Assessment of Safety and Efficacy of Implantable Pump (LenusPro) in Patients With Pulmonary Arterial Hypertension Treated With Treprostinil.

Treprostinil is a prostacyclin analogue, a drug that is widely used to treat pulmonary arterial hypertension (PAH). Its efficacy was confirmed in studies that compared it to placebo and to epoprostenol. Due to stability of treprostinil sodium solution and its relatively long (when compared to prostacyclin) half-life, the drug enabled PAH patients to receive safe long-term treatment. It is administered as a continuous subcutaneous infusion using an insulin pump. In the case of this route of administration, its half-life is about 3 hours. Unfortunately, due to reaction at the infusion site many patients report significant deterioration of quality of life, and some of them (about 5-10%) even abandon treatment . There are trials in progress to find a more convenient method of administration for this drug. The efficacy of oral administration has been uncertain - reports are contradictory, while inhalations remain a valid alternative for patients in a less advanced stage of the disease. Therefore, for patients whose illness is more severe, only continuous parenteral administration of the drug remains an option.

The Lenus Pro® implantable pump appears to be a promising alternative to an external pump. By means of this method, treprostinil sodium is administered as a continuous intravenous infusion, and the drug reservoir is refilled every 28 days. Thermal stability of treprostinil at body temperature was confirmed during a 60-day observation; concentrations of the drug administered intravenously are comparable to subcutaneous administration, and the only differing parameter is a shorter half-life of less than 1 hour. The first experiences with implantable pumps originate in Austria and Germany and present this method of treatment as a milestone in PAH therapy. In Poland, the first implantation of a Lenus Pro® pump took place in 2013 (18).

The aim of this study is an analysis of efficacy and safety of treatment with intravenous treprostinil administered by means of the Lenus Pro® implantable pump.

Prior to pump implantation the subcutaneous dose of treprostinil is escalated up to the highest dose tolerated by a particular patient. The procedure of pump implantation is carried out under general anaesthesia Clinical and haemodynamic evaluation is performed at the time of initiating PAH therapy with treprostinil. Right before and during 2-9 months after Lenus Pro® pump implantation, non-invasive clinical evaluation was made, including: WHO functional class, 6-minute walking test (6MWT), and concentration of NT-proBNP. Additionally patients fill in the SF36 quality of life questionnaire before implantation and 2-9 months after implantation.