Developing deprotectase biocatalysts for synthesis.

Organic synthesis often requires multiple steps where a functional group (FG) is concealed from reaction by a protecting group (PG). Common PGs include N-carbobenzyloxy (Cbz or Z) of amines and tert-butyloxycarbonyl (OtBu) of acids. An essential step is the removal of the PG, but this often requires excess reagents, extensive time and can have low % yield. An overarching goal of biocatalysis is to use "green" or "enzymatic" methods to catalyse chemical transformations. One under-utilised approach is the use of "deprotectase" biocatalysts to selectively remove PGs from various organic substrates. The advantage of this methodology is the exquisite selectivity of the biocatalyst to only act on its target, leaving other FGs and PGs untouched. A number of deprotectase biocatalysts have been reported but they are not commonly used in mainstream synthetic routes. This study describes the construction of a cascade to deprotect doubly-protected amino acids. The well known Bacillus BS2 esterase was used to remove the OtBu PG from various amino acid substrates. The more obscure Sphingomonas Cbz-ase (amidohydrolase) was screened with a range of N-Cbz-modified amino acid substrates. We then combined both the BS2 and Cbz-ase together for a 1 pot, 2 step deprotection of the model substrate CBz-L-Phe OtBu to produce the free L-Phe. We also provide some insight into the residues involved in substrate recognition and catalysis using docked ligands in the crystal structure of BS2. Similarly, a structural model of the Cbz-ase identifies a potential di-metal binding site and reveals conserved active site residues. This new biocatalytic cascade should be further explored for its application in chemical synthesis.

Evaluating the cost-effectiveness of voclosporin for the treatment of lupus nephritis in the United States.

BACKGROUND: Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus; up to 30% of patients with LN will develop end-stage kidney disease (ESKD). One of the main treatment goals for LN is preservation of kidney function, with early decreases in proteinuria associated with improved long-term outcomes. Voclosporin, a second-generation calcineurin inhibitor, was approved in the United States in 2021 for the treatment of active LN combined with background immunosuppression. The AURORA 1 study found that the use of voclosporin with low doses of mycophenolate mofetil and glucocorticoids yielded significant reductions in proteinuria. The AURORA 2 study showed long-term efficacy and safety of voclosporin over a 3-year period with kidney function preservation. The Institute for Clinical and Economic Review (ICER) is a nonprofit organization that evaluates medical evidence to help improve patient outcomes and control costs. In 2021, ICER published an economic model to estimate the impact and cost-effectiveness of LN therapies. From a US health care perspective, voclosporin was cost-effective at $149,260 per quality-adjusted life-year (QALY) and $131,528 per equal value of life-years gained (evLYG). At the time of the LN cost-effectiveness model (CEM) development, voclosporin was not yet approved in the United States and the cost of treating patients with LN with ESKD was not captured in the literature. OBJECTIVE: To evaluate the cost-effectiveness of voclosporin given the emergence of new data. METHODS: The LN CEM uses a short-term trial-based Markov model and long-term extrapolation using partitioned survival modeling data assuming adults with LN start with active disease, transitioning to complete or partial renal response, kidney failure, or death. In the current analysis, clinical data for voclosporin, duration of voclosporin treatment for nonresponders, and drug costs reflecting the 2023 price of voclosporin were updated. Additionally, health care payer costs of disease management were incorporated based on real-world claims data on the costs of treating patients with LN. RESULTS: Using the LN CEM with inputs reflecting the latest and most relevant evidence, the incremental cost of voclosporin per QALY was $88,076 and per evLYG was $77,643. For a subpopulation of Black, Hispanic, and Latino patients, the incremental cost of voclosporin per QALY was $77,435 and per evLYG was $67,828. CONCLUSIONS: Following the inclusion of updated data in the cost-effectiveness analysis, voclosporin remains a cost-effective therapy for the treatment of active LN including in a Black, Hispanic, and Latino subpopulation, substantially below the ICER willingness-to-pay threshold of $150,000/QALY.

Cochlear implant referral patterns in the UK suggest a postcode lottery with inequitable access for older adults; results of a pilot audit in five Audiology sites.

OBJECTIVE: To use a standardised reporting tool to identify potential eligible candidates for cochlear implant (CI) referral and quantify the proportion of adults who had a CI referral discussion after presenting with an audiogram within United Kingdom (UK) audiometric criteria. DESIGN: Retrospective multicentre 6-month audit of Audiology clinic databases. STUDY SAMPLE: A total of 810 adults from five geographically diverse UK Audiology sites. RESULTS: Data were collected in late 2019 after UK CI audiometric candidacy criteria changed; one site collected only 3 months of data. The proportion of potential eligible adults (based only on audiometry) considered for CI referral was 64% (521 out of 810) and varied by site (from 50% to 83%). About 24% of patients (123 out of 521) declined CI referral; this also varied across sites (12-45%). The median age of patients where CI referral was not considered was 80 years - significantly higher than the group where CI referral was considered (73 years). CONCLUSIONS: CI referral is dependent on where adults live, and how old they are. Older adults are significantly less likely to be considered for CI referral by Audiologists. Audiology clinics need more support to empower staff to talk to patients about CI referral.