Background: Homologous recombination deficiency (HRD) is a phenotype that is characterized by the inability of a cell to effectively repair DNA double-strand breaks using the homologous recombination repair (HRR) pathway. Loss-of-function genes involved in this pathway can sensitize tumors to poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapy, which target the destruction of cancer cells by working in concert with HRD through synthetic lethality. However, to identify patients with these tumors, it is vital to understand how to best measure homologous repair (HR) status and to characterize the level of alignment in these measurements across different diagnostic platforms. A key current challenge is that there is no standardized method to define, measure, and report HR status using diagnostics in the clinical setting.Methods: Friends of Cancer Research convened a consortium of project partners from key healthcare sectors to address concerns about the lack of consistency in the way HRD is defined and methods for measuring HR status.Results: This publication provides findings from the group’s discussions that identified opportunities to align the definition of HRD and the parameters that contribute to the determination of HR status. The consortium proposed recommendations and best practices to benefit the broader cancer community.Conclusion: Overall, this publication provides additional perspectives for scientist, physician, laboratory, and patient communities to contextualize the definition of HRD and various platforms that are used to measure HRD in tumors.

Purpose: Circulating tumor DNA (ctDNA) holds promise as an early endpoint to predict overall survival (OS). The creation and structured interrogation of aggregated datasets inform the hypothesis that ctDNA is reasonably likely to predict treatment benefit. Friends of Cancer Research convened a diverse working group to establish and implement an analysis plan assessing patient-level associations between changes in ctDNA levels with OS and progression-free survival (PFS). Experimental Design: The aggregate dataset included eight clinical trials representing 940 patients with biomarker-positive advanced non–small cell lung cancer treated with tyrosine kinase inhibitors. Detection of baseline and on-treatment ctDNA was assessed for associations with OS and PFS. Additionally, combinations of ctDNA detection and RECIST measurements up to 10 weeks on treatment were considered. Results: Patients with detected ctDNA at baseline that became nondetected on treatment (“clearance”) experienced improved OS compared with patients with persistently detected ctDNA (adjusted HR = 2.12, P < 0.001). This pattern was also seen in the subset of patients with stable disease as measured by RECIST within 10 weeks of treatment initiation (adjusted HR = 4.15, P < 0.001). Results were similar for PFS. Conclusions: In patients with oncogene-driven advanced non–small cell lung cancer treated with tyrosine kinase inhibitors, ctDNA clearance within 10 weeks of treatment initiation was associated with improved OS and PFS. These patient-level results support the growing evidence that demonstrates a change in ctDNA levels during treatment is associated with clinical benefit. Future prospective trials should include predefined thresholds of molecular response to advance the utility of ctDNA as an early endpoint.

In nontransformed bovine mammary epithelial cells, the intrinsic apoptosis inducer anisomycin (ANS) induces IGFBP-3 expression and nuclear localization and knockdown of IGFBP-3 attenuates ANS-induced apoptosis. Others have shown in prostate cancer cells that exogenous IGFBP-3 induces apoptosis by facilitating nuclear export of the orphan nuclear receptor Nur77 and its binding partner, retinoid X receptor-α (RXRα). The goal of the present work was to determine whether endogenous IGFBP-3 plays a role in ANS-induced apoptosis by facilitating nuclear transport of Nur77 and/or RXRα in nontransformed cells. Knockdown of Nur77 with siRNA decreased ANS-induced cleavage of caspase-3 and -7 and their downstream target, PARP, indicating a role for Nur77 in ANS-induced apoptosis. In cells transfected with IGFBP-3, IGFBP-3 associated with RXRα but not Nur77 under basal conditions, however, IGFBP-3 co-precipitated with phosphorylated forms of both proteins in ANS-treated cells. Indirect immunofluorescence and cell fractionation techniques showed that ANS induced phosphorylation and transport of Nur77 from the nucleus to the cytoplasm and these effects were attenuated by knockdown of IGFBP-3. These data suggest that endogenous IGFBP-3 plays a role in intrinsic apoptosis by facilitating phosphorylation and nuclear export of Nur77 to the cytoplasm where it exerts its apoptotic effect. Whether this mechanism involves a physical association between endogenous IGFBP-3 and Nur77 or RXRα remains to be determined.

