Citations

Abstract Introduction: Epoxy fatty acid (EpFA) mechanisms of hormone therapy resistance (HTR) in ER+HER2- breast cancer (BC) are poorly understood. EETs are EpFAs that contribute to BC progression and HTR by promoting oxidative phosphorylation (OXPHOS). However, it remains unclear how EETs contribute to HTR. In this study, two fulvestrant resistant (FR) subclones of the letrozole resistant (LR) MCF-7AC1 line were isolated (termed LR/FR) and were incidentally resistant to the CDKi palbociclib (PR) (termed MCF-7AC1 LR/FR/PR or multiply resistant - MCF-7AC1 MR). These HTR cell lines exhibited CYP3A4 upregulation (2.3- to 4.3-fold) and increased cellular (±)14,15-EET levels, which were suppressed by biguanide treatment (P<0.05). Structure activity studies led to the design of hexyl cuban-1-yl biguanide (HCB) and fluorinated HCB derivatives C5F2-HCB and C6F3-HCB, which inhibited CYP3A4-mediated EET biosynthesis and growth of the HTR lines. HCB fluorination improved pharmacokinetics (PK) and toxicity. Methods: HCB and fluorinated HCBs were tested for impact on EET biosynthesis, OXPHOS, PK, and growth inhibition and reversal of hypoxia in the MCF-7AC1 MR tumor model. Results: Fulvestrant selection for MCF-7AC1 MR cell lines resulted in undetectable cyclin D1 and estrogen receptor (ERα) expression, while cyclin E1, CDK4, CDK6, CYP3A4, and c-MYC were upregulated (P<0.001). MCF-7 MR cells demonstrated 1.8, 1.4, and 1.2- fold higher levels of (±)8,9, (±)11,12, and (±)14,15-EET compared to parental MCF-7 cells (P<0.05). The most potent fluorinated HCB, C6F3-HCB, suppressed cellular levels of (±)8,9-EET, (±)11,12-EET, and (±)14,15-EET by 53-60% (P<0.029). The MCF-7AC1 MR cells were more potently inhibited by HCBs and fluorinated derivatives compared to the MCF-7 cell line. Comparing an MCF-7 MR line vs. MCF-7, HCB exhibited IC50 values of 4.1 vs. 7.0 uM, C5F2-HCB 10 vs. 25 uM, and C6F3-HCB 5.4 vs. 12 uM (P values all <0.05). C5F2-HCB exhibited the best PK and treatment of the MCF-7AC1 MR xenograft model showed reversal of hypoxia (P<0.05) and transient inhibition by C5F2-HCB (P=0.025 at 20 days). P/F also transiently inhibited this model (P=0.006 at 20 days). C5F2-HCB and P/F showed synergy in vitro (CI=0.46) leading to testing of C5F2-HCB/P/F in vivo enabled by acceptable toxicity of the triplet in mice. This combination showed synergy in vivo vs. standard of care palbociclib/fulvestrant by nonparametric statistical tests (Mann Whitney; P=0.0389; Kolmogorov-Smirnov; P=0.0473), providing a pathway for possible clinical development of the combination. Conclusions: MR BC cell lines exhibit upregulation of CYP3A4 and biosynthesis of EETs, indicating a role for EETs in HTR. The C5F2-HCB/P/F exhibits activity against the highly resistant MCF-7 MR xenograft with acceptable toxicity indicating an avenue for clinical development. Citation Format: Zhijun Guo, Jianxun Lei, Christian T. Wells, Allison M. Makovec, Andrew C. Yates, Swaathi Jayaraman, John R. Hawse, Joshua A. McCarra, Qing Cao, Michael J. Pryzbilla, Brenda L. Koniar, Beverly J. Norris, Craig M. Florey, Robert J. Schumacher, Michael A. Farrar, Kaylee L. Schwertfeger, Elizabeth A. Ambrose, Henry Wong, Gunda I. Georg, Antonino D'Assoro, Matthew P. Goetz, David A. Potter. Fluorinated cuban-1-yl biguanides overcome hormone therapy resistance to standard of care fulvestrant, and palbociclib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB196.

