Rapid, sensitive and cost-effective determination of immune checkpoint inhibitor activity using a magnetic bead-based binding assay.

Immune checkpoint Inhibitors (ICIs) are effective immunno-therapeutic agents for cancer. Rapid and sensitive determination of the blocking activity of ICIs is important for ICIs development and immunological research. Among various immune checkpoint (IC) binding assays, cell-based binding assays are widely regarded, and the functional ELISA is a convenient alternative. However, these methodologies are limited by time-consuming preparation of cell lines stably expressing IC molecules, or long turnaround time with high cost. In this study, two magnetic bead based binding assays were developed to evaluate activity of ICIs, which was determined by a soluble ligand/bead immobilized receptor based binding assay (sL/bR binding assay) that assessed efficacy to block binding of one soluble IC ligand on its cognate receptor immobilized beads, or by a soluble receptor/bead immobilized ligand based binding assay (sR/bL binding assay) that assessed efficacy to block binding of soluble IC receptor on its cognate ligand immobilized beads. Half maximal inhibitory concentration (IC50) values of ICIs were calculated to determine ICIs activity. The sL/bR binding assay accurately determined the activity of two TIGIT blocking antibodies, since the relative blocking activity of two TIGIT antibodies determined by the sL/bR binding assay established in this study and that by the cell based binding assay were almost identical. In contrast, the sR/bL binding assay showed significantly improved sensitivity to determine activity of two PD-1 blocking antibodies than the sL/bR binding assay that was tested in this study and previous reports. Moreover, both amount of the used recombinant protein of ICI receptor/ligand and turnaround time of the two binding assays were more than 10 times less than those of the functional ELISA. These data indicate that the two magnetic bead based binding assays are sensitive, rapid and cost-effective methods to determine blocking activity of ICIs.

Validation of the sleep impact scale in patients with major depressive disorder and insomnia.

OBJECTIVES: Chronic insomnia and depression are often associated. Measuring the impact on quality of life associated with changes in sleep in co-treatment of insomnia and depression requires a valid and reliable patient reported outcome (PRO) instrument. This study aimed to assess the validity of the Sleep Impact Scale (SIS), a sleep-specific PRO instrument, in a population comorbid with Major Depressive Disorder (MDD) and insomnia to support its use in clinical or clinical trial applications. RESEARCH DESIGN AND METHODS: Data from 379 subjects enrolled in a 27 week US, multi-center, phase IV, randomized, double-blind, parallel group, placebo-controlled trial of zolpidem tartrate extended-release taken in combination with escitalopram vs. placebo combined with escitalopram were pooled across treatment groups. Results from multi-trait analyses, tests of internal consistency and test-retest reliability, concurrent validity, known-groups validity, responsiveness, and thresholds for minimal important difference (MID) were examined. RESULTS: Mean baseline scores on the SIS ranged from 22.85 (+/-13.41) on Satisfaction with Sleep to 43.49 (+/-21.12) on Mental Fatigue, reflecting impairments due to sleep problems. The SIS was found to be internally consistent (alpha > or = 0.70 for all domains) and have good construct validity. The item-domain correlations were > or = 0.52 with no instance of an item correlating more highly with a domain other than its own. There were some floor and no ceiling effects. The test-retest reliability of the SIS domains ranged between 0.68 and 0.83. Clinical validity assessed through known groups methods was supported. The SIS was responsive to changes on all domains. Preliminary estimates of minimum important difference (MID) were obtained to interpret changes in SIS domains. LIMITATIONS: Limitations include the need for further qualitative research on content validity and the lack of a patient global assessment of change. CONCLUSIONS: This study yielded adequate evidence of the validity of the SIS for use in clinical trials and research on MDD patients with comorbid insomnia.