The FDA's Oncology Center of Excellence's (OCE) launch of Project Optimus signals increased focus on dose optimization approaches in oncology drug development, particularly toward optimization in the premarket setting. Although sponsors continue to adapt premarket study designs and approaches to align with FDA's expectations for dose optimization, including consideration of the optimal dosage(s), there are still instances where questions remain at the time of approval about whether the approved doses or schedules are optimal. In these cases, FDA can exercise regulatory flexibility by issuing postmarketing requirements (PMR) and avoid delaying patient access to promising therapies. This landscape analysis demonstrates that over the past decade (2012–2022), FDA frequently used PMRs to answer additional questions about dosing for novel oncology approvals. We found more than half of drugs (78/132, 59.1%) had a dosing PMR and observed a recent increase in PMRs intended to evaluate whether a lower dose could be more optimal. These results suggest there are opportunities to adapt premarket dose optimization strategies and leverage innovative development tools to ensure timely identification of the optimal dose.

PURPOSE: Real-world data (RWD) holds promise for ascribing a real-world (rw) outcome to a drug intervention; however, ascertaining rw-response to treatment from RWD can be challenging. Friends of Cancer Research formed a collaboration to assess available data attributes related to rw-response across RWD sources to inform methods for capturing, defining, and evaluating rw-response. MATERIALS AND METHODS: This retrospective noninterventional (observational) study included seven electronic health record data companies (data providers) providing summary-level deidentified data from 200 patients diagnosed with metastatic non–small cell lung cancer (mNSCLC) and treated with first-line platinum doublet chemotherapy following a common protocol. Data providers reviewed the availability and frequency of data components to assess rw-response (ie, images, radiology imaging reports, and clinician response assessments). A common protocol was used to assess and report rw-response end points, including rw-response rate (rwRR), rw-duration of response (rwDOR), and the association of rw-response with rw-overall survival (rwOS), rw-time to treatment discontinuation (rwTTD), and rw-time to next treatment (rwTTNT). RESULTS: The availability and timing of clinician assessments was relatively consistent across data sets in contrast to images and image reports. Real-world response was analyzed using clinician response assessments (median proportion of patients evaluable, 77.5%), which had the highest consistency in the timing of assessments. Relative consistency was observed across data sets for rwRR (median 46.5%), as well as the median and directionality of rwOS, rwTTD, and rwTTNT. There was variability in rwDOR across data sets. CONCLUSION: This collaborative effort demonstrated the feasibility of aligning disparate data sources to evaluate rw-response end points using clinician-documented responses in patients with mNSCLC. Heterogeneity exists in the availability of data components to assess response and related rw-end points, and further work is needed to inform drug effectiveness evaluation within RWD sources.

Background Resistance to endocrine therapy in estrogen receptor–positive (ER+) breast cancer remains a significant clinical problem. Riluzole is FDA-approved for the treatment of amyotrophic lateral sclerosis. A benzothiazole-based glutamate release inhibitor with several context-dependent mechanism(s) of action, riluzole has shown antitumor activity in multiple malignancies, including melanoma, glioblastoma, and breast cancer. We previously reported that the acquisition of tamoxifen resistance in a cellular model of invasive lobular breast cancer is accompanied by the upregulation of GRM mRNA expression and growth inhibition by riluzole. Methods We tested the ability of riluzole to reduce cell growth, alone and in combination with endocrine therapy, in a diverse set of ER+ invasive ductal and lobular breast cancer–derived cell lines, primary breast tumor explant cultures, and the estrogen-independent, ESR1-mutated invasive lobular breast cancer patient-derived xenograft model HCI-013EI. Results Single-agent riluzole suppressed the growth of ER+ invasive ductal and lobular breast cancer cell lines in vitro, inducing a histologic subtype-associated cell cycle arrest (G0-G1 for ductal, G2-M for lobular). Riluzole induced apoptosis and ferroptosis and reduced phosphorylation of multiple prosurvival signaling molecules, including Akt/mTOR, CREB, and Fak/Src family kinases. Riluzole, in combination with either fulvestrant or 4-hydroxytamoxifen, additively suppressed ER+ breast cancer cell growth in vitro. Single-agent riluzole significantly inhibited HCI-013EI patient-derived xenograft growth in vivo, and the combination of riluzole plus fulvestrant significantly reduced proliferation in ex vivo primary breast tumor explant cultures. Conclusion Riluzole may offer therapeutic benefits in diverse ER+ breast cancers, including lobular breast cancer.