Abstract Despite long-standing interest in combining topoisomerase I (TOP1) poisons with PARP inhibitors (PARPis), the mechanistic basis for the variable and often unpredictable response to this strategy remains unclear. Early preclinical studies suggested that PARP inhibition amplifies TOP1 poison-induced DNA damage, implying broad therapeutic potential; however, emerging translational and clinical data—particularly in ovarian cancer—indicate that synergy is context-dependent and governed by tumor-intrinsic features that have not been fully defined.Here we assessed determinants of response in five HR proficient ovarian cancer (OC) patient-derived xenografts (PDXs) previously treated with the SN-38 prodrug etirinotecan pegol (NKTR-102) in combination with the PARPi rucaparib (C. Nitschmann, Clin. Cancer Res. 22(2) Suppl. B50, 2016). Although all models were refractory to single-agent rucaparib, 50% exhibited enhancement of NKTR-102-induced tumor regression with the addition of rucaparib. Neither PARP1 abundance nor extent of rucaparib-mediated poly(ADP-ribose) suppression correlated with therapeutic benefit. Instead, sensitization was restricted to PDXs intrinsically responsive to NKTR-102 and was strongly associated with high levels of NKTR-102-induced TOP1-DNA covalent complexes. In further analysis, 2 of 3 resistant PDXs exhibited high levels of the ABC transporter ABCG2 despite lack of previous therapy, revealing a previously underappreciated mechanism of de novo resistance that limits effective TOP1 inhibitor activity independent of homologous recombination status. Notably, NKTR-102 response did not track with platinum/taxane sensitivity, highlighting the distinct molecular circuitry governing TOP1 poison susceptibility.Collectively, these findings demonstrate that rucaparib can potentiate NKTR-102-induced regression in tumors capable of forming abundant TOP1-DNA covalent complexes. This work identifies TOP1-DNA complex trapping and lack of ABCG2 expression as mechanistic predictors of benefit, providing an updated framework for selecting patients most likely to respond to TOP1 poison/PARPi combinations and challenging the long-standing assumption that PARP inhibition can universally resensitize tumors to TOP1 poisons. Citation Format: Annapoorna Venkatachalam, Caroline C. Nitschmann, Karen S. Flatten, Rachel Hurley, Xiaonan Hou, Cristina Correia, Paula A. Schenider, Krista Goergen, Matthew Maurer, Ethan P. Heinzen, Ann L. Oberg, S John Weroha, Paul Haluska, Scott H. Kaufmann, Elizabeth M. Swisher. TOP1-DNA protein complex as a predictive biomarker for NKTR-102/Rucaparib combination therapy in PARP-inhibitor resistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB364.

