Ou, Fang‐Shu

Abstract Background Atezolizumab plus bevacizumab (A/B) received FDA approval as the first-line therapy for patients with advanced hepatocellular carcinoma (HCC) in 2020. However, optimal subsequent treatment options are unclear. Here, we describe clinical outcomes of advanced HCC patients following first-line treatment with A/B. Patients and Methods We conducted a multi-site analysis of patients with HCC treated with first-line A/B between January 2018 and December 2022 at Mayo Clinic. This study cohort included all patients receiving second-line systemic therapy after A/B. Median overall survival (OS) and time-to-treatment discontinuation (TTD) were estimated using the Kaplan-Meier method. Child Pugh (CP) scores are also described at diagnosis, prior to first line, and prior to second-line therapy. Results Of the 342 patients who received A/B, 107 (31.3%) received second-line treatments including anti-VEGF therapy or immune checkpoint inhibitor (ICI) and were included in the final analysis. Median OS for all patients was 11.1 months from initiation of second-line therapy. Median OS was 10.7 months (95% CI: 7.2-12.8) and 15.7 months (95%CI: 6.8-NE) for those receiving anti-VEGF inhibitors and ICI ( P = .50). Median TTD for second-line therapies was 2.4 months (95% CI: 1.7-3.3) and 2.6 months (95% CI: 1.5-5.1) for anti-VEGF inhibitors and ICI, respectively (P = .87). In multivariate analyses, CP was significantly associated with survival. Conclusion Following first-line A/B treatment, there is no statistically significant difference in survival between ICI and anti-VEGF therapy, nor in time to treatment discontinuation. CP score remains an important prognostic tool.

Abstract Background A plant-based diet is associated with better survival among patients with nonmetastatic colorectal cancer (CRC), but its association in metastatic CRC is unknown. Methods Using an National Cancer Institute–sponsored trial (CALGB/SWOG 80405), we included 1284 patients who completed validated food frequency questionnaires at the initiation of metastatic CRC treatment. We calculated 3 indices: overall plant-based diet index (PDI), which emphasized consumption of all plant foods while reducing animal food intake; healthful plant-based diet index (hPDI), which emphasized consumption of healthful plant foods such as whole grains, fruits, and vegetables; and unhealthful plant-based diet index (uPDI), which emphasized consumption of less healthful plant foods such as fruit juices, refined grains, and sugar-sweetened beverages. We estimated the associations of 3 indices (quintiles) with overall survival (OS) and progression-free survival (PFS) using multivariable Cox proportional hazards regression. Results We observed 1100 deaths and 1204 progression events (median follow-up = 6.1 years). Compared with the lowest quintile, patients in the highest quintile of PDI had significantly better survival (hazard ratio [HR] for OS = 0.76 [0.62-0.94], Ptrend = .004; PFS = 0.81 [0.66-0.99], Ptrend = .09). Similar findings were observed for hPDI (HR for OS = 0.81 [0.65-1.01], Ptrend = .053; PFS = 0.80 [0.65-0.98], Ptrend = .04), whereas uPDI was not associated with worse survival (HR for OS = 1.16 [0.94-1.43], Ptrend = .21; PFS = 1.12 [0.92-1.36], Ptrend = .42). Conclusions Our study suggests that a plant-based diet, especially when rich in healthful plant foods, is associated with better survival among patients with metastatic CRC. The cause of survival benefits warrants further investigation.

A clinical trial represents a large commitment from all individuals involved and a huge financial obligation given its high cost; therefore, it is wise to make the most of all collected data by learning as much as possible. A multistate model is a generalized framework to describe longitudinal events; multistate hazards models can treat multiple intermediate/final clinical endpoints as outcomes and estimate the impact of covariates simultaneously. Proportional hazards models are fitted (one per transition), which can be used to calculate the absolute risks, that is, the probability of being in a state at a given time, the expected number of visits to a state, and the expected amount of time spent in a state. Three publicly available clinical trial datasets, colon, myeloid, and rhDNase, in the survival package in R were used to showcase the utility of multistate hazards models. In the colon dataset, a very well-known and well-used dataset, we found that the levamisole+fluorouracil treatment extended time in the recurrence-free state more than it extended overall survival, which resulted in less time in the recurrence state, an example of the classic “compression of morbidity.” In the myeloid dataset, we found that complete response (CR) is durable, patients who received treatment B have longer sojourn time in CR than patients who received treatment A, while the mutation status does not impact the transition rate to CR but is highly influential on the sojourn time in CR. We also found that more patients in treatment A received transplants without CR, and more patients in treatment B received transplants after CR. In addition, the mutation status is highly influential on the CR to transplant transition rate. The observations that we made on these three datasets would not be possible without multistate models. We want to encourage readers to spend more time to look deeper into clinical trial data. It has a lot more to offer than a simple yes/no answer if only we, the statisticians, are willing to look for it.

