18F-BMS-986229 PET to Assess Programmed-Death Ligand 1 Status in Gastroesophageal Cancer

Anti-programmed death 1 (PD-1) inhibitors are the standard of care for advanced gastroesophageal cancer. Although recommendations and approval by regulatory agencies are often based on programmed death ligand 1 (PD-L1) expression, pathologic assessments of PD-L1 status have several limitations. Single-site biopsies do not adequately capture disease heterogeneity within individual tumor lesions or among several lesions within the same patient, the PD-L1 combined positive score is a dynamic biomarker subject to evolution throughout a patient's disease course, and repeated biopsies are invasive and not always feasible. Methods: This was a prospective pilot study of the PD-L1-targeting radiotracer, 18F-BMS-986229, with PET imaging (PD-L1 PET) in patients with gastroesophageal cancer. Patients were administered the 18F-BMS-986229 radiotracer intravenously at a dose of 370 MBq over 1-2 min and underwent whole-body PET/CT imaging 60 min later. The primary objective of this study was to evaluate the safety and feasibility of 18F-BMS-986229. The trial is registered with ClinicalTrials.gov (NCT04161781). Results: Between February 3, 2020, and February 2, 2022, 10 patients with gastroesophageal adenocarcinoma underwent PD-L1 PET. There were no adverse events associated with the 18F-BMS-986229 tracer, and imaging did not result in treatment delays; the primary endpoint was achieved. Radiographic evaluation of PD-L1 expression was concordant with pathologic assessment in 88% of biopsied lesions, and 18F-BMS-986229 uptake on PET imaging correlated with pathologic evaluation by the combined positive score (Spearman rank correlation coefficient, 0.64). Seventy-one percent of patients with 18F-BMS-986229 accumulation on PET imaging also had lesions without 18F-BMS-986229 uptake, highlighting the intrapatient heterogeneity of PD-L1 expression. Patients treated with frontline programmed death 1 inhibitors who had 18F-BMS-986229 accumulation in any lesions on PET imaging had longer progression-free survival than patients without tracer accumulation in any lesions (median progression-free survival, 28.4 vs. 9.9 mo), though the small sample size prevents any definitive conclusions. Conclusion: PD-L1 PET imaging was safe, feasible, and concordant with pathologic evaluation and offers a potential noninvasive tool to assess PD-L1 expression.

Top advances of the year: Ovarian cancer

Although cure rates remain low and effective screening strategies are elusive, the recent advances in systemic therapies over the past year highlighted in this review have prolonged survival for women with ovarian cancer. In 2022, the first antibody-drug conjugate for platinum-resistant ovarian cancer received accelerated US Food and Drug Administration (FDA) approval. Confirmatory studies examining the efficacy of mirvetuximab and other antibody-drug conjugates are underway. In the upfront setting, the first data establishing an overall survival benefit from poly(ADP-ribose) polymerase inhibitor maintenance was demonstrated after a 7-year follow-up period. In contrast, long-term updates from poly(ADP-ribose) polymerase inhibitor trials in the noncurative setting reported survival detriments, and the FDA withdrew the respective indications. Several trials attempted to improve upon the standard of care for platinum-sensitive ovarian carcinoma and those with rare ovarian cancer histologies (carcinosarcoma, clear cell carcinoma) but failed to demonstrate a clinically or statistically meaningful benefit. This leaves the open question of how to further optimize systemic therapy for advanced ovarian carcinoma to improve long-term survival and cure rates.

Clinical and molecular characteristics of early-onset vs average-onset esophagogastric cancer

BACKGROUND

The rate of esophagogastric cancer is rising among individuals under 50 years of age. It remains unknown whether early-onset esophagogastric cancer represents a unique entity. This study investigated the clinical and molecular characteristics of early-onset and average-onset esophagogastric cancer .

METHODS

We reviewed the Memorial Sloan Kettering Cancer Center gastric, esophageal, and gastroesophageal junction cancer database. Associations between baseline characteristics and tumor and germline molecular alterations were compared between those with early-onset and average-onset esophagogastric cancer using Fisher exact tests and the Benjamini-Hochberg method for multiple-hypothesis correction.

