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Correlation Between Urinary Fractionated Metanephrines in 24-hour and Spot Urine Samples for Evaluating the Therapeutic Effect of Metyrosine: A Subanalysis of a Multicenter, Open-Label Phase I/II Study

Correlation Between Urinary Fractionated Metanephrines in 24-hour and Spot Urine Samples for Evaluating the Therapeutic Effect of Metyrosine: A Subanalysis of a Multicenter, Open-Label Phase I/II Study

Kazuhiro Takekoshi, Fumitoshi Satoh, Akiyo Tanabe, Takahiro Okamoto, Atsuhiro Ichihara, Mika Tsuiki, Takuyuki Katabami, Masatoshi Nomura, Tomoaki Tanaka, Tadashi Matsuda, Tsuneo Imai, Masanobu Yamada, Suguru Asada, etc.

Endocr J. 2019 Dec 25;66(12):1063-1072.

PMID: 31511435

Abstract:

We recently conducted an open-label phase I/II study to evaluate the efficacy and safety of preoperative and chronic treatment with metyrosine (an inhibitor of catecholamine synthesis) in pheochromocytoma/paraganglioma (PPGL) in Japan. We compared creatinine-corrected metanephrine fractions in spot urine and 24-hour urine samples (the current standard for the screening and diagnosis of PPGLs) from 16 patients to assess the therapeutic effect of metyrosine. Percent changes from baseline in urinary metanephrine (uMN) or normetanephrine (uNMN) were compared between spot and 24-hour urine samples. Mean percent changes in uMN or uNMN in spot and 24-hour urine were -26.36% and -29.27%, respectively. The difference in the percent change from baseline between uMN or uNMN in spot and 24-hour urine was small (-2.90%). The correlation coefficient was 0.87 for percent changes from baseline between uMN or uNMN measured in spot and 24-hour urine. The area under the receiver operator characteristic (ROC) curve of uMN or uNMN measured in spot urine vs. 24-hour urine (reference standard) to assess the efficacy of metyrosine treatment was 0.93. Correlations and ROCs between 24-hour urinary vanillylmandelic acid, adrenaline, and noradrenaline and 24-hour uMN or uNMN were similar to those between spot uMN or uNMN and 24-hour uMN or uNMN. No large difference was observed between spot and 24-hour urine for the assessment of metyrosine treatment by quantifying uMN or uNMN in Japanese patients with PPGLs. These results suggest that spot urine samples may be useful in assessing the therapeutic effect of metyrosine.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP672877-A	Metyrosine		672-87-7	Price

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