to avoid more toxic/invasive breast cancer treatments,” Li said.
Why does exercise improve breast cancer outcomes?
McTiernan’s ACE exercise study received an additional $225,000 to fund another year of her investigation into the mechanisms of how physical exercise improves breast cancer outcomes.
Previously, the ACute Effects of Exercise in Women (ACE) randomized controlled trial examined changes in biomarkers related to inflammation and blood vessel growth in blood and muscle tissue samples from 102 women without breast cancer before and after 45 minutes of either exercise or rest (the control arm).
After analysis, McTiernan and team found intriguing evidence that exercise changes muscle cell proteins involved in the regulation of genes that are important in breast cancer.
The next phase — in collaboration with Fred Hutch co-investigators Catherine Duggan, PhD, Ching-Yun Wang, PhD, Jean de Dieu Tapsoba, PhD and Taran Gujral, PhD — will continue to test the effects of acute exercise on muscle, fat and blood biomarkers in women with breast cancer.
Last year, McTiernan began enrolling for a second phase of ACE, open to women ages 36 to 75 who’ve been diagnosed with stage 0 to stage 3 breast cancer within the last five years and who have finished all treatment at least six months ago (anti-hormone treatments are okay).
Funds from BCRF will be used to continue the study’s implementation.
McTiernan and colleagues will measure the effect of acute exercise on the levels of proteins in participants’ blood, in samples of fat from the abdomen, and in muscle tissue, and will examine how the proteins are activated in response to exercise. Protein levels will be measured in Gujral’s lab, which has created technologies capable of analyzing different signaling networks in cell lines and human tissue samples.
The researchers will also compare tissue samples before and after exercise to see how exercise effects differ in women with and without breast cancer.
“This trial will provide answers to questions on how exercise affects biology related to breast cancer, so that precise prescriptions can be provided to women to change lifestyle to reduce their risk and improve prognosis,” McTiernan said.