RESULTS

We included 1123 patients with early-onset esophagogastric cancer (n = 219; median age = 43 years [range = 18-49 years]) and average-onset esophagogastric cancer (n = 904; median age = 67 years [range = 50-94 years]) treated between 2005 and 2018. The early-onset group had more women (39% vs 28%, P = .002). Patients with early-onset esophagogastric cancer were more likely to have a gastric primary site (64% vs 44%, P < .0001). The signet ring cell and/or diffuse type was 3 times more common in the early-onset esophagogastric cancer group (31% vs 9%, P < .0001). Early-onsite tumors were more frequently genomically stable (31% vs 18%, P = .0002) and unlikely to be microsatellite instability high (2% vs 7%, P = .003). After restricting to adenocarcinoma and signet ring cell and/or diffuse type carcinomas, we observed no difference in stage (P = .40) or overall survival from stage IV diagnosis (median = 22.7 vs 22.1 months, P = .78).

CONCLUSIONS

Our study supported a preponderance of gastric primary disease sites, signet ring histology, and genomically stable molecular subtypes in early-onset esophagogastric cancer. Our findings highlight the need for further research to define the underlying pathogenesis and strategies for early detection and prevention.

Noninvasive Assessment of Human Epidermal Growth Factor Receptor 2 (HER2) in Esophagogastric Cancer Using 89Zr-Trastuzumab PET: A Pilot Study

Variations in human epidermal growth factor receptor 2 (HER2) expression between the primary tumor and metastases may contribute to drug resistance in HER2-positive (HER2+) metastatic esophagogastric cancer (mEGC). 89Zr-trastuzumab PET (HER2 PET) holds promise for noninvasive assessment of variations in HER2 expression and target engagement. The aim of this study was to describe HER2 PET findings in patients with mEGC. Methods: Patients with HER2+ mEGC were imaged with HER2 PET, 18F-FDG PET, and CT. Lesions were annotated using measurements (on CT) and maximum SUVs (on HER2 PET). Correlation of visualized disease burden among imaging modalities with clinical and pathologic characteristics was performed. Results: Thirty-three patients with HER2+ mEGC were imaged with HER2 PET and CT (12% esophageal, 64% gastroesophageal junction, and 24% gastric adenocarcinoma), 26 of whom were also imaged with 18F-FDG PET. More lesions were identified on 18F-FDG PET (median, 7 [range, 1-14]) than HER2 PET (median, 4 [range, 0-11]). Of the 8 lesions identified on HER2 but not on 18F-FDG PET, 3 (38%) were in bone and 1 was in the brain. Of the 68 lesions identified on 18F-FDG but not on HER2 PET, 4 (6%) were in bone and the remainder were in the lymph nodes (35, 51%) and liver (16, 24%). Of the 33 total patients, 23 (70%) were HER2 imaging-positive (≥50% of tumor load positive). Only 10 patients had 100% of the tumor load positive; 2 had 0% positive. When only patients receiving HER2-directed therapy as first-line treatment were considered (n = 13), median progression-free survival (PFS) therapy was not significantly different between HER2 imaging-positive and -negative patients. Median PFS for patients with at least 1 intense or very intense lesion (SUV ≥ 10) was 16 (95% CI: 11-not reached) mo (n = 7), compared with 12 (95% CI: 6.3-not reached) mo for patients without an intense or very intense lesion (n = 6) (P = 0.35). Conclusion: HER2 PET may identify heterogeneity of HER2 expression and allow assessment of lesions throughout the entire body. A potential application of HER2 PET is noninvasive evaluation of HER2 status including assessment of intrapatient disease heterogeneity not captured by standard imaging or single-site biopsies.

Abstract 5910: Prospective platform to define microbiome correlates of metastasis and therapy resistance in early onset and average onset gastrointestinal cancers

Background: The incidence of early onset (EO) gastrointestinal (GI) cancers prior to age 50 is rising, and the etiology is unknown. The gut microbiome may contribute to GI cancer pathogenesis, though how bacteria drive metastasis and treatment resistance is not known.

