Health Technology Assessment Reports for Non-Oncology Medications in Canada from 2018 to 2022: Methodological Critiques on Manufacturers' Submissions and a Comparison between Manufacturer and Canadian Agency for Drugs and Technologies in Health (CADTH) Analyses.

INTRODUCTION: Identifying key differences between manufacturers' submitted analysis and economic reanalysis by the Canadian Agency for Drugs and Technologies in Health (CADTH) is an important step toward understanding reimbursement recommendations. We compared economic values reported in manufacturers' analysis with the CADTH reanalysis and also assessed methodological critiques. METHODS: Two reviewers extracted data from the clinical and economic reports in publicly available CADTH reports from 2018 to 2022. We used the Wilcoxon rank-sum test to assess the difference between mean economic values, and the Chi-square test to assess the association between the CADTH critique final recommendations. RESULTS: Of the total submissions, 99.4% included effectiveness critiques, 88.8% included model structure critiques, 69.1% included utility score critiques, and 78.7% included cost critiques. The median incremental cost-utility ratio (ICUR) in the manufacturers' analyses was $138,658/quality-adjusted life-year (QALY), 2.5-fold lower than the CADTH's reanalysis at $380,251/QALY (p < 0.001). The median CADTH reanalysis for 3-year budget impact analysis (BIA) was $4,575,102, which was 27% higher than the manufacturers' submitted 3-year BIA (p < 0.001). CADTH requested a price reduction for 95% of all submissions, and the median price reduction request was 63.5%. In 2021 and 2022, the willingness-to-pay threshold identified in CADTH reports remained constant at $50,000 per QALY gained for all medications. CONCLUSION: There was high frequency of CADTH critiques on manufacturers' submissions in all four aspects of economic submissions: effectiveness, cost, utility score and structure. We observed a higher median incremental cost and lower median incremental QALYs in the CADTH reanalysis compared with the manufacturers' submissions. The resulting higher ICUR in the CADTH reanalysis often leads to a recommendation that the manufacturer needs to reduce its price. The 3-year budget impact was higher in the CADTH reanalyses compared with manufacturers' submissions.

Synthesis of site-specific Fab-drug conjugates using ADP-ribosyl cyclases.

Targeted delivery of small-molecule drugs via covalent attachments to monoclonal antibodies has proved successful in clinic. For this purpose, full-length antibodies are mainly used as drug-carrying vehicles. Despite their flexible conjugation sites and versatile biological activities, intact immunoglobulins with conjugated drugs, which feature relatively large molecular weights, tend to have restricted tissue distribution and penetration and low fractions of payloads. Linking small-molecule therapeutics to other formats of antibody may lead to conjugates with optimal properties. Here, we designed and synthesized ADP-ribosyl cyclase-enabled fragment antigen-binding (Fab) drug conjugates (ARC-FDCs) by utilizing CD38 catalytic activity. Through rapidly forming a stable covalent bond with a nicotinamide adenine dinucleotide (NAD+ )-based drug linker at its active site, CD38 genetically fused with Fab mediates robust site-specific drug conjugations via enzymatic reactions. Generated ARC-FDCs with defined drug-to-Fab ratios display potent and antigen-dependent cytotoxicity against breast cancer cells. This work demonstrates a new strategy for developing site-specific FDCs. It may be applicable to different antibody scaffolds for therapeutic conjugations, leading to novel targeted agents.