Citations

4157 Background: IDH1/2 mutations occur in ~25% of cholangiocarcinomas (CCAs). Preclinical studies suggest synergy between PARP inhibition and PD-L1 blockade. We previously conducted a phase II trial of olaparib plus durvalumab in advanced IDH -mutant CCA. We report matched baseline tissue and serial cell-free DNA (cfDNA)-based correlative analysis of pts samples. The primary objective was to develop a cfDNA methylome signature as a non-invasive biomarker. Methods: This single-arm, open-label phase II study (NCT03991832) enrolled patients with unresectable/metastatic IDH -mutant CCA and ≤2 prior lines of systemic therapy. Patients received olaparib 300 mg orally twice daily and durvalumab 1500 mg IV every 4 weeks. Blood samples were collected at baseline and monthly while on treatment for planned correlatives to examine R2HG, S2HG, and artemin levels using HPLC (High-Performance Liquid Chromatography). Cell-free methylated DNA immunoprecipitation and high-throughput sequencing (cfMeDIP-seq) was performed on pts cfDNA samples and case-matched IDH -wildtype pts. Formalin-fixed, paraffin-embedded blocks of baseline tumor biopsies were used for multispectral fluorescent IHC (FL-IHC) using a 6-marker panel composed of pan-cytokeratin, CD4, CD8, CD163, PD-L1, and CD68. Results: Ten patients were enrolled (median age 63.5 y; 50% female; 90% received prior platinum). Median treatment duration was 1.95 mo (range 1.8–13.5). No complete or partial responses were observed. DCR was 30% (3 patients with stable disease); one patient remained on therapy for 13.5 mo before progression. Median PFS was 1.97 mo (95% CI 1.73–3.93). HPLC from baseline plasma showed lower baseline artemin levels correlated with stable disease (p=0.038), while R2HG/S2HG ratios showed no association with outcome. FL-IHC showed enriched immune cell populations, specifically CD4 + T cells (p=0.0032) and a trend for CD68 + macrophages (p=0.062), in the tumor stroma compared with tumor core. 54 plasma samples (from 8 patients) were profiled with cfMeDIP-seq along with 8 IDH -wildtype controls. Using top 100 differentially methylated regions, the circulating tumour DNA methylome exhibited a highly specific signature, accurately discriminating IDH -mutant and IDH -wildtype CCA regardless of treatment status. The specific differentially methylated gene pathways between groups were comprehensively examined in both on-treatment and baseline plasma samples. Conclusions: Advanced IDH -mutant CCA harbors an immune-excluded phenotype, which may underlie primary resistance to immunotherapy. Plasma cfDNA methylome signature can accurately discriminate CCA with IDH mutations. Clinical trial information: NCT03991832 .

ABSTRACT Background Immune checkpoint inhibitors (ICIs) have emerged as promising agents for the management of advanced HCC. By reducing tumour burden, ICIs may serve as a downstaging/bridging tool to improve transplant candidacy. The aim of this study was to assess the safety of patients receiving pre‐LT ICIs. Methods Multicenter, retrospective cohort study from January 2018 to December 2024, including 48 patients who received ICIs prior to LT (ICI cohort). A control cohort (non‐ICI cohort) was built (1:3) using propensity score matching including 144 patients who underwent LT for HCC without prior ICI. Results Within the ICI cohort ( N = 48) rejection occurred in 9 patients (18.8%), all biopsy‐proven, with a median onset of 31 days post‐LT (12.0–182.0). The median washout period was 60 days (13–96). Patients experiencing rejection had shorter washout periods ( p = 0.029). All rejection episodes were successfully managed; two were steroid‐resistant, one requiring re‐transplantation. There were no rejection‐related deaths. Of the 5 patients with HCC recurrence, 60% received ICI for < 90 days ( p = 0.027). Comparison between the ICI and non‐ICI cohort revealed no significant differences in rejection rates (18.8% vs. 19.4%, p = 0.916), graft failure, HCC recurrence, or overall mortality. Overall survival (OS) did not differ between ICI and non‐ICI patients ( p = 0.625) or between those with and without rejection ( p = 0.119). Rejection was not associated with increased mortality, with deaths primarily attributed to infection or HCC recurrence. Conclusion Our results demonstrate that rejection rates were similar in patients receiving ICIs pre‐LT and it can be safely managed.

Abstract Background and Aims Following liver resection (LR) for HCC, the likelihood of survival is dynamic, in that multiple recurrences and/or metastases are possible, each having variable impacts on outcomes. We sought to evaluate the natural progression, pattern, and timing of various disease states after LR for HCC using multistate modeling and to create a practical calculator to provide prognostic information for patients and clinicians. Approach and Results Adult patients undergoing LR for HCC between January 2000 and December 2018 were retrospectively identified at a single center. Multistate analysis modeled post‐LR tumor progression by describing transitions between distinct disease states. In this model, the states included surgery, intrahepatic recurrence (first, second, third, fourth, fifth), distant metastasis with or without intrahepatic recurrence, and death. Of the 486 patients included, 169 (34.8%) remained recurrence‐free, 205 (42.2%) developed intrahepatic recurrence, 80 (16.5%) developed distant metastasis, and 32 (7%) died. For an average patient having undergone LR, there was a 33.1% chance of remaining disease‐free, a 31.0% chance of at least one intrahepatic recurrence, a 16.3% chance of distant metastasis, and a 19.8% chance of death within the first 60 months post‐LR. The transition probability from surgery to first intrahepatic recurrence, without a subsequent state transition, increased from 3% (3 months) to 17.4% (30 months) and 17.2% (60 months). Factors that could modify these probabilities included tumor size, satellite lesions, and microvascular invasion. The online multistate model calculator can be found on https://multistatehcc.shinyapps.io/home/. Conclusions In contrast to standard single time‐to‐event estimates, multistate modeling provides more realistic prognostication of outcomes after LR for HCC by taking into account many postoperative disease states and transitions between them. Our multistate modeling calculator can provide meaningful data to guide the management of patients undergoing postoperative surveillance and therapy.