Purpose: To define the microbiome contribution to EO-GI cancers and metastasis by analyzing longitudinal samples from previously untreated patients with GI cancers.

Methods: We designed a prospective biospecimen collection platform. We selected patients with newly diagnosed, previously untreated colorectal cancer (CRC) and esophagogastric cancer (EGC). We collected stool, biopsy or surgical tissue, and peripheral blood mononuclear cells (PBMCs) at baseline prior to treatment and at each restaging scan for patients with metastatic disease. For those with locally advanced disease, we collected samples at baseline and after each treatment phase (surgery, radiation, chemotherapy). Stool samples were analyzed using shotgun sequencing. Tissue samples were banked for further analysis. Clinical data was manually curated. Relative abundances of bacteria at the species level were compared between groups. Alpha diversity was calculated using the inverse Simpson index and compared between groups using the Wilcoxon signed-rank test. Beta diversity was analyzed using the Bray-Curtis dissimilarity matrix and compared using PERMANOVA. Multivariate association between species abundance and clinical covariates was performed using MaAsLin2 R package.

Results: We analyzed a total of 150 stool samples from 76 patients (colorectal n=53, esophagogastric n=23), including up to 6 samples from a single patient over time. Mean alpha diversity did not differ significantly by primary site or age at diagnosis in patients with CRC but was higher in stage IV compared with stage I disease (P=0.054). Beta diversity was significantly different between samples from patients with right- compared with left-sided CRC (P=0.005) but did not differ significantly by diagnosis age (&lt;50 vs. &gt; 50). Among those with EGC, mean alpha diversity was not significantly different in samples from patients with esophagus or gastroesophageal junction (proximal) tumors compared with gastric (distal) tumors and did not differ significantly by age group. Beta diversity was significantly different between patients with EGC over 50 compared with those under 50 (P=0.002). When CRC baseline samples were examined, several bacterial species were associated with age &lt;50 at diagnosis, including Streptococcus anginosus group (P=0.001), Solobacterium moorei (P=0.013), and Firmicutes bacterium CAG83 (P=0.016).

Conclusions/Future Directions: Microbiome composition may cluster by primary tumor site and age at diagnosis in patients with previously untreated GI cancers. Functional analysis and is ongoing and will be presented.

Citation Format: Melissa A. Lumish, Asha R. Saxena, Nicholas Waters, Anqi Dai, Saskia Hartner, Teng Fei, Matthew Drescher, Jonathan Bermeo, Dorina Ismailgeci, Maggie Fox, Yelena Y. Janjigian, Luis A. Diaz, Martin R. Weiser, Jonathan Peled, Marcel van den Brink, Karuna Ganesh. Prospective platform to define microbiome correlates of metastasis and therapy resistance in early onset and average onset gastrointestinal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5910.

Practical Considerations in Diagnosing and Managing Early-Onset GI Cancers

The incidence of early-onset (EO) GI cancers occurring in individuals younger than age 50 years has been rising at an alarming rate over the past two decades. Although this rise in incidence among young patients correlates with increased rates of obesity, changes in diet, and alterations in the environment, the effects of these environmental factors on carcinogenesis, metastasis, and treatment response are unknown. Although several unique clinical trends exist among EO-GI cancers and their average-onset GI cancer counterparts, GI cancers are molecularly indistinct between younger and older patients, and no data support distinct treatment paradigms for patients with EO disease. The majority of EO-GI cancers are not explained by germline changes. There remains a critical need for further research to understand the pathogenesis and optimal management of EO-GI cancers. In addition, current screening strategies are not adequate to identify EO-GI cancers, and early biomarkers are needed. Specialized centers, with a focus on psychosocial aspects of cancer management, can address the unique care needs of patients with EO-GI cancers.

