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Case Reports in Endocrinology
Volume 2015, Article ID 952019, 3 pages
Case Report

Dipeptidyl Peptidase-4 Inhibition May Stimulate Progression of Carcinoid Tumor

1Internal Medicine Residency Program, Florida Hospital, 2501 N. Orange Avenue, Suite 235, Orlando, FL 32804, USA
2Cancer Institute of Florida, Florida Hospital, 2501 N. Orange Avenue, Suite 235, Orlando, FL 32804, USA

Received 24 May 2015; Accepted 21 July 2015

Academic Editor: Carlo Capella

Copyright © 2015 Vladimir Pech et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Dipeptidyl peptidase-4 (DPP-4) inhibitors, such as saxagliptin, have gained a rapid growth in use in the treatment of type 2 diabetes mellitus in the past decade. Although they are considered to have a good safety profile, controversy exists regarding their potential to stimulate neoplasm growth. We report here a patient with metastatic carcinoid tumor. His disease was stable for several years with plasma serotonin level (which was used to monitor disease progression) in 700–800 ng/mL range. After initiation of treatment with saxagliptin, however, his serotonin level almost doubled (1358 ng/mL), concerning progression of the disease. After discontinuation of saxagliptin, serotonin level returned to baseline quickly, while other laboratory markers, such as complete blood count (CBC), comprehensive metabolic profile (CMP) with liver function tests (LFTs), and lactate dehydrogenase (LD), remained unchanged before, during, and after the treatment with saxagliptin. This temporal correlation suggests a possible interaction between the activity of carcinoid tumors and the use of DPP-4 inhibitors. Although we were not able to find any literature providing a direct evidence that saxagliptin alters progression of the carcinoid tumors, we recommend alternative management for the treatment of diabetes in patients with carcinoid or other neuroendocrine tumors.