Abstract Purpose: DNA topoisomerase inhibitors are commonly used for treating small-cell lung cancer (SCLC). Tyrosyl-DNA phosphodiesterase (TDP1) repairs DNA damage caused by this class of drugs and may therefore influence treatment outcome. In this study, we investigated whether common TDP1 single-nucleotide polymorphisms (SNP) are associated with overall survival among SCLC patients. Experimental Design: Two TDP1 SNPs (rs942190 and rs2401863) were analyzed in 890 patients from 10 studies in the International Lung Cancer Consortium (ILCCO). The Kaplan–Meier method and Cox regression analyses were used to evaluate genotype associations with overall mortality at 36 months postdiagnosis, adjusting for age, sex, race, and tumor stage. Results: Patients homozygous for the minor allele (GG) of rs942190 had poorer survival compared with those carrying AA alleles, with a HR of 1.36 [95% confidence interval (CI): 1.08–1.72, P = 0.01), but no association with survival was observed for patients carrying the AG genotype (HR = 1.04, 95% CI, 0.84–1.29, P = 0.72). For rs2401863, patients homozygous for the minor allele (CC) tended to have better survival than patients carrying AA alleles (HR = 0.79; 95% CI, 0.61–1.02, P = 0.07). Results from the Genotype Tissue Expression (GTEx) Project, the Encyclopedia of DNA Elements (ENCODE), and the ePOSSUM web application support the potential function of rs942190. Conclusions: We found the rs942190 GG genotype to be associated with relatively poor survival among SCLC patients. Further investigation is needed to confirm the result and to determine whether this genotype may be a predictive marker for treatment efficacy of DNA topoisomerase inhibitors. Clin Cancer Res; 23(24); 7550–7. ©2017 AACR.

Abstract Introduction: DNA topoisomerase inhibitors (e.g. etoposide, irinotecan, teniposide, topotecan) are commonly used for treating small cell lung cancer (SCLC). Tyrosyl-DNA phosphodiesterase (TDP1) plays a role in repairing DNA damage caused by DNA topoisomerase inhibitors and it is believed to be responsible for resistance to this class of drugs. The purpose of this study was to determine whether common TDP1 polymorphisms are associated with overall survival among SCLC patients. Method: Two common TDP1 SNPs (rs942190 and rs2401863, r2(European)=0.63 and r2(East Asian)=0.26) were analyzed in 898 patients from 10 studies in the International Lung Cancer Consortium, conducted in the U.S., Canada, Japan, Italy, Spain and the United Kingdom. Genotype data were obtained from either the OncoArray Consortium or other existing genome-wide association studies. Cox proportional hazard regression models with robust standard error were used to evaluate genotype associations for overall survival at 36 months post-diagnosis, adjusting for age, sex, race and tumor stage. Results: Patients homozygous for the minor allele (GG) of TDP1 SNP rs942190 were associated with poorer survival compared to those carrying both major alleles (AA), with a hazard ratio (HR) of 1.36 (95% confidence interval (CI): 1.07-1.72, p-value=0.01), but there was no association with survival for patients with the heterozygous genotype (HR=1.02, 95% CI: 0.83-1.27, p-value=0.83). For rs2401863, patients carrying both minor alleles (CC) tended to have better survival than patients carrying AA alleles, but this was within the limits of chance given no significant association (HR=0.79, 95% CI: 0.61-1.02, p-value=0.07). In addition, multi-tissue expression quantitative trait loci (eQTL) analyses from the Genotype-Tissue Expression Project indicated a potential effect of rs942190 on lung tissue, with higher TDP1 gene expression for the GG than AG or AA genotypes. Conclusion: We found that among SCLC patients the TDP1 rs942190 GG genotype was associated with poor overall survival. Further study could determine if this genotype can serve as a predictive marker for the treatment efficacy of DNA topoisomerase inhibitors in SCLC. Citation Format: Pawadee Lohavanichbutr, Lori C. Sakoda, Christopher I. Amos, Susanne M. Arnold, David C. Christiani, Michael P. Davies, John K. Field, Eric B. Haura, Rayjean J. Hung, Takashi Kohno, Maria Teresa Landi, Geoffrey Liu, Yi Liu, Michael W. Marcus, Grainne M. O'Kane, Matthew B. Schabath, Kouya Shiraishi, Stacey A. Slone, Adonina Tardón, Ping Yang, Kazushi Yoshida, Ruyang Zhang, Xuchen Zong, Noel S. Weiss, Chu Chen. Common TDP1 polymorphisms in relation to survival among small cell lung cancer patients in a multicenter study from the International Lung Cancer Consortium [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2248. doi:10.1158/1538-7445.AM2017-2248