A Comprehensive Comparison of Early-Onset and Average-Onset Colorectal Cancers

BACKGROUND

The causative factors for the recent increase in early-onset colorectal cancer (EO-CRC) incidence are unknown. We sought to determine if early-onset disease is clinically or genomically distinct from average-onset colorectal cancer (AO-CRC).

METHODS

Clinical, histopathologic, and genomic characteristics of EO-CRC patients (2014-2019), divided into age 35 years and younger and 36-49 years at diagnosis, were compared with AO-CRC (50 years and older). Patients with mismatch repair deficient tumors, CRC-related hereditary syndromes, and inflammatory bowel disease were excluded from all but the germline analysis. All statistical tests were 2-sided.

RESULTS

In total, 759 patients with EO-CRC (35 years, n = 151; 36-49 years, n = 608) and AO-CRC (n = 687) were included. Left-sided tumors (35 years and younger = 80.8%; 36-49 years = 83.7%; AO = 63.9%; P < .001 for both comparisons), rectal bleeding (35 years and younger = 41.1%; 36-49 years = 41.0%; AO = 25.9%; P = .001 and P < .001, respectively), and abdominal pain (35 years and younger = 37.1%; 36-49 years = 34.0%; AO = 26.8%; P = .01 and P = .005, respectively) were more common in EO-CRC. Among microsatellite stable tumors, we found no differences in histopathologic tumor characteristics. Initially, differences in TP53 and Receptor Tyrosine Kinase signaling pathway (RTK-RAS)alterations were noted by age. However, on multivariate analysis including somatic gene analysis and tumor sidedness, no statistically significant differences at the gene or pathway level were demonstrated. Among advanced microsatellite stable CRCs, chemotherapy response and survival were equivalent by age cohorts. Pathogenic germline variants were identified in 23.3% of patients 35 years and younger vs 14.1% of AO-CRC (P = .01).

CONCLUSIONS

EO-CRCs are more commonly left-sided and present with rectal bleeding and abdominal pain but are otherwise clinically and genomically indistinguishable from AO-CRCs. Aggressive treatment regimens based solely on the age at CRC diagnosis are not warranted.

Abstract 611: Colibactin mutation signatures are associated with a distinct colorectal cancer clinicopathologic phenotype

PURPOSE: Alterations in the gut microbiome contribute to colorectal cancer (CRC) pathogenesis. The genotoxin colibactin, produced by pks+ E. coli, directly binds to DNA, leaving genetic scars at A-T rich motifs that can be identified by whole genome/exome sequencing (WGS/WES) as hexanucleotide mutation signatures SBS28 and SBS41. Here, we investigated whether MSK-IMPACT, a clinical targeted exon capture assay with lower genomic coverage (341-468 cancer associated exons), could be used to identify colibactin mutation signatures (CMS) and provide insight into associated clinicopathologic phenotypes.

METHODS: From an institutional pan-cancer cohort of 36,158 tumors assayed using MSK-IMPACT, we identified 11,864 samples (1,386 CRC) with at least 20 mutations and applied TempoSig, an algorithm which uses maximum likelihood-based extraction of mutational signature proportions. Tumors with at least 10% of all mutations attributed to SBS28/41 were deemed CMS+. Due to the association of POLE mutations and microsatellite instability with distinct phenotypes, we excluded these cases from our analysis.

RESULTS: Consistent with prior reports based on WGS/WES, our MSK-IMPACT TempoSig pipeline identified CMS positivity in multiple cancers, notably gastrointestinal (GI) and head and neck cancers. Ampullary tumors (25%) and GI neuroendocrine tumors (8%) had the highest SBS28 and SBS41 positivity respectively. Among microsatellite stable CRCs, we identified 52 patients with at least one sample positive for SBS28 (N=25) or SBS41 (N=27). Compared with CMS negative tumors, SBS28+ but not SBS41+ tumors had higher chromosomal instability as quantified by fraction of the genome altered by copy number alterations (SBS28+: 33.4% vs. SBS28-: 22.3%, P&lt;.01), lower tumor mutation burden (SBS28+: 7.9/Mb vs. SBS28-: 8.8/Mb, P=.011), and a trend toward younger median age at sampling (57 (IQR 46-66) vs. 61 (IQR 51-70), P=.095). SBS28+ tumors harbored more frequent mutations in DNA damage repair (DDR) genes ATR (7.1 vs. 0.5%, P=.02) and ATM (14.3 vs. 4.1%, P=.03). Overall survival from diagnosis was decreased in patients with SBS28+ compared with SBS41+ tumors (22.0 vs. 43.7 months, P&lt;.07), regardless of initial stage (P&lt;.01). Histopathology revealed increased TILs in 13% of evaluable SBS28+ and 7% of SBS41+ tumors, while RNA FISH using a probe targeting the clbP gene required for colibactin synthesis was negative in all CMS+ samples, suggesting that colibactin mutagenesis is an early event not requiring persistent pks+ E. coli colonization.

