Conference: 2017 PH Professional Network Symposium
Release Date: 10.06.2017
Presentation Type: Abstracts
File Download: 2017 PHPN Abstract 1024
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Medications targeting the prostacyclin pathway in PAH (prostacyclin, prostacyclin analogues, and prostacyclin receptor agonist) are available in various delivery routes including oral, intravenous, subcutaneous (SQ), and inhaled. Transition between medications in this class may be indicated due to progression of PAH, side effects (SEs), and/or patient preference. The lack of established protocols guiding transition is problematic, especially in the absence of comparative pharmacokinetic data. We present here our experience with a single patient with scleroderma-related PAH transitioning from selexipag to subcutaneous treprostinil.
Our patient is a 69 y/o male with scleroderma-associated PAH treated with selexipag, tadalafil and sitaxsentan. Despite triple therapy for one year, his disease progressed as indicated by worsening symptoms and right heart catheterization findings. His maximum dose of selexipag achieved was 800 mcg twice daily with dose escalation limited by intolerable lower extremity (LE) pain. His weight on transition day was 73 kg.
We estimated the dose conversion of selexipag 200 mcg BID=treprostinil 10 ng/kg/min based on discussions with PAH providers with transition experience in the opposite direction (treprostinil to selexipag). Using this “best estimate” we calculated the treprostinil target dose at 40 ng/kg/min. Due to the severity of our patient’s SEs from the selexipag, we aired conservatively and modified the target dose to 20 ng/kg/min during hospitalization, with up-titration as an outpatient in the subsequent 2-4 weeks. The transition occurred in the intensive care unit to provide close monitoring.
The planned inpatient titration schedule is outlined in Table 1. Columns A and B. The actual titration schedule is columns C and D.
The planned schedule in columns A and B in table above was modified by early cessation of selexipag* after the 12-hour dose in response to the patient experiencing intense side effects of flushing and headache at 16 hours (columns C and D). The inpatient transition was complete at 36 hours and the patient was discharged to home at 48 hours. A dose increase to 22 ng/kg/min was attempted 3 days’ post discharge with de-escalation to 20 ng/kg/min due to intolerable LE pain despite best practice symptom management. He was readmitted for 24 hours at 5 days’ post hospitalization for evaluation and treatment of a greater than usual injection site reaction. The remodulin dose was decreased to 18 ng/kg/min at 4 weeks’ post discharge due to ongoing severe leg pain. The patient reports improved shortness of breath and exercise tolerance on 18 ng/kg/min compared to pre-transition.
This case is a successful transition from selexipag to subcutaneous treprostinil in 36 hours without apparent physiologically significant SEs. The estimated equivalent selexipag to treprostinil dose in our patient is 200 mcg BID=5 ng/kg/min.