PURPOSE Thrombocytopenia is a relatively common dose-limiting toxicity during peptide receptor radionuclide therapy (PRRT) in patients with NET. Although uncommon, some patients develop persistent cytopenia and eventually therapy-related myeloid neoplasm (t-MN), which has a dismal prognosis. As the indications for PRRT are expanding, it is important to investigate factors that may predict cytopenias during/after PRRT. We prospectively evaluated the prevalence of clonal hematopoiesis (CH) and cytopenia in patients with NET undergoing PRRT. MATERIALS AND METHODS Patients with metastatic NET with plan to receive four cycles of lutetium-177 were enrolled. CH was evaluated before PRRT using a panel of 220 genes with a targeted depth of ≥1,000×. Patients were followed during PRRT and every 3 months thereafter. RESULTS Of 37 patients enrolled, the median age was 68 years and 51.4% were male. Previous treatment exposures included alkylating agents in 30%, platinum agents in 8%, and external radiation in 13%. CH was detected in 35.1% using a variant allele frequency (VAF) cutoff of ≥2% and 45.9% with a VAF of ≥1%. The most common mutations were in age-related genes ( DNMT3A, TET2). CH was not associated with anemia or neutropenia; however, it was associated with lower platelet count at baseline and more time spent in a thrombocytopenic state during/after PRRT. Five patients had bone marrow biopsies (BMBs) because of sustained hematologic dysfunction post-PRRT, and of those, diagnoses included clonal cytopenia of undetermined significance (CCUS) in three and idiopathic cytopenia of undetermined significance (ICUS) in two. CONCLUSION CH is present in 35.1% of patients with NET and is associated with thrombocytopenia risk during PRRT. Future studies with long-term follow-up will delineate whether CH might be a predictor for higher risk of t-MN after PRRT.

3588 Background: The brain-gut axis, a bidirectional network between the central and enteric nervous systems, plays a critical role in modulating the gastrointestinal tract function. Increasing evidence suggests that neuronal signaling molecules can promote gastrointestinal cancers; however, the mechanisms remain unclear. Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter and dysregulated GABA signaling has been found in CRC, affecting both tumor and tumor microenvironment. Here, we investigated the association between tumor GABA pathway gene expression and first-line treatment outcomes in mCRC. Methods: We evaluated the impact of the expression of 25 genes in the GABA pathway ( GABBR1, GABBR2, GABRA1, GABRA2, GABRA4, GABRA5, GABRA6, GABRB1, GABRB3, GABRD, GABRE, GABRG1, GABRG2, GABRG3, GABRQ, GABRR1, GABRR2, ABAT, ALDH5A1, GAD1, GAD2, SLC6A1, SLC6A13, SLC6A11, SLC6A12) on treatment outcomes (overall survival: OS; progression free survival: PFS) of 433 pts enrolled in the randomized, phase III CALGB/SWOG 80405 trial. RNA extracted from FFPE tumor samples was sequenced using the HiSeq 2500 (Illumina). The associations between gene expression (continuous, per standard deviation increase) and outcomes were assessed via the multivariable Cox proportional framework, with hazard ratios (HR) and 95% confidence intervals (CI) computed. The likelihood ratio test was used for interaction tests. False discovery rate (FDR) was controlled at 5% with the Benjamini-Hochberg method. Results: Overall, low GAD1 (encoding for glutamate decarboxylase 1, the enzyme responsible for catalyzing the production of GABA from L-glutamic acid) was associated with longer PFS (HR: 1.26, 95% CI [1.13, 1.41], P = 3.2E-05) and OS (HR 1.27 [1.13, 1.43], P = 5.9E-05) across all treatment arms. High ABAT (encoding for the aminotransferase responsible for GABA catabolism) was also associated with longer OS (HR 0.81 [0.72, 0.91], P = 6E-04). To evaluate the predictive value, interactions with targeted therapies bevacizumab (n = 226) vs cetuximab (n = 207) were tested. We found significant interactions for PFS with ABAT ( P= 0.0017) and OS with SLC6A13 ( P= 0.0014 ).In pts treated with cetuximab, high ABAT expression was significantly associated with longer PFS (HR 0.73 [0.61, 0.87], P = 2.8E-04), and high SLC6A13 was marginally associated with worse OS (HR 1.18 [1.00, 1.39], P = 0.052). We did not observe similar associations in pts treated with bevacizumab. Conclusions: Our results highlight a potential role for GABA signaling in affecting mCRC treatment outcomes, suggesting that GABA pathway genes may be promising novel predictive and prognostic biomarkers and supporting the rationale to investigate GABA as a target for drug development. ClinicalTrials.gov Identifier: NCT00265850

