Immunotherapy (IO) agents have led to significant improvements in patient outcomes across many tumor types. There have been great efforts to introduce immune checkpoint inhibitors into the treatment paradigm of esophagogastric cancers as well. A number of randomized phase III trials, which will be reviewed here, established the role of these agents in both early-stage and advanced-stage disease. Adjuvant nivolumab is US Food and Drug Administration–approved after neoadjuvant chemoradiation and resection of esophageal and gastroesophageal junction cancers on the basis of the phase III CheckMate 577 trial. In the advanced setting, patients with programmed death receptor ligand-1–positive tumors should be recommended IO in combination with chemotherapy in the first-line setting on the basis of the results from KEYNOTE 590, CheckMate 649, and CheckMate 648. Across trials, chemotherapy continues to play a critical role in the first-line setting and should be offered to all patients who are eligible for systemic therapy, including those with biomarker select tumors. In the later lines of treatment, IO has modest activity, and prior studies have grown largely irrelevant because of the enrollment of IO-naive patients. Similar to other disease types, patients with microsatellite unstable (microsatellite instability high) tumors represent a unique cohort that is more sensitive to IO. However, there are no randomized studies evaluating how best to apply IO in early or advanced stages specifically for the treatment of patients with microsatellite instability high upper GI tumors. Questions remain how to best select patients who benefit from IO treatments, how to augment IO activity in programmed death receptor ligand-1–negative tumors, and how to incorporate IO in late-line settings or for recurrent disease that has been treated with IO-containing regimens during early stages.

Patient-derived cancer organoids (PDCOs) are organotypic 3D cultures grown from patient tumor samples. PDCOs provide an exciting opportunity to study drug response and heterogeneity within and between patients. This research can guide new drug development and inform clinical treatment planning. We review technologies to assess PDCO drug response and heterogeneity, discuss best practices for clinically relevant drug screens, and assert the importance of quantifying single-cell and organoid heterogeneity to characterize response. Autofluorescence imaging of PDCO growth and metabolic activity is highlighted as a compelling method to monitor single-cell and single-organoid response robustly and reproducibly. We also speculate on the future of PDCOs in clinical practice and drug discovery.Future development will require standardization of assessment methods for both morphology and function in PDCOs, increased throughput for new drug development, prospective validation with patient outcomes, and robust classification algorithms.

Purpose: Givastomig is a bispecific antibody that targets CLDN18.2 and conditionally activates local 4-1BB–expressing T cells. This first-in-human study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity of givastomig in advanced solid tumors. Patients and Methods: A total of 75 patients were enrolled. Escalating givastomig doses of 0.1 to 18 mg/kg were evaluated in 36 patients with metastatic or advanced solid tumors. An additional 6 patients per cohort with CLDN18.2-positive (defined as membrane intensity score of ≥1+ on ≥1% of tumor cells) advanced or metastatic gastric cancer, gastroesophageal junction cancer, or gastroesophageal carcinoma (GEC) were treated with 5 to 15 mg/kg givastomig across four cohorts. Fifteen patients with CLDN18.2-positive GEC were then enrolled to the 12 mg/kg dose expansion cohort. Results: No dose-limiting toxicities were reported up to 18 mg/kg, and a maximum tolerated dose was not reached. The most common treatment-related adverse events (in ≥10% of patients) were nausea, anemia, fatigue, white blood cell count decrease, vomiting, and increased alanine aminotransferase. Givastomig exposure increased dose proportionally, and soluble 4-1BB approached a plateau above 5 mg/kg. The 12 mg/kg dose was selected for dose expansion. A 16% objective response rate was observed in CLDN18.2-positive GEC above 5 mg/kg (N = 43). CLDN18.2 expression in responders ranged from 11% to 100%. Conclusions: Givastomig demonstrated manageable safety, dose-proportional exposure, and antitumor activity in patients with advanced solid tumors, particularly in CLDN18.2-positive GEC. A givastomig dose range of 5 to 12 mg/kg was chosen to combine with nivolumab and chemotherapy in part 2 of the study in frontline metastatic GEC. See related commentary by Pretelli and Garralda, p. 4866

