Safety and efficacy of trastuzumab biosimilar plus irinotecan or gemcitabine in patients with previously treated HER2 (ERBB2)-positive non-breast/non-gastric solid tumors: a phase II basket trial with circulating tumor DNA analysis.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) (ERBB2)-directed agents are standard treatments for patients with HER2-positive breast and gastric cancer. Herein, we report the results of an open-label, single-center, phase II basket trial to investigate the efficacy and safety of trastuzumab biosimilar (Samfenet®) plus treatment of physician's choice for patients with previously treated HER2-positive advanced solid tumors, along with biomarker analysis employing circulating tumor DNA (ctDNA) sequencing. METHODS: Patients with HER2-positive unresectable or metastatic non-breast, non-gastric solid tumors who failed at least one prior treatment were included in this study conducted at Asan Medical Center, Seoul, Korea. Patients received trastuzumab combined with irinotecan or gemcitabine at the treating physicians' discretion. The primary endpoint was the objective response rate as per RECIST version 1.1. Plasma samples were collected at baseline and at the time of disease progression for ctDNA analysis. RESULTS: Twenty-three patients were screened from 31 December 2019 to 17 September 2021, and 20 were enrolled in this study. Their median age was 64 years (30-84 years), and 13 patients (65.0%) were male. The most common primary tumor was hepatobiliary cancer (seven patients, 35.0%), followed by colorectal cancer (six patients, 30.0%). Among 18 patients with an available response evaluation, the objective response rate was 11.1% (95% confidence interval 3.1% to 32.8%). ERBB2 amplification was detected from ctDNA analysis of baseline plasma samples in 85% of patients (n = 17), and the ERBB2 copy number from ctDNA analysis showed a significant correlation with the results from tissue sequencing. Among 16 patients with post-progression ctDNA analysis, 7 (43.8%) developed new alterations. None of the patients discontinued the study due to adverse events. CONCLUSIONS: Trastuzumab plus irinotecan or gemcitabine was safe and feasible for patients with previously treated HER2-positive advanced solid tumors with modest efficacy outcomes, and ctDNA analysis was useful for detecting HER2 amplification.

Microarrays for high-throughput genotyping of MICA alleles using allele-specific primer extension.

The role of major histocompatibility complex (MHC) class I chain-related gene A (MICA), a ligand of NKG2D, has been defined in human diseases by its allele associations with various autoimmune diseases, hematopoietic stem cell transplantation (HSCT) and cancer. This study describes a practical system to develop MICA genotyping by allele-specific primer extension (ASPE) on microarrays. From the results of 20 control primers, strict and reliable cut-off values of more than 30,000 mean fluorescence intensity (MFI) as positive and less than 3000 MFI as negative, were applied to select high-quality specific extension primers. Among 55 allele-specific primers, 44 primers could be initially selected as optimal primer. Through adjusting the length, six primers were improved. The other failed five primers were corrected by refractory modification. MICA genotypes by ASPE on microarrays showed the same results as those by nucleotide sequencing. On the basis of these results, ASPE on microarrays may provide high-throughput genotyping for MICA alleles for population studies, disease-gene associations and HSCT.

Distribution of the minor histocompatibility antigens in Korean population and disparities in unrelated hematopoietic SCT.

Minor histocompatibility antigens (mHags) are polymorphic peptides presented to T lymphocytes restricted by the MHC molecule. It has been reported that disparities of mHags are a potential risk factor for GVHD after hematopoietic SCT (HSCT). Here we observed allelic frequencies of HA-1, -2 and -8 in 139 Korean healthy individuals using PCR-sequence-specific primers, and analyzed the correlation between disparity of these mHags and acute GVHD (aGVHD) in 54 patients who underwent HSCT from unrelated HLA-identical donors. The allelic frequencies in Korean healthy individuals were 39.6 and 60.4% for HA-1(H) and HA-1(R), 92.4 and 7.6% for HA-2(M) and HA-2(V), 36.7 and 63.3% for HA-8(R) and HA-8(P), respectively. The frequencies of mHags incompatibility known to be associated with aGVHD were 16.7% in HA-1, 0% in HA-2 and 25.9% in HA-8. However, the statistically significant association of aGVHD with these mHags incompatibility was not found between healthy donors and leukemia patients after unrelated HSCT. This first report about mHags in Koreans may be helpful in further defining the clinical impact of mHags disparities in HSCT and in comparing with other populations.

Exposure to mixtures of solvents among paint workers and biochemical alterations of liver function.

The objective of this study was to determine biochemical alterations of liver function among paint manufacturers and sprayers associated with exposure to organic solvents. Two paint manufacturing factories and 22 various kinds of spray painting factories (16 car painting, two aircraft painting, three video terminal painting; and one trailer painting) were included. Air concentrations of organic solvents were collected by personal samplers and analysed by gas chromatography. A total of 180 workers were given a comprehensive physical examination, a questionnaire, a liver function test, and a test for hepatitis B surface antigen. The questionnaire contained questions regarding detailed personal medical history, intake of alcohol, and use of medicine. Mixtures of solvents were used throughout the factories, and xylene and toluene were the major components found in almost all air samples with average contents of 46% and 29% on a weight basis of 67 air samples. No strong hepatotoxic solvents were detected. Workers were classified according to the different exposure patterns and different air concentrations of breathing zones as: high (eight hour time weighted average (8 h TWA) hygienic effects of solvents 0.25-9.83, median 1.66), short term high (8 h TWA hygienic effects of solvents 0-3.38, median 0.12), and low (8 h TWA hygienic effects of solvents all below 0.38). After applying a multivariate model to control the non-occupational factors (alcohol, medication, age, and hepatitis B viral infection), increase in gamma-glutamyl transferase (GGT) activity was found to be associated with severity of exposure to the mixture of solvents. Because the possible effects on GGT activity of non-occupational factors were controlled for, it is concluded that increased GGT activity among exposed workers may be due to a higher exposure to the mixture of solvents.