The UK's Competition and Markets Authority (CMA) has now formally concluded that three pharmaceutical companies - Aspen, Tiofarma, and Amilco - took part in an illegal arrangement that inflated the price of life-saving medicine fludrocortisone.

The investigation has resulted in fines totalling almost £2.3 million and a payment of £8 million directly to the NHS (Aspen agreed to the latter last year, as previously reported).

The CMA concluded that Amilco and Tiofarma agreed to stay out of the market for fludrocortisone, a prescription-only medicine mainly used to treat primary or secondary adrenal insufficiency, commonly known as Addison’s Disease, so that Aspen could maintain its position as sole supplier in the UK.

In exchange, Amilco received a 30% share of the increased prices that Aspen was able to charge, and Tiofarma was given the right to be the sole manufacturer of the drug for direct sale in the UK.

Following the agreement, the price of fludrocortisone supplied to the NHS increased by up to 1,800%.

All three companies involved have now admitted to taking part in an anticompetitive agreement regarding the supply of fludrocortisone tablets, the CMA said.