Patients Report Effects of Tolvaptan on ADPKD

By Danielle Bradshaw from In The Cloud Copy

Researchers in Germany have gone on record saying that there is a concern with how well patients are able to tolerate the medication tolvaptan throughout their everyday lives due to concerns about V2R antagonist induced polyuria (excess urination). This brought up questions about how well people who take tolvaptan are able to deal with their bodies producing more urine, how much of the medication is needed to get the best effect out of it, and what impact it has on a patient’s daily life.

What is ADPKD?

ADPKD or autosomal dominant polycystic kidney disease is a genetic (inherited) disorder that involves cysts growing inside of a person’s kidneys. ADPKD varies from person to person, but the symptoms are typically detected around the ages of 30 to 40. This is a progressive disease, so the symptoms often worsen over time.

The most commonly experienced symptoms are the aforementioned kidney cysts, headaches, and pain in the sides and back. Some people also experience urinary tract infections, high blood pressure, and pancreatic cysts. ADPKD usually happens when the PKD1 and PKD2 genes experience mutations but can also occur when the GANAB and DNAJB11 genes change, although this is much less common. Kidney failure is a common issue brought about by ADPKD and it is the most often found kidney disorder that is passed down genetically.

About the Study

Mussa Keaei, Msc, and a team of researchers pooled together data from ADPKD patients with the intention of determining if tolvaptan should be taken in an annual dosage. The study’s results were given at a Kidney Week 2019’s poster session and was titled Using Tolvaptan for ADPKD: Feasibility and Patient-Reported Outcome in the Real-Life Setting.

A large part of the study was to have the study participants complete questionnaires to report outcomes – in other words, report the increase of urine volume and how much their quality of life was affected, how well they adhered to taking the medication, as well as report any complications that they may have experienced. Pain and quality of life measurements were gathered from each patient using what’s called the 12-item Short Form (or SF-12) Health Survey and the Halt Progression of Polycystic Kidney Disease or the HALT-PKD study pain questionnaire.

The Patients’ Reports

Although the study’s results were shared in 2019, the test itself began in the latter half of 2015. At that time, over 560 people participated in the test. Most of the patients saw an increase of urine that ranged from 5 to 75 liters and the observation was made that the biggest increase occurred when they began with the first dose.

From that point, any further increases in urine volume were minimal. The number of people that adhered to taking tolvaptan was about 80% or around 448 people. Those that stopped taking tolvaptan reported that they experienced symptoms connected to polyuria.

Most of the participants in the study didn’t find that tolvaptan therapy was a major issue but there were a few of them – two-thirds of the group – who found it necessary to make small adjustments to their daily lives.

65% percent of patients (364 participants) said that the higher urine volume was hardly an issue at all and about 23% (around 129) said that the higher urine volume was either occasionally or commonly a problem for them. More than 90% (over 500 patients) said that they would recommend tolvaptan as an effective therapy.

As far as adherence to taking the medication went, there weren’t many patients who said that they skipped a dose and when those few did skip a dose did so, it was because of reasons such as medical, professional, and leisure activities. All-in-all, the patients who took tolvaptan and those who didn’t had very few differences between them. There was no difference observed in patients before or after they began taking tolvaptan over time, either.

The Research Team’s Final Word

The researchers summarized by saying that their data showed that even though taking tolvaptan did increase the volume of urine, it wasn’t enough to majorly impact most of their lives in a negative way. Most didn’t need to make big changes to their everyday lives and only around 20% (112) found the polyuria a significant enough issue to quit the treatments.

The patients’ overall quality of life wasn’t largely affected and many of them would, in fact, recommend the therapy to others if it was suggested by their nephrologists. The researchers hope that their findings will help convince nephrologists in the future to use tolvaptan therapy for ADPKD and to offer patient counseling once the treatment had begun.

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