Abstract Background: Despite efficacy in metastatic clear cell renal cell carcinoma (ccRCC), immunotherapy currently has no role in the neoadjuvant setting. Suppressive tumor-associated macrophages (TAMs) are known to mediate resistance to immune checkpoint blockade (ICB) in ccRCC. In preclinical studies, IL-1β blockade reprograms TAMs toward an anti-tumor phenotype and promotes T cell activation, creating a tumor microenvironment (TME) more sensitive to ICB. To test this in patients, we conducted a correlative-rich neoadjuvant trial of IL-1β + PD-1 inhibition in localized ccRCC. Methods: SPARC-1 is a single-center, phase 1b study assessing the safety and feasibility of neoadjuvant canakinumab (αIL-1β) and spartalizumab (αPD-1) in patients with localized ccRCC (T1b-T4NanyM0 or TanyN1M0). All patients received 2 doses of canakinumab (300mg IV, Q4w) and spartalizumab (400mg IV, Q4w), 6 weeks (±7 days) prior to nephrectomy. The primary endpoint was safety and feasibility. Key secondary and exploratory endpoints included 12-month metastasis-free survival rate, pathologic response rate, and quantification of immune cell infiltration. To characterize immunologic reprogramming, fresh tumor specimens were collected at nephrectomy for single-cell RNA sequencing (scRNAseq) and multiparametric flow cytometry. Tissue from a treatment naïve cohort was collected for comparative analysis (n=16). Results: From August 15th, 2018, to January 30th, 2025, 14 patients were enrolled. There were no severe treatment-related adverse events (Grade ≥ 3) attributed to canakinumab or spartalizumab. At a median follow-up of 12.0 months (range, 6.3-12.0 months), the 12-month metastasis-free survival was 100%. Based on the ASSURE nomogram, the mean predicted 12-month recurrence risk was 16.7% (range, 4.7-46.5%). ScRNAseq revealed that treatment with αIL-1β + αPD-1 increased the frequency of TREM2+APOE+ TAMs (p=0.035), a population typically associated with immune suppression. However, these TAMs exhibited a phenotypic shift toward a less immunosuppressive state, with reduced IL-1β expression and increased CXCL9:SPP1 ratio, consistent with anti-tumor TAM polarization. Immune profiling revealed an increased CD8/CD4 T cell ratio (p=0.042) with modest enrichment of activated CD8+ T cells after treatment, supporting a more pro-inflammatory TME. Conclusions: The neoadjuvant combination of canakinumab (αIL-1β) and spartalizumab (αPD-1) is well-tolerated, feasible, and demonstrated promising clinical activity with no progression of disease observed in a localized ccRCC population at high risk of recurrence. Correlative analyses demonstrated that combined IL-1β and PD-1 blockade reprograms immunosuppressive TAMs, providing evidence that dual IL-1β and PD-1 inhibition can overcome myeloid-driven resistance in ccRCC. Clinical Trial Information: NCT04028245 Citation Format: Patrick J. McCann, Aleksandar Obradovic, Casey R. Ager, David H. Aggen, Catherine S. Spina, Chelsea L. Rahiman, Kaitlyn R. Campbell, Caroline Laplaca, Peyton C. Johnston, Amanda Kim, Katherine Gomez, Kriti Bagri Manjrekar, Mark N. Stein, Charles G. Drake, Karie Runcie, Matthew Dallos. Neoadjuvant IL-1β and PD-1 inhibition in localized clear-cell renal cell carcinoma: Clinical and correlative analyses of the phase 1b SPARC-1 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr CT017.

OBJECTIVE Dural arteriovenous fistulas (dAVFs) are rare cerebrovascular anomalies. Tentorial dAVFs (TDAVFs) have more aggressive features, making them prone to symptomatic presentations and hemorrhage. TDAVFs are heterogenous and require tailored surgical approaches. Presented is a multicenter analysis of TDAVF surgical outcomes. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) consortium compiled data on dAVFs from 16 international centers from 1990 to 2021 retrospectively. Microsurgical treatment success was defined as angiographically confirmed complete obliteration of the fistula or discontinuation of cortical venous drainage (CVD) in high-grade TDAVFs. TDAVF subtypes and tailored surgical approaches were reviewed. RESULTS Of 1360 patients in CONDOR, 161 had TDAVFs and 27% (44/161) of these patients underwent surgical management, with the majority (52% [23/44]) receiving surgery as a salvage treatment following failed embolization. The mean age (SD) of this cohort was 56 (15) years, and 68% (30/44) were male. In total, 91% (40/44) of surgically treated patients presented with aggressive symptoms: 64% (28/44) presented with hemorrhage and 27% (12/44) with nonhemorrhagic neurological deficit (NHND). The median (IQR) duration from symptom onset to diagnosis was 1 (1–4) day. The median time (IQR) between diagnosis and surgery was 15 (3–80) days. Surgical approaches varied across the cohort, with the retrosigmoid being the most common (44% [18/41]), followed by the midline suboccipital (24% [10/41]) and occipital (15% [6/41]) approaches. Perioperative complications occurred in 11% (5/44) of cases, as well as permanent neurological deficits in 2% (1/44). Surgical success was achieved in 90% of patients (38/42). During the mean 3-year follow-up, 2 patients experienced a recurrence of their fistula including representation of CVD (2/38 [5%]) and 1 patient had a new NHND (1/43 [2%]). Shorter symptom duration was significantly associated with success (15.6 vs 181.5 days, p = 0.001). Primary versus salvage microsurgery showed no difference in outcomes. Both patients with recurrent fistula were effectively treated with Gamma Knife radiosurgery. CONCLUSIONS Resection is safe and durable for the treatment of TDAVF not otherwise amenable to embolization. It can achieve a high degree of success with a low rate of perioperative complications and permanent neurological deficits, benefits far exceeding the risks associated with TDAVF natural history or management with less effective modalities.

