ABSTRACT
OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, safety, and place in therapy of a phenylalanine-metabolizing enzyme indicated to reduce blood phenylalanine concentrations, pegvaliase injection. DATA SOURCES: Searches of MEDLINE (1946-September 1, 2018) were conducted using the terms pegvaliase and phenylalanine ammonia lyase (PAL). Additional data were obtained from the prescribing information, the product dossier obtained from the manufacturer, and Clinicaltrials.gov. STUDY SELECTION AND DATA EXTRACTION: All English language articles related to pharmacology, pharmacokinetics, efficacy, or safety of the combination therapy in human subjects were reviewed. DATA SYNTHESIS: Pegvaliase is a pegylated PAL enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. Blood phenylalanine levels were reduced by approximately 50% to 70% in patients receiving therapeutic doses of pegvaliase. However, most patients experienced adverse events. CONCLUSIONS AND RELEVANCE: The mainstay of therapy in phenylketonuria (PKU) has historically consisted of dietary restriction of phenylalanine. Pegvaliase injection is the first Food and Drug Administration (FDA)-approved enzyme substitution therapy for patients with PKU. The therapy may be a viable option for patients with documented blood phenylalanine >600 µmol/L who have failed existing management strategies.
ABSTRACT
OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, safety, and place in therapy of the fixed-dose combination (FDC) product, QTERN (dapagliflozin/saxagliptin) tablets. DATA SOURCES: Searches of MEDLINE (1946 to July 1, 2017) were conducted using the keywords QTERN, saxagliptin, and dapagliflozin. Additional data were obtained from the prescribing information, the product dossier, and Clinicaltrials.gov . STUDY SELECTION AND DATA EXTRACTION: All English language articles related to pharmacology, pharmacokinetics, efficacy, or safety of the combination therapy in human subjects were reviewed. DATA SYNTHESIS: The pharmacokinetics of saxagliptin and dapagliflozin were not affected significantly when administered as an FDC product. Saxagliptin may suppress the increased secretion of glucagon associated with dapagliflozin. The combination dapagliflozin/saxagliptin has been studied as add-on therapy to metformin in patients with uncontrolled type 2 diabetes mellitus (T2DM). The difference in hemoglobin A1C (A1C) between saxagliptin + dapagliflozin + metformin (triple therapy) and saxagliptin + metformin was -0.59 (95% CI = -0.81 to -0.37, P < 0.0001), and the difference between triple therapy and dapagliflozin + metformin was -0.27 (95% CI = -0.48 to -0.05, P = 0.0166). The combination was well tolerated when added to metformin. CONCLUSION: QTERN (dapagliflozin/saxagliptin) tablets are a reasonable option for patients with T2DM not controlled on metformin, but cost, insurance coverage, and a lackluster reduction in A1C will likely limit its use until more data regarding its effects on complications of diabetes and cardiovascular outcomes become available.