3144 Background: Longitudinal brain structure changes across the lifespan are associated with neurodegenerative disorders. We previously showed that genetic variants in dopamine and Parkinson’s disease genes are predictive and prognostic in mCRC. Indeed, the brain-gut axis is emerging as a critical player in CRC biology. Hence, we investigated whether the tumor gene expression of 3 metabolic genes involved in brain development and aging could affect treatment response in patients enrolled in the CALGB/SWOG 80405 trial. Methods: 433 mCRC pts treated with either bevacizumab (bev, n = 226) or cetuximab (cet, n = 207) in combination with first-line chemotherapy were included in the analysis. RNA was isolated from FFPE tumor samples and sequenced on the HiSeq 2500 (Illumina). Overall survival (OS) and progression-free survival (PFS) were compared between groups of pts categorized by tertiles of expression of 3 genes: APOE, DACH1, and GPR139. Likelihood ratio tests, hazard ratios and 95% confidence intervals were computed from multivariate Cox proportional hazards models, adjusting for age, sex, ethnicity, ECOG PS, tumor location, number of metastatic sites, KRAS, MSI status, and treatment. Logrank P-values describe differences without adjustment for patient characteristics. Results: Both APOE and DACH1 (but not GPR139) met the 0.05 false discovery rate threshold for association with both PFS ( P = .00085, P = .015) and OS ( P = .021, P = .021, respectively) in the full Cox models. In cet-treated pts, APOE-high (H) showed significantly shorter PFS (median 9.2 vs 11.8 vs 13.0 months (mo), high vs low (as reference) logrank P = .0021) and OS (median 21.9 vs 35.8 vs 34.6 mo; logrank P = .0017) compared to APOE-median and -low, respectively. Opposite results were observed for DACH1, where DACH1-H tumors had longer PFS (median 14.5 vs 10.6 vs 8.07 mo; logrank P = .0011) and OS (median 39.4 vs 30.9 vs 21.5 mo; logrank P = .0021) when treated with cet. In bev-treated pts, similar results were observed with APOE-H showing shorter OS (median 25.8 vs 26.3 vs 37.5 mo; logrank P = .0016) and DACH1-H longer OS (median 36.5 vs 28.3 vs 22.4 mo; logrank P = .0017). No significant gene-treatment interaction was observed for either gene for PFS and OS. Conclusions: The tumor expression of metabolic genes associated with changes in the brain structure was prognostic in mCRC pts treated with first-line therapy. Notably, APOE and DACH1 have been recently reported to play a role in CRC where APOE overexpression has been associated with aggressive biological behavior whereas DACH1 has been shown to suppress CRC cell growth and invasion. Our results support this evidence and suggest that further investigation into the role of APOE and DACH1 in CRC biology and into their potential as targets for drug development is warranted. Trial Identifier: NCT00265850.