CONCLUSIONS: TempoSig enables rigorous identification of colibactin mutation signatures in clinically utilized MSK-IMPACT targeted exon datasets. SBS28+ CRCs are clinically distinct and associated with early onset, poor prognosis and DDR pathway alterations. In ongoing studies, we are investigating the therapeutic implications of these findings.

Citation Format: Melissa A. Lumish, Anisha Luthra, Simran Asawa, Francesco Cambuli, Mark Donoghue, Hyung Jun Woo, Andrea Cercek, Rona Yaeger, Jinru Shia, Francisco Sanchez-Vega, Karuna Ganesh. Colibactin mutation signatures are associated with a distinct colorectal cancer clinicopathologic phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 611.

Immunotherapy for the treatment of colorectal cancer

Immune checkpoint inhibition (ICI) has transformed the management of metastatic colorectal cancer (mCRC) with mismatch-repair deficiency (dMMR) and microsatellite instability (MSI-H), though this constitutes on average less than 5% of mCRC, and ICI is ineffective in preserved MMR/microsatellite stable disease (pMMR/MSS). Here we review the efficacy of ICI in dMMR/MSI-H mCRC, poor response to ICI in pMMR/MSS mCRC, role for ICI in locally advanced disease, biomarkers of response, novel immunotherapies, and future directions in targeting resistance mechanisms.

Preoperative cholangitis is an independent risk factor for mortality in patients after pancreatoduodenectomy for pancreatic cancer

OBJECTIVES

Preoperative biliary stenting is required for patients with obstructive jaundice from pancreatic adenocarcinoma who are receiving neoadjuvant chemotherapy. While in most patients this approach results in durable biliary drainage, some patients develop cholangitis during neoadjuvant treatment. Further, several studies have shown that preoperative cholangitis in patients with hepatobiliary malignancies can result in substantially unfavorable outcomes. The aim of this study was to evaluate the impact of preoperative cholangitis in patients who underwent pancreaticoduodenectomy after completing neoadjuvant chemotherapy.

METHODS

Participants: all adult patients (n = 449) diagnosed with pancreatic adenocarcinoma from January 1st, 2013 to March 31st, 2018 who pursued treatment at the Massachusetts General Hospital were screened. Of these 449 patients, 97 met final inclusion criteria of receiving neoadjuvant chemotherapy with intent to pursue curative surgery. Data were collected via retrospective chart review including baseline characteristics, survival, episodes of preoperative cholangitis, and surgical complications.

RESULTS

In patients completing successful pancreaticoduodenectomy surgery, preoperative cholangitis is associated with increased mortality (HR 2.67, 95% CI:1.16-6.13). This finding is independent of postoperative outcomes or tumor recurrence rate. The presence of cholangitis did not impact completion of neoadjuvant chemotherapy (92% vs 85%, p = 0.5) or ability to proceed to surgery (76% vs 75%, p = 1.0). Preoperative cholangitis was not associated with postoperative morbidity (42.1% vs 45.1%, p = 1.0).

