Purpose: Zolbetuximab, an IgG1 monoclonal antibody, binds to claudin 18.2 (CLDN18.2) and mediates tumor cell death through antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. We sought to examine zolbetuximab combinations in CLDN18.2-positive HER2-negative gastric/gastroesophageal junction (G/GEJ) adenocarcinoma. Patients and Methods: This phase II study assessed efficacy and safety of zolbetuximab, alone or with modified FOLFOX6 (mFOLFOX6) or pembrolizumab, in CLDN18.2-positive advanced/metastatic G/GEJ adenocarcinoma. Patients received zolbetuximab as monotherapy in third/later-line (Cohort 1A, n = 30), with mFOLFOX6 in first-line (Cohort 2, n = 21), or with pembrolizumab in third/later-line (Cohort 3A, n = 3) treatment. The primary endpoint for Cohort 1A was objective response rate (ORR). Key secondary endpoints were ORR (Cohorts 2 and 3A), overall survival (OS; Cohort 1A), and progression-free survival (PFS) and safety (all cohorts). Results: ORR was 0% in Cohorts 1A and 3A, and 71.4% [95% confidence interval (CI), 47.82–88.72] in Cohort 2. Median PFS was 1.54 months (95% CI, 1.31–2.56) in Cohort 1A, 2.96 months (95% CI, 1.48–4.44) in Cohort 3A, and 17.8 months (95% CI, 8.05–25.69) in Cohort 2. Median OS in Cohort 1A was 5.62 months (95% CI, 2.27–11.53). Gastrointestinal adverse events occurred across cohorts [nausea, 63%–90% (grade ≥ 3, 4.8%–6.7%) and vomiting, 33%–67% (grade ≥ 3, 6.7%–9.5%)]. Conclusions: Zolbetuximab plus mFOLFOX6 demonstrated promising efficacy in previously untreated patients with CLDN18.2-positive G/GEJ adenocarcinoma. These data support the first-line development of zolbetuximab in patients whose tumors are CLDN18.2-positive. Across cohorts, zolbetuximab treatment was tolerable with no new safety signals.

PURPOSE: SHR-A1811 is an antibody-drug conjugate composed of an anti–human epidermal growth factor receptor 2 (HER2) antibody trastuzumab, a cleavable linker, and a topoisomerase I inhibitor payload. We assessed the safety, tolerability, antitumor activity, and pharmacokinetics of SHR-A1811 in heavily pretreated HER2-expressing or mutated advanced solid tumors. METHODS: This global, multi-center, first-in-human, phase I trial was conducted at 33 centers. Patients who had HER2-expressing or mutated unresectable, advanced, or metastatic solid tumors and were refractory or intolerant to standard therapies were enrolled. SHR-A1811 was administered intravenously at doses ranging from 1.0 to 8.0 mg/kg once every 3 weeks. The primary end points were dose-limiting toxicity, safety, and the recommended phase II dose. RESULTS: From September 7, 2020, to February 27, 2023, 307 patients who had undergone a median of three (IQR, 2-5) previous treatment regimens in the metastatic setting received SHR-A1811 treatment. As of data cutoff (February 28, 2023), one patient from the 6.4 mg/kg group experienced dose-limiting toxicities (pancytopenia and colitis). The most common grade 3 or higher adverse events (AEs) included decreased neutrophil count (119 [38.8%]) and decreased WBC count (70 [22.8%]). Interstitial lung disease occurred in only eight (2.6%) patients. Serious AEs and deaths occurred in 70 (22.8%) and 13 (4.2%) patients, respectively. SHR-A1811 led to objective responses in 59.9% (184/307) of all patients, 76.3% (90/118) of HER2-positive breast cancer, 60.4% (55/91) of HER2 low-expressing breast cancer, and 45.9% (39/85 with evaluable tumor responses) of the 98 nonbreast tumors. CONCLUSION: SHR-A1811 exhibited acceptable tolerability, promising antitumor activity, and a favorable pharmacokinetic profile in heavily pretreated advanced solid tumors. The recommended phase II dose of 4.8 or 6.4 mg/kg was selected for various tumor types.