3523 Background: Evidence suggests neurotransmitter signaling may play a crucial role in tumorigenesis of gastrointestinal (GI) cancers, including migration, proliferation, and apoptosis, as well as angiogenesis and the microenvironment. We developed and applied a strategy to identify upstream regulators of neurotransmitters and their associations with patient outcomes. Methods: Prior literature yielded 85 neurotransmitter signaling genes mapped to RNA-seq gene expression in tumor tissue from 545 patients with mCRC enrolled in the phase III CALGB/SWOG 80405 trial. These samples were also sequenced by FoundationOne CDx for DNA damage. Using Cox proportional hazards regression, we identified a subset of CDx genes associated with overall survival (OS) or progression-free survival (PFS). We extended the Causal Inference Test (CIT) for time-to-event data and identified a subset of the 85 signaling genes consistent with mediation of DNA mutation effects on OS and PFS. Another CIT analysis identified potential upstream neurotransmitter regulators, gene expression mediators of mutation effects on the signaling genes. Top genes were then assessed in whole-transcriptome sequencing (WTS) expression data with Caris MI profile collected from 398 patients with advanced CRC enrolled in the MONSTAR-SCREEN-2 trial. Results: At the 0.05 alpha level, we identified 20 signaling genes with gene expression associated with PFS and/or OS, and 68 genes with evidence of DNA mutations associated with PFS and/or OS. False discovery rate (FDR) < 0.05 was applied to filter the 56,674 expression features on PFS and OS associations, yielding 173 unique genes as possible mediators. The CIT yielded 53 putative mediators at FDR < 0.05, suggesting upstream regulation of neurotransmitter signaling. Five genes were identified as targeting at least 8 signaling genes each, PIGU, ANO9, LY6G6D, and GPR160, and FSCN1, where the first 4 are favorable and only FSCN1 is a poorer prognostic. Following up on these 5 genes in MONSTAR-SCREEN-2 by dichotomizing at the median value of WTS expression, 3 were nominally associated with OS, PIGU ( P = 0.050; HR, 0.59; 95%CI, 0.34-1.00), ANO9( P = 0.029; HR, 0.55; 95%CI, 0.32-0.95), LY6G6D( P = 0.0024; HR, 0.44; 95%CI, 0.25-0.76), and FSCN1 was suggestive ( P = 0.079; HR, 1.62; 95%CI, 0.94-2.77), with direction of effects in agreement with 80405 results for all four. Conclusions: Our novel approach identified previously unknown upstream regulators of neurotransmitter signaling associated with treatment outcomes in mCRC. PIGU, FSCN1, and LY6G6D have been suggested in prior literature as targets for CRC and ANO9 has been suggested as a target for GI cancer. These results bolster the strategy of using mediation analysis with large-scale molecular data to identify new therapeutic targets in CRC. NCT00265850.

e15146 Background: Wnt/ß-catenin signaling dysregulation is found in approximately 25% of hepatocellular carcinoma (HCC) patients. The impact of B-catenin activation on HCC overall survival has remained controversial. Prior studies suggest activating CTNNB1 mutations may predict for immunotherapy (IO) resistance while others did not corroborate this finding. Here we describe the clinical outcomes of advanced HCC patients (pts) with CTNNB1 (+) and without CTNNB1 (-) mutations treated with novel first line IO/anti-VEGF therapies. Methods: We conducted a multicenter, retrospective analysis of pts with HCC who had molecular analysis performed between 2019 and 2023 at Mayo Clinic in Minnesota, Arizona, and Florida. The study was reviewed and approved by the IRB. Clinical and molecular features were compared descriptively. The primary outcomes were time to treatment failure (TTF), defined as time from first-line treatment initiation to off treatment or death, and overall survival (OS), defined as time from first-line treatment initiation to death, compared between the two cohorts using the Kaplan-Meier method. Results: We identified 29 CTNNB1+ and 62 CTNNB1- (wt) pts with HCC. Median age at diagnosis was 66 (range 30-86), 80 (88%) were Caucasian, 68 (75%) were male gender, and 22 (24%) had etiology as hepatitis B/hepatitis C, 82 (90%) were Child-Pugh A and 77 (85%) were Barcelona Clinic Liver Clinic (BCLC)=C at diagnosis. Eighteen (90%, n=20) CTNNB 1+ pts received first-line IO (Atezolizumab/bevacizumab [AB]) vs 39 (72%, n=54) in CTNNB1- pts. All pts were microsatellite stable (MSS). CTNNB1+ had a similar median tumor mutational burden (TMB), higher rate of TERT co-mutation, and lower rate of TP53 co-mutation (table) compared to CTNNB-. Of 57 AB pts, 5 (27%) of CTNNB1 + had an objective response, compared to 6 (16.7%) CTNNB1- pts. Time to treatment failure with first-line AB and overall survival were similar between the two cohorts (Table). Conclusions: Our study suggests CTNNB1 status is not prognostic in HCC pts receiving IO based therapy. Prospective study is warranted to further investigate predictive biomarkers for HCC sensitivity to immune checkpoint inhibitors and VEGF-targeted therapy. [Table: see text]