Patient-derived cancer organoids (PDCO) are a valuable model to recapitulate human disease in culture, with important implications for drug development. However, current methods for rapidly and reproducibly assessing PDCOs are limited. Label-free imaging methods are a promising tool to measure organoid-level heterogeneity and rapidly screen drug responses in PDCOs. This study aimed to assess and predict PDCO response to treatments based on mutational profiles using label-free wide-field optical redox imaging (WF ORI). WF ORI provided organoid-level measurements of treatment response without labels or additional reagents by measuring the autofluorescence intensity of the metabolic coenzymes NAD(P)H and FAD, and the optical redox ratio, defined as the fluorescence intensity of [NAD(P)H/NAD(P)H + FAD], was used to measure the oxidation–reduction state of PDCOs. Development of leading-edge analysis tools helped maximize the sensitivity and reproducibility of treatment response measurements using WF ORI in colorectal cancer PDCOs. Leading-edge analysis improved sensitivity to redox changes in treated PDCOs. Additionally, WF ORI resolved FOLFOX (5-fluorouracil + oxaliplatin) treatment effects across all PDCOs better than two-photon ORI, with an approximately threefold increase in effect size. WF ORI distinguished metabolic differences based on driver mutations in colorectal cancer PDCOs, differentiating between KRAS + PIK3CA double-mutant PDCOs and wild-type PDCOs with 80% accuracy and identified treatment-resistant mutations in mixed PDCO cultures. Overall, WF ORI enables rapid, sensitive, and reproducible measurements of treatment response and heterogeneity in colorectal PDCOs that will affect patient management, clinical trials, and preclinical drug development. Significance: Label-free wide-field optical redox imaging is an accessible tool for monitoring changes in metabolism in patient-derived cancer organoids to reproducibly assess treatment response and heterogeneity in clinically relevant treatment studies.

Biliary tract cancer (BTC) is a rare and aggressive malignancy that is anatomically classified as gallbladder cancer (GBC), extra- and intra-hepatic cholangiocarcinoma (eCCA and iCCA) and ampullary cancer (AC). BTC is often diagnosed at an advanced stage when treatment options are limited and patients have a poor prognosis, so the identification of new drug targets is of critical importance. BTC is molecularly diverse and harbours different therapeutically actionable biomarkers, including mouse double minute 2 homolog (MDM2), which is currently being investigated as a drug target. The aim of this targeted review was to evaluate and synthesise evidence on the epidemiology of BTC and its subtypes in different geographic regions and on the frequency of MDM2 amplifications in BTC tumours. Epidemiological studies (N = 33) consistently demonstrated high incidence rates in South and Central Asia for BTC overall (up to 9.00/100,000) and for all subtypes, with much lower rates in Europe and the US. Among the different types of BTC, the highest global incidence was observed for CCA, mainly driven by iCCA (1.4/100,000), followed by GBC (1.2/100,000) and AC (0.18–0.93 per 100,000). Studies of MDM2 in BTC (N = 19) demonstrated variable frequency of MDM2 amplification according to subtype, with consistently high MDM2 amplification rates in GBC (up to 17.5%), and lower rates in CCA (up to 4.4%). The results from this literature review highlight the geographic heterogeneity of BTC and the need for standardised clinicopathologic assessment and reporting to allow cross-study comparisons.

Pancreatic and ampullary cancers remain highly morbid diseases for which accurate clinical predictions are needed for precise therapeutic predictions. Patient-derived cancer organoids have been widely adopted; however, prior work has focused on well-level therapeutic sensitivity. To characterize individual oligoclonal units of therapeutic response, we introduce a low-volume screening assay, including an automated alignment algorithm. The oligoclonal growth response was compared against validated markers of response, including well-level viability and markers of single-cell viability. Line-specific sensitivities were compared with clinical outcomes. Automated alignment algorithms were generated to match organoids across time using coordinates across a single projection of Z-stacked images. After screening for baseline size (50 μm) and circularity (>0.4), the match efficiency was found to be optimized by accepting the diffusion thresholded with the root mean standard deviation of 75 μm. Validated well-level viability showed a limited correlation with the mean organoid size (R = 0.408), and a normalized growth assayed by normalized changes in area (R = 0.474) and area (R = 0.486). Subclonal populations were defined by both residual growth and the failure to induce apoptosis and necrosis. For a culture with clinical resistance to gemcitabine and nab-paclitaxel, while a therapeutic challenge induced a robust effect in inhibiting cell growth (GΔ = 1.53), residual oligoclonal populations were able to limit the effect on the ability to induce apoptosis (GΔ = 0.52) and cell necrosis (GΔ = 1.07). Bioengineered approaches are feasible to capture oligoclonal heterogeneity in organotypic cultures, integrating ongoing efforts for utilizing organoids across cancer types as integral biomarkers and in novel therapeutic development.