Sonaiya, Sneh

Atezolizumab-bevacizumab and durvalumab-tremelimumab have established immunotherapy as a first-line standard of care in advanced hepatocellular carcinoma (HCC). Yet, objective response rates (ORRs) remain confined to approximately 15-20%, and no validated predictive biomarker exists for patient selection. Unlike melanoma and lung cancer, conventional markers, including programmed death-ligand 1, microsatellite instability-high status, and tumor mutational burden, have not demonstrated reliable predictive value in HCC. Prior narrative reviews comprehensively catalogued the biomarker landscape through 2022 but predate a wave of clinically significant publications. This narrative review synthesizes evidence published between 2020 and 2026, with particular emphasis on 2023–2026 data, within a unified clinical framework not provided by prior reviews. We critically evaluate tissue-based biomarkers, including the AI-derived Atezolizumab-Bevacizumab Response Signature-Pathology model, spatial multiplex immunohistochemistry, and β-catenin mutational profiling; blood-based biomarkers encompassing circulating tumor DNA for minimal residual disease detection and peripheral immune phenotyping; and serum indices including the CRAFITY score and neutrophil-to-lymphocyte ratio. Hepatitis B virus etiology and non-alcoholic steatohepatitis are discussed as biological modifiers of biomarker performance. We propose an original biomarker-guided clinical algorithm, a comparative clinical readiness table, and a disease-continuum biomarker timeline as practical tools for clinicians and trialists. Prospective biomarker-enrichment trials represent the most critical next step toward clinical translation.

Antibody–drug conjugates (ADCs) are reshaping the therapeutic approach to advanced gastrointestinal cancers by integrating tumor-specific monoclonal antibodies with potent cytotoxic payloads to improve targeted tumor cell destruction while minimizing systemic exposure. Compared to traditional chemotherapy, trastuzumab deruxtecan has significantly improved objective response rates and overall survival in HER2-positive gastric and gastroesophageal junction tumors after trastuzumab-based therapy. This supports its role as an important second-line or later treatment option. The ongoing advancement of ADCs targeting CLDN18.2, TROP2, and CEACAM5 indicates that this therapeutic category will continue to expand across gastrointestinal neoplasms. Nonetheless, these advancements are accompanied by a specific and clinically significant toxicity profile. Hematologic suppression, gastrointestinal side effects, hepatotoxicity, and notably interstitial lung disease (ILD) are essential consequences that may need inpatient assessment and care. Interstitial lung disease (ILD), although uncommon, may be severe or lethal if not identified immediately and treated swiftly with medication cessation and corticosteroids. In hospitalized patients, distinguishing ADC-related toxicity from infection or disease progression is often difficult owing to overlapping clinical manifestations, requiring meticulous evaluation and interdisciplinary cooperation. As ADCs are integrated into earlier treatment lines and across a broader patient population, hospital systems must evolve to ensure prompt identification, consistent management protocols, and efficient collaboration between oncology and inpatient teams. This study analyzes the mechanisms, clinical effectiveness, and safety profile of ADCs in gastrointestinal oncology, pointing out the importance of institutional preparedness to safely incorporate these medicines into standard clinical practice. These features also align ADC therapy with personalized medicine by emphasizing biomarker-guided patient selection and individualized toxicity monitoring.