COASY-related disorders (CRDs) are a spectrum of autosomal recessive conditions caused by the dysfunction of CoA synthase, an enzyme responsible for the final steps of CoA synthesis. Clinical manifestations of CRDs are highly variable, ranging from perinatal lethal pontocerebellar hypoplasia to childhood-onset neurodegenerative brain iron accumulation, which is often recognized after clinical regression. Recent reports have described a few individuals with CRD who screened positive for carnitine palmitoyltransferase-I deficiency by newborn screening (NBS). However, heterogeneous clinical presentations, conflicting biochemical/molecular sequencing of CPT1A, and a lack of metabolic characterization have led to lengthy, costly diagnostic journeys. To address some of these aspects, this investigation retrospectively evaluated NBS acylcarnitine patterns in five CRD cases using Collaborative Laboratory Integrated Reports (CLIR). A total of 25 metabolites/ratios were identified to deviate significantly from reference ranges and were primarily composed of elevated free carnitine and reduced long-chain acylcarnitine levels. While low acylcarnitine concentrations are often not reported due to a lack of lower reference cutoffs, ratios involving these metabolites relative to short-chain acylcarnitines could aid in identifying CRD cases via NBS. When comparing this pattern to CPT-Ia cases, we confirmed a nearly identical acylcarnitine pattern between these, and thus support the need to consider CRD in cases with NBS results suggestive of CPT-Ia. This study is the first case series to characterize NBS patterns in patients with CRD and highlights the unique opportunity for early detection, particularly in cases that are neonatally asymptomatic and have unremarkable confirmatory biochemical results.

Background: Religious affiliation has traditionally served as a coping strategy during stressful events such as the COVID-19 pandemic. Pregnant women faced heightened stress during the pandemic due to concerns about their health as well as that of their fetus. This study examined the prevalence of self-reported religious affiliation among SARS-CoV-2-positive pregnant women and investigated differences in psychiatric diagnoses and pregnancy outcomes based on religious affiliation. Methods: The study included all asymptomatic or mildly symptomatic SARS-CoV-2-positive pregnant women who received care at the Mayo Health System from March 2020 through October 2021 and completed the routine religious affiliation questionnaire. Those selecting “none” were categorized as having no religious affiliation (RA−), whereas those selecting a specific religion were categorized as religiously affiliated (RA+). Results: Among 609 women, 49.6% were RA+ and 50.4% were RA−. RA+ women were more likely to be white, married, college-educated, and have fewer prior abortions. There were no significant differences in rates of depression, anxiety, psychotropic medication use, substance use, or pregnancy and labor complications between RA+ and RA− groups. Conclusions: Half of the women in this cohort reported no religious affiliation. Previously reported protective associations between religiosity and mental health were not observed when religious affiliation alone was examined.

Background: Localized soft tissue sarcoma (STS) is primarily treated with surgical resection with or without radiotherapy (RT), while the role of chemotherapy (CT) as a radiosensitizer remains unclear. We report our single-institution experience with combined chemoradiotherapy (CCRT) in treating localized STS. Methods: We conducted a retrospective analysis of patients with localized STS treated at Mayo Clinic with mitomycin, cisplatin, and doxorubicin (MitoAP) concurrently with RT between 1/1/85 and 12/12/19. Results: We identified 179 patients (median age 58 years; median tumor size 9.5 cm), with 83.8% of tumors located in the extremities or trunk. Among them, 77.1% received perioperative CT in addition to CCRT, with 95% of those treated in the neoadjuvant setting. Median RT dose was 50 Gray. The 5-year disease-specific survival (DSS) was 77.9% (95% confidence interval, CI: 70.8–83.4%). The addition of perioperative CT to CCRT was associated with improved DSS compared with CCRT alone (p = 0.01, Hazard Ratio, HR: 0.48, 95% CI: 0.27–0.85). Median post-CCRT tumor viability was 30% and did not differ by CT use (p = 0.39), but varied significantly by histology (p < 0.001). Conclusions: Our institutional protocol utilizing two cycles of MitoAP with RT was well tolerated. DSS in our cohort was similar to historical data using perioperative RT alone, suggesting no clear benefit from CCRT. However, the majority of patients in our cohort were classified as high risk, which may have attenuated a potential survival benefit in the absence of appropriate comparative controls. Furthermore, additional perioperative CT to CCRT was associated with improved DSS and differential histology-specific responses in tumor viability, suggesting that a more aggressive neoadjuvant and perioperative approach may be beneficial in selected patients.

