Analysis of 4616 clinical trial initial submissions received by the Medicines and Healthcare products Regulatory Agency between February 2019 and October 2023.

Aims: This study aimed to analyse clinical trial initial submissions received by the MHRA between February 2019 and October 2023.

Methods: Data on submissions were extracted from the clinical trials unit data bank. The primary end-point was the type of clinical trial initial submissions. Secondary end-points were sponsor types, participant demographics, healthy volunteers, health categories and studies involving first in human and advanced therapy medicinal products. The analysis used descriptive statistics for all categorical variables.

Results: MHRA received 4616 submissions. The highest percentage was in 2020 (22.8%) and the lowest in 2023 (17.2%). Phase 3 submissions were the highest (32.6%) and and phase 4 the lowest (5.2%). Commercial sponsors represented 85.1% of the total submissions. Both sexes were included in most trials (90%), while the number of submissions involving females only (3.7%) was lower than male only trials (6.1%). The elderly population was represented in 67.7% of trials with pregnant and breastfeeding women represented in 1.1% and 0.6% of trials, respectively. Breastfeeding women were not included in phase 1. Paediatric trials mostly involved adolescents. Healthy volunteers were included in 16.5% of the total submissions. The most common health category was cancer (29.4%), with the lowest being pain. First in human submissions represented 12.7% and advanced therapy medicinal products 3.4% of submissions.

Conclusions: These results highlight the clinical trial landscape in the United Kingdom and represent an important baseline for policymakers, healthcare providers, sponsors and patients and will enable an assessment of how policy changes can improve the variety and number of clinical trials.