Background: Claudin 18.2 (CLDN18.2) is contained within normal gastric mucosa epithelial tight junctions; upon malignant transformation, CLDN18.2 epitopes become exposed. Zolbetuximab, a chimeric monoclonal antibody, mediates specific killing of CLDN18.2-positive cells through immune effector mechanisms. Patients and methods: The FAST study enrolled advanced gastric/gastro-oesophageal junction and oesophageal adenocarcinoma patients (aged 18 years) with moderate-to-strong CLDN18.2 expression in 40% tumour cells. Patients received first-line epirubicin þ oxaliplatin þ capecitabine (EOX, arm 1, n ¼ 84) every 3 weeks (Q3W), or zolbetuximab þ EOX (loading dose, 800 mg/m 2 then 600 mg/m 2 Q3W) (arm 2, n ¼ 77). Arm 3 (exploratory) was added after enrolment initiation (zolbetuximab þ EOX 1000 mg/m 2 Q3W, n ¼ 85). The primary endpoint was progression-free survival (PFS) and overall survival (OS) was a secondary endpoint. Results: In the overall population, both PFS [hazard ratio (HR) ¼ 0.44; 95% confidence interval (CI), 0.29-0.67; P < 0.0005] and OS (HR ¼ 0.55; 95% CI, 0.39-0.77; P < 0.0005) were significantly improved with zolbetuximab þ EOX (arm 2) compared with EOX alone (arm 1). This significant PFS benefit was retained in patients with moderate-tostrong CLDN18.2 expression in 70% of tumour cells (HR ¼ 0.38; 95% CI, 0.23-0.62; P < 0.0005). Significant improvement in PFS was also reported in the overall population of arm 3 versus arm 1 (HR ¼ 0.58; 95% CI, 0.39-0.85; P ¼ 0.0114) but not in high CLDN18.2-expressing patients; no significant improvement in OS was observed in either population. Most adverse events (AEs) related to zolbetuximab þ EOX (nausea, vomiting, neutropenia, anaemia) were grade 1-2. Grade 3 AEs showed no substantial increases overall (zolbetuximab þ EOX versus EOX alone). Conclusions: In advanced gastric/gastro-oesophageal junction and oesophageal adenocarcinoma patients expressing CLDN18.2, adding zolbetuximab to first-line EOX provided longer PFS and OS versus EOX alone. Zolbetuximab þ EOX was generally tolerated and AEs were manageable. Zolbetuximab 800/600 mg/m 2 is being evaluated in phase III studies based on clinical benefit observed in the overall population and in patients with moderate-to-strong CLDN18.2 expression in 70% of tumour cells.

To identify novel markers differentially expressed in ovarian cancer versus normal ovary, we hybridized microarrays with cDNAs derived from normal human ovaries and advanced stage ovarian carcinomas. This analysis revealed down-regulation of the caveolin-1 gene (CAV1) in ovarian carcinoma samples. Suppression of CAV1 in ovarian carcinomas was confirmed using a tumor tissue array consisting of 68 cDNA pools from different matched human tumor and normal tissues. Immunohistochemistry demonstrated expression of caveolin-1 in normal and benign ovarian epithelial cells, but loss of expression in serous ovarian carcinomas. In low-grade carcinomas, redistribution of caveolin-1 from a membrane-associated pattern observed in normal epithelium to a cytoplasmic localization pattern was observed. No expression of caveolin-1 was detectable in four of six ovarian carcinoma cell lines investigated. In SKOV-3 and ES-2 carcinoma cells, which express high levels of the caveolin-1 protein, phosphorylation of the 22-kd caveolin-1 isoform was detected. Inhibition of both DNA methylation and histone deacetylation using 5-aza-2'deoxycytidine and Trichostatin A, respectively, relieves down-regulation of caveolin-1 in OAW42 and OVCAR-3 cells which is in part mediated by direct regulation at the mRNA level. Expression of CAV1 in the ovarian carcinoma cell line OVCAR-3, resulted in suppression of tumor cell survival in vitro, suggesting that the CAV1 gene is likely to act as a tumor suppressor gene in human ovarian epithelium.

BackgroundClaudin 18.2 (CLDN18.2) is physiologically confined to gastric mucosa tight junctions; however, upon malignant transformation, perturbations in cell polarity lead to CLDN18.2 epitopes being exposed on the cancer cell surface. The first-in-class monoclonal antibody, zolbetuximab (formerly known as IMAB362), binds to CLDN18.2 and can induce immune-mediated lysis of CLDN18.2-positive cells.Patients and methodsPatients with advanced gastric, gastro-oesophageal junction (GEJ) or oesophageal adenocarcinomas with moderate-to-strong CLDN18.2 expression in ≥50% of tumour cells received zolbetuximab intravenously every 2 weeks for five planned infusions. At least three patients were enrolled in two sequential cohorts (cohort 1300 mg/m2; cohort 2600 mg/m2); additional patients were enrolled into a dose-expansion cohort (cohort 3600 mg/m2). The primary end point was the objective response rate [ORR: complete and partial response (PR)]; secondary end points included clinical benefit [ORR+stable disease (SD)], progression-free survival, safety/tolerability, and zolbetuximab pharmacokinetic profile.ResultsFrom September 2010 to September 2012, 54 patients were enrolled (cohort 1, n = 4; cohort 2, n = 6; cohort 3, n = 44). Three patients in cohort 1 and 25 patients in cohorts 2/3 received at least 5 infusions. Antitumour activity data were available for 43 patients, of whom 4 achieved PR (ORR 9%) and 6 (14%) had SD for a clinical benefit rate of 23%. In a subgroup of patients with moderate-to-high CLDN18.2 expression in ≥70% of tumour cells, ORR was 14% (n = 4/29). Treatment-related adverse events occurred in 81.5% (n = 44/54) patients; nausea (61%), vomiting (50%), and fatigue (22%) were the most frequent.ConclusionsZolbetuximab monotherapy was well tolerated and exhibited antitumour activity in patients with CLDN18.2-positive advanced gastric or GEJ adenocarcinomas, with response rates similar to those reported for single-agent targeted agents in gastric/GEJ cancer trials.ClinicalTrials.gov numberNCT01197885.

Caveolae are 50-to 100-nm -shaped invaginations of the plasma membrane that have been implicated in endocytosis and signal transduction.1 Caveolae membranes are enriched with specific lipids (glycosphingolipids, sphingomyelin, and cholesterol) and different lipidmodified signaling molecules.2 Caveolins, a family of highly conserved 20-to 25-kd integral membrane proteins, are the principal protein component of caveolae. Thus far the mammalian caveolin family consists of four proteins, caveolin-1[␣], -1[␤], -2, and -3 encoded by three genes. Caveolins-1 and -2 are co-expressed, whereas the expression of caveolin-3 is muscle-specific.