Background: Nivolumab + chemotherapy is now a standard of care for HER2-negative, previously untreated, unresectable or recurrent gastric/gastroesophageal junction cancer (advanced gastric cancer), but long-term follow-up data of clinical trials are limited. Methods: ATTRACTON-4 was a phase 3, double-blind, placebo-controlled trial in Japan, South Korea, and Taiwan. Patients were randomized to either nivolumab or placebo, both combined with the physician’s choice of SOX (oral S-1 [tegafur–gimeracil–oteracil potassium] + oxaliplatin) or CAPOX (capecitabine + oxaliplatin). We report the primary endpoints—centrally assessed progression-free survival (PFS) and overall survival (OS)—and landmark analyses of OS among patients alive using 3-year follow-up data. Results: At the cutoff date (May 10, 2021), 17/359 patients in the nivolumab + chemotherapy group and 6/358 in the placebo + chemotherapy group were continuing study treatment. PFS (centrally assessed) was longer in the nivolumab + chemotherapy group (median 10.94 vs. 8.48 months; hazard ratio [HR] 0.67, 95% confidence interval [CI] 0.55–0.82). Although OS did not differ between the two groups (median 17.45 vs. 17.15 months; HR 0.89, 95% CI 0.75–1.05), the landmark analysis of OS, calculating HRs at each landmark time point (every month), was getting numerically better in the nivolumab + chemotherapy group over time. Approximately 80% of patients who achieved complete response in the nivolumab + chemotherapy group were alive at 3 years. No new safety signals or major late-onset select treatment-related adverse events were observed for nivolumab + chemotherapy. Conclusion: This 3-year follow-up of ATTRACTION-4 confirmed the long-term clinical benefit and manageable safety of nivolumab + chemotherapy in patients with previously untreated advanced gastric cancer. Trial registration: NCT02746796

PURPOSE: Treatment options for refractory advanced gastric and esophagogastric junction cancer (AGOC) are limited. Regorafenib, an oral multikinase inhibitor, prolonged progression-free survival (PFS) versus placebo in the INTEGRATE I phase II trial. INTEGRATE IIa was designed to examine whether regorafenib improved overall survival (OS). METHODS: A double-blind placebo-controlled phase III trial compared regorafenib and best supportive care (BSC) versus placebo and BSC for participants with confirmed evaluable metastatic/advanced AGOC who failed ≥two prior therapies on a 2:1 random assignment, stratified by tumor location, geographic region (Asia v rest of world), and prior vascular endothelial growth factor inhibitors. The primary end point was OS. Treatment efficacy on OS was first tested in the pooled INTEGRATE I + INTEGRATE IIa cohort and, if significant, then in the INTEGRATE IIa cohort. Secondary end points were PFS, objective response rate, safety, and quality of life (QoL). RESULTS: INTEGRATE IIa enrolled 251 participants: 157 from Asia and 94 from rest of world and 169 received regorafenib and 82 received placebo. No significant heterogeneity was observed between INTEGRATE I and INTEGRATE IIa studies on OS. Pooled OS analysis hazard ratio (HR) was 0.70 (95% CI, 0.56 to 0.87; P = .001; 361 events). INTEGRATE IIa alone OS HR was 0.68 (95% CI, 0.52 to 0.90; P = .006; 238 events), the median OS was 4.5 months versus 4.0 months, and 12-month survival rates were 19% and 6%, for regorafenib versus placebo, respectively. After a preplanned adjustment for multiplicity, there were no statistically significant differences across regions or other prespecified subgroups. Regorafenib improved PFS (HR, 0.53 [95% CI, 0.40 to 0.70]; P < .0001) and delayed deterioration in global QoL (HR, 0.68 [95% CI, 0.52 to 0.89]; P = .0043). The toxicity profile was consistent with that of previous reports. CONCLUSION: Regorafenib improves survival compared with placebo in refractory AGOC.

Epigenetic therapy has been demonstrated to be a viable strategy for breast cancer treatment. In this study, we report the anti-tumor activity of a hydroxamate-based histone deacetylase (HDAC)8-selective inhibitor, HMC, in breast cancer cells. MTT assays showed that HMC inhibited cell viability of MCF-7 and MDA-MB-231 cells with IC₅₀ values of 7.7 μM and 9.5 μM, respectively. HMC induced caspase-dependent apoptosis in MCF-7 cells, which was associated with its ability to modulate a series of cell survival-related signaling effectors, including Akt, mTOR, Bax, Mcl-1, and Bcl-2. Additionally, HMC was capable of activating PPARγ, which was accompanied by reduced expression of PPARγ target gene products, such as cyclin D1 and CDK6. HMC increased the production of ROS in MCF-7 cells, which could be partially reversed by the cotreatment with a ROS scavenger (N-acetylcysteine or glutathione). Furthermore, HMC induced autophagy, as characterized by the formation of acidic vesicular organelles and autophagic biomarkers including LC3B-II and Atg5. Notably, pharmacological blockade of autophagy by 3-MA or CQ could attenuate HMC-induced apoptosis, suggesting that autophagy played a self-protective role in HMC-induced cell death. Together, these data suggest the translational potential of HMC to be developed into a potential therapeutic agent for breast cancer therapy.