Withdrawal pain following patients discontinuing Trk inhibitors

This article aims to expand on the existing literature regarding the incidence of withdrawal pain following discontinuation of Trk inhibitors and to explore strategies that mitigate this withdrawal pain.

A retrospective observational study was conducted among patients who were at least 18 years-old or older and had documentation of starting larotrectinib or entrectinib at University of California, San Francisco (UCSF) between November 2018 and November 2022. Data were collected from electronic records and pharmacy databases and a total of 21 patients were identified in this study.

Of the 21 patients included in this study, five patients (24%) experienced pain during temporary or permanent discontinuation of Trk inhibitor with the onset of withdrawal pain ranging from a few hours to three days following discontinuation. Various strategies were implemented to manage this pain including restarting of Trk inhibitor, tapering of Trk inhibitor on discontinuation, minimizing dose interruptions and use of prescription pain medications.

This article illustrates the presence of withdrawal pain syndrome in patients stopping a Trk inhibitor treatment and highlight the need for patient education to avoid missing any doses and for development of a guideline for Trk inhibitor discontinuation.