CONCLUSIONS

One episode of cholangitis during neoadjuvant chemotherapy is associated with increased mortality following successful pancreaticoduodenectomy, independent of immediate postoperative outcomes or tumor recurrence. Preoperative cholangitis does not affect ability to pursue neoadjuvant chemotherapy or complete successful surgery. Patients who develop cholangitis during the neoadjuvant chemotherapy treatment phase may reflect a distinct phenotype of patients with PDAC with a complex and more challenging clinical course.

Cost-effectiveness and Budgetary Consequence Analysis of Durvalumab Consolidation Therapy vs No Consolidation Therapy After Chemoradiotherapy in Stage III Non-Small Cell Lung Cancer in the Context of the US Health Care System

Importance

In early 2018, durvalumab became the first immunotherapy to be approved for adjuvant treatment of patients with unresectable stage III non-small cell lung cancer (NSCLC) whose cancer has not progressed after definitive chemoradiotherapy. However, the cost-effectiveness and potential economic implications of using this high-priced therapy in this indication are unknown to date.

Objective

To explore the cost-effectiveness and potential budgetary consequences of durvalumab consolidation therapy vs no consolidation therapy after chemoradiotherapy in stage III NSCLC in the context of the US health care system.

Design, Setting, and Participants

A decision analytic microsimulation model was developed in an academic medical setting to compare the following 2 postchemoradiotherapy strategies: all patients receive no consolidation therapy until progression vs all patients receive durvalumab consolidation therapy until progression or for a maximum of 1 year. The potential budgetary consequence was calculated by applying the proportion of patients with NSCLC who were diagnosed in stage III and received chemoradiotherapy to the projected number of annual new cases for 2018 to 2022 to find total eligible patients and then multiplied by the mean difference in annual cost between the strategies over this 5-year period. Simulated conditions were matched to those of the PACIFIC phase 3 randomized clinical trial and reasonable treatment strategies for metastatic NSCLC. All simulated patients begin disease free after having received radical treatment with chemoradiotherapy and are followed up as they progress to metastatic disease first-line treatment, metastatic disease second-line treatment, end-stage progressive disease, and death.

Main Outcomes and Measures

The main outcome of this study was the incremental cost-effectiveness ratio of durvalumab consolidation therapy vs no consolidation therapy, given as aggregate cost of treatment per quality-adjusted life-year gained.

Results

Among 2 million simulated patients, durvalumab consolidation therapy was cost-effective compared with no consolidation therapy at a $100 000 per quality-adjusted life-year willingness-to-pay threshold, with an estimated incremental cost-effectiveness ratio of $67 421 per quality-adjusted life-year, and would contribute an additional $768 million to national cancer spending in year 1. The annual budgetary consequence would then decrease to $241 million in year 5.

Conclusions and Relevance

Durvalumab consolidation therapy represents an indication where expensive immunotherapies can be cost-effective. Treating with immunotherapy earlier in the course of cancer progression can provide significant value, despite having a substantial budgetary consequence.

Intestinal Blautia Is Associated with Reduced Death from Graft-versus-Host Disease

The relationship between intestinal microbiota composition and acute graft-versus-host disease (GVHD) after allogeneic blood/marrow transplantation (allo-BMT) is not well understood. Intestinal bacteria have long been thought to contribute to GVHD pathophysiology, but recent animal studies in nontransplant settings have found that anti-inflammatory effects are mediated by certain subpopulations of intestinal commensals. Hypothesizing that a more nuanced relationship may exist between the intestinal bacteria and GVHD, we evaluated the fecal bacterial composition of 64 patients 12 days after BMT. We found that increased bacterial diversity was associated with reduced GVHD-related mortality. Furthermore, harboring increased amounts of bacteria belonging to the genus Blautia was associated with reduced GVHD lethality in this cohort and was confirmed in another independent cohort of 51 patients from the same institution. Blautia abundance was also associated with improved overall survival. We evaluated the abundance of Blautia with respect to clinical factors and found that loss of Blautia was associated with treatment with antibiotics that inhibit anaerobic bacteria and receiving total parenteral nutrition for longer durations. We conclude that increased abundance of commensal bacteria belonging to the Blautia genus is associated with reduced lethal GVHD and improved overall survival.