Measuring treatment impacts on symptoms in adults with hypoparathyroidism: findings from the PaTHway trial.

Background: Hypoparathyroidism is a rare endocrine disease frequently associated with serious physical and cognitive symptoms. This study's purpose was to understand the impacts of the phase 3 PaTHway clinical trial treatment, TransCon PTH, on patients' overall, physical, and cognitive hypoparathyroidism signs/symptoms and what patients consider meaningful improvement.

Methods: Individual telephone exit interviews were conducted with patients who recently completed the PaTHway trial blinded period. Using a semi-structured interview guide, interviews focused on trial treatment impact on hypoparathyroidism symptoms following the symptom list in the Hypoparathyroidism Patient Experience Scale-Symptom (HPES-Symptom). Meaningful changes in hypoparathyroidism symptoms were assessed with the Patient Global Impression of Severity (PGIS) and Patient Global Impression of Change (PGIC) measures. Interviewees were probed on the meaningfulness of reported changes in symptoms from prior to starting trial treatment to the past 2 weeks/current time. Interviews were audiotaped and transcribed. Transcripts were coded for emerging concepts and themes/subthemes covered in the interview guide based on an adapted grounded theory approach.

Results: Nineteen adults with hypoparathyroidism participated in interviews in the United States (n = 13, 68.4%) and Canada (n = 6, 31.6%). Marked improvements in physical and cognitive symptoms were described among trial treatment group respondents. The majority of participants who reported experiencing hypoparathyroidism physical symptoms pre-trial indicated symptom improvement with treatment, including muscle twitching (100%, n = 15), low energy (92.9%, n = 13), feeling tired (92.3%, n = 12), muscle weakness (92.9%, n = 13), tingling without numbness (84.6%, n = 11), trouble sleeping (92.3%, n = 12), muscle cramping (92.3%, n = 12), tingling with numbness (92.3%, n = 12), muscle spasms (100%, n = 12), and pain (90.9%, n = 10). Most participants who reported experiencing cognitive symptoms pre-trial reported symptom improvement with treatment, including difficulty finding the right words (86.7%, n = 13), difficulty concentrating (93.3%, n = 14), trouble remembering (92.9%, n = 13), trouble thinking clearly (85.7%, n = 12), and difficulty understanding information (83.3%, n = 10). Those in the placebo group reported limited or no improvement. The vast majority of participants affirmed that the improvements they experienced in symptom frequency on the PGIS/PGIC and HPES-Symptom were meaningful.

Conclusions: Findings indicate that TransCon PTH treatment improved participants' physical and cognitive hypoparathyroidism symptoms in meaningful ways, while reducing the daily burden associated with conventional therapy.

Trial registration: NCT04701203 Registered: 06 January 2021. https://clinicaltrials.gov/study/NCT04701203?term=NCT04701203&rank=1 .