# The effects of Growth hormone treatment discontinuation in Adults on Metabolic profile, Body composition and quality Of Life (GAMBOL Study)

## TL;DR

This study explores whether stopping long-term growth hormone treatment in adults with growth hormone deficiency is feasible and acceptable, aiming to inform future clinical guidelines.

## Contribution

The study introduces a mixed-methods approach to assess the feasibility of a future randomized controlled trial on discontinuing growth hormone treatment in adults.

## Key findings

- An online survey will assess current clinical practices regarding GH treatment discontinuation in the UK.
- A feasibility cohort study will compare outcomes in patients discontinuing versus continuing GH treatment.
- Qualitative interviews will explore patient experiences and perceptions of participating in the study.

## Abstract

In adults, treatment of growth hormone deficiency with daily recombinant human growth hormone injections has shown to improve many clinical features associated with GHD. Currently, many adults with GHD receive GH treatment indefinitely. However, to date, no study has consistently demonstrated that GH treatment has a sustained beneficial effect in adults with GHD. A randomised controlled trial is needed to understand the impacts of discontinuation of long-term GH therapy in adults. However, prior to embarking on an RCT, the feasibility of a discontinuation study and the acceptability of randomisation to patients and clinicians need to be assessed.

(a) to explore the current practice of offering discontinuation of long-term GH treatment in adults in the UK and

(b) to assess the feasibility of conducting an RCT looking at the effects of discontinuing long-term GH treatment in adults with GHD

This mixed-method study which will be conducted in three phases.

Phase 1: An online survey of endocrine clinicians’ practice of offering discontinuation of long-term GH therapy in adult patients with GHD.

Phase 2: Feasibility cohort study which involves recruiting two groups of adult patients with GHD (aged more than 25 years), who have been on GH treatment for at least 5 years.: (a) an intervention group consisting of 20–25 patients who will be discontinuing their long-term GH treatment for two years and (b) a control group consisting of 20–25 patients who will continue with their GH treatment.

Phase 3: Qualitative study. 10–16 participants will be recruited to explore their experiences of participation in the feasibility study using semi-structured interviews.

This study will provide evidence of current GH treatment discontinuation practice in the UK and determine the feasibility of any future RCT. Long-term, this could promote and underpin the development of the much-needed relevant clinical guidance.

Growth hormone deficiency (GHD) is a condition that develops when the pituitary gland secretes less growth hormone (GH) than the body needs. In adults, GHD usually occurs when the pituitary gland becomes damaged by a tumour (growth), surgery and/or radiotherapy. Studies of short duration have shown that treatment with daily GH injections can improve the symptoms experienced by patients with GHD. In the UK, most adults with GHD are prescribed with GH indefinitely. However, some adult patients have questioned whether discontinuing their injections has any negative effects; currently, this is unclear. Hence, a systematic investigation examining the impact of discontinuing long-term GH treatment is urgently needed.

The aim of this is study to assess the feasibility of conducting a large-scale study to compare the effects of continuing and discontinuing long-term GH treatment in adult patients with GHD. This study will be conducted in three phases:
Phase 1: Online survey of endocrine specialists based in UK endocrine centres treating adult patients with GHD.Phase 2: Feasibility study involving two groups of adult patients with GHD who have been receiving GH treatment for at least 5 years. One group (intervention) will include 20–25 patients who are willing to stop taking GH treatment for two years. The second group (control) will include 20–25 patients who wish to continue GH treatment and are willing to undergo study monitoring for two years.Phase 3: Qualitative study involving face-to-face or telephone interviews of 10–16 patients to explore their experiences of participating, completing and/or withdrawing from the study.

Phase 1: Online survey of endocrine specialists based in UK endocrine centres treating adult patients with GHD.

Phase 2: Feasibility study involving two groups of adult patients with GHD who have been receiving GH treatment for at least 5 years. One group (intervention) will include 20–25 patients who are willing to stop taking GH treatment for two years. The second group (control) will include 20–25 patients who wish to continue GH treatment and are willing to undergo study monitoring for two years.

Phase 3: Qualitative study involving face-to-face or telephone interviews of 10–16 patients to explore their experiences of participating, completing and/or withdrawing from the study.

A patient and public advisory group has helped design this proposal and will be involved throughout the research project. The results of the study will be submitted for publication targeting leading endocrine journals will also be presented at local, national and international conferences and patient support group meeting.