First Report of Endoxifen Treatment for 1 Year: A Case Report of Bipolar Disorder
Abstract
Bipolar disorder is a common chronic psychiatric condition, with treatment aimed at remission of symptoms and prevention of mood episodes. The pathophysiology of bipolar disorder I involves over expression of protein kinase C, which is thus considered a therapeutic target. Endoxifen, the metabolite of tamoxifen, has enhanced inhibitory action against protein kinase C, with a good safety profile. Endoxifen has shown promise in phase II and III clinical trials, with notable reduction in several symptom scale scores. This report describes the case of a woman with bipolar disorder diagnosed ten years prior, who was experiencing relapses. A change in medication to include endoxifen was effective. This is the first report of endoxifen use for duration of one year.
Keywords
Download Options
Introduction
Bipolar disorders are one of the most common psychiatric conditions, and are the seventeenth leading cause of disability across the world. The estimated lifetime prevalence of bipolar disorders is 2.4%.(1) A significant concern is the high mortality rate, with a quarter of patients attempting suicide.(2) The aim of treatment for acute manic episodes is symptom reduction and full remission, and that of acute depressive episodes is remission of symptoms and reduction of hypomanic and manic episodes. Maintenance treatment is aimed to prevent mood episodes.(3) Despite the extensive research and wide range of therapeutics, bipolar disorder remains undertreated.(2)
Bipolar disorder I is the manic-depressive type, associated with overexpression of protein kinase C (PKC). Endoxifen is a metabolite of tamoxifen with enhanced inhibitory action against PKC, being four times more potent than tamoxifen. The antimanic activity has been demonstrated in phase II and III trials, with promise for use as monotherapy.(4) In this report, we highlight the use of endoxifen for management of bipolar disorder, wherein it was used for the period of one year, making this the first report of its kind.
Conclusion
The management of bipolar disorder requires treating manic and depressive episodes, as well as maintenance therapy to ensure long-term therapy to mood stability. This case reports highlights the role of endoxifen, which is a novel PKC inhibitor with enhanced inhibitory effect, which is independent of metabolic enzymes, has few adverse effects, rapid action and improves manic symptoms in patients with bipolar disorder. The clinical data was supported by our observations of improved symptoms, with no major relapses noted for the period of one year. Improvement over YMRS, MADRS, BPRS and CGI BP were observed. The patient had good quality of life within a year of endoxifen treatment and started doing household chores unlike before, with improved SF36 score. Endoxifen has the potential to be an effective therapeutic for bipolar disorder, with potential for safe long-term use.