Correction: Presentation at ECE

23 May 2022

Diurnal Group plc

("Diurnal" or the "Company")

Correction: Diurnal to present research into the treatment of congenital adrenal hyperplasia at 24th European Congress of Endocrinology meeting

The following amendments have been made to the RNS Reach announcement (RNS Number: 3508M) released at 07:00 on 23 May 2022 by the Company.

Findings in fertility in CAH patients on hydrocortisone modified-release hard capsules (MR-HC, Efmody®)

The release now also includes the date of preparation and corporate code.

All other details remain unchanged. The full amended text is shown below:

Diurnal Group plc

("Diurnal" or the "Company")

Diurnal to present research into the treatment of congenital adrenal hyperplasia at 24th European Congress of Endocrinology meeting

Diurnal Group plc (AIM: DNL), the specialty pharmaceutical company targeting patient needs in chronic endocrine (hormonal) diseases, will be presenting research findings on the treatment and management of congenital adrenal hyperplasia (CAH) at this year's European Congress of Endocrinology, which takes place 21-24 May 2022 in Milan, Italy.

Over the four-day meeting, the following topics will be presented:

· Findings in fertility in CAH patients on hydrocortisone modified-release hard capsules (MR-HC, Efmody®).

· Findings on control of CAH on MR-HC.

· The burden of illness associated with adolescent and adult CAH.

· Literature review on supraphysiological glucocorticoid dosing in CAH.

· MR-HC effects on mineralocorticoid requirements.

CAH occurs when the production of cortisol from the adrenal gland is limited due to a genetic deficiency. CAH is associated with over-production of male sex hormones resulting in ambiguous genitalia at birth, precocious sexual development, infertility in men and women, and increased mortality through adrenal crisis.

Around 450,000 people globally are estimated to be living with a CAH disorder yet there is no standard treatment. Instead, a variety of steroids are used but data shows around two thirds of people living with CAH still have problems with disease control[i].

"Diurnal is committed to supporting research into diseases of cortisol deficiency, and developing solutions to support patients with these life-long disorders," said Richard Bungay, Interim Chief Executive Officer of Diurnal. "The ECE meeting marks a significant opportunity to contribute to the discussion by the medical community of recent research and developments in an area which has historically had very few advances. The Diurnal team is excited to be part of this event as we continue to focus on progress in the treatment and management of diseases of cortisol deficiency."

Notes to Editors

About Diurnal Group plc

Diurnal Group plc is a European, UK-headquartered, specialty pharmaceutical company dedicated to developing hormone therapeutics to aid lifelong treatment for rare and chronic endocrine conditions, including congenital adrenal hyperplasia, adrenal insufficiency, hypogonadism and hypothyroidism. Its expertise and innovative research activities focus on circadian-based endocrinology to yield novel product candidates in the rare and chronic endocrine disease arena.

For further information about Diurnal, please visit www.diurnal.com