Diagnosing rare genetic diseases remains a major challenge despite widespread clinical testing. Long-read RNA sequencing (RNA-seq) offers a powerful approach to capturing the effects of genetic variants on the transcriptome, yet challenges with sequencing coverage, cost, tissue selection, and scalability have limited its clinical adoption. To address this, we developed STRIPE (Sequencing Targeted RNAs Identifies Pathogenic Events), a targeted long-read RNA-seq–based strategy for rare disease diagnosis and variant interpretation. STRIPE enables deep sequencing of full-length transcripts for any customized disease-specific gene panel such that a wide range of clinically informative readouts, including transcript aberrations and sequence variants, can be detected at haplotype-level resolution. Applying STRIPE to 88 individuals spanning two major rare disease groups, we accurately reidentified known pathogenic variants and revealed their transcript consequences, including many unexpected ones. For 8 of 15 splice site region variants, we observed more complex RNA processing defects beyond single exon skipping or cryptic splice site activation. Notably, we find that donor splice site variants frequently activate cryptic intronic polyadenylation sites, leading to premature transcript termination. Leveraging unique strengths of long-read RNA-seq, STRIPE also resolved variants of uncertain significance and uncovered disease-causing variants in five previously undiagnosed individuals. Overall, STRIPE is a powerful, adaptable, and scalable strategy with broad potential to improve clinical variant interpretation and advance genetic diagnosis of rare diseases.

Abstract Purpose To report historical patterns of pharmaceutical expenditures, to identify factors that may influence future spending, and to predict growth in drug spending in 2026 in the United States, with a focus on the nonfederal hospital and clinic sectors. Methods Historical patterns were assessed by examining data on drug purchases from manufacturers using the IQVIA National Sales Perspectives database. Factors that may influence drug spending in hospitals and clinics in 2026 were reviewed—including new drug approvals, patent expirations, and potential new policies or legislation. Focused analyses were conducted for biosimilars, cancer drugs, endocrine drugs, generics, specialty drugs, and vaccines. For nonfederal hospitals, clinics, and overall (all sectors), estimates for growth of pharmaceutical expenditures in 2026 were made based on a combination of quantitative analyses and expert opinion. Results In 2025, overall pharmaceutical expenditures in the US grew 12.7% compared to 2024, for a total of $915.2 billion. Utilization (a 9.3% increase) drove this increase, while growth due to new drugs (0.9%) and price increases (1.2%) had a modest impact. Tirzepatide was the new top drug in 2025, followed by semaglutide and apixiban. Drug expenditures were $42.9 billion (a 9.6% increase) and $190.5 billion (a 19.0% increase) in nonfederal hospitals and in clinics, respectively. In clinics, volume drove drug expense growth, contributing with a 13.6% increase, while price and new drugs each contributed with a 2.7% increase. In nonfederal hospitals, expenditure growth was driven by increases in volume (4.6%), new products (3.7%), and prices (1.5%). Several new drugs that will influence spending are expected to be approved in 2026. Specialty, endocrine, and cancer drugs will continue to drive expenditures. Conclusion For 2026, we expect overall prescription drug spending to rise by 10.0% to 12.0%, whereas in clinics and hospitals we anticipate increases of 14.0%-16.0% and 4.0%-6.0%, respectively, compared to 2025. These national estimates of future pharmaceutical expenditure growth may not be representative of any health system because of the myriad of local factors that influence actual spending