UK stocks decline as AstraZeneca tumbles after trial setback

The UK's FTSE 100 declined on Thursday as investors assessed renewed tensions in the Middle East, while pharmaceutical heavyweight AstraZeneca weighed heavily on the benchmark after reporting disappointing results from a late-stage clinical trial.

The blue-chip FTSE 100 index fell 0.6% to 10,417.63 points by 10:45 GMT.

In contrast, the domestically focused FTSE 250 index edged 0.1% higher, reflecting a mixed performance across the broader UK equity market.

Geopolitical tensions keep investors cautious

Investor sentiment remained subdued following fresh US strikes on Iran, which kept attention firmly on developments in the Middle East.

Oil prices edged slightly higher after the strikes.

However, concerns over a broader escalation eased after US President Donald Trump said he did not expect the conflict to develop into a full-scale war.

Despite the modest rise in crude prices, energy stocks fell 1%, making the sector one of the weaker performers during the session.

Market participants continued to monitor geopolitical developments for their potential impact on inflation and the outlook for interest rates.

AstraZeneca leads the pharmaceutical sector lower

Pharmaceutical stocks posted the steepest sectoral decline, falling 6.2%, largely due to sharp losses in AstraZeneca.

Shares of AstraZeneca dropped 9.2% after the company said its nerve disease drug Wainua, developed in partnership with US-based Ionis, failed to achieve the primary objective in a late-stage clinical trial.

The trial did not meet its main goal of reducing cardiovascular deaths and recurring heart-related problems, prompting investors to sell the stock and dragging the broader pharmaceutical sector lower.

Gold miners benefit from higher bullion prices

While most sectors struggled, precious metal miners outperformed the market.

The sector gained 2.6% as gold prices advanced, supported by a weaker US dollar that increased the appeal of bullion.

Investors also continued to seek safe-haven assets while monitoring geopolitical developments in the Middle East.

The gains in precious metal mining stocks partially offset weakness seen elsewhere in the market.

Playtech surges on strong earnings outlook

Among mid-cap stocks, Playtech emerged as the strongest performer.

Shares in the gaming company jumped 17.7% after it forecast adjusted core profit for 2026 above market expectations.

The company attributed its upbeat outlook to robust business growth across the United States and Latin America, encouraging investors and lifting the stock to the top of the FTSE 250 index.

Computacenter climbs on AI infrastructure demand

Computacenter was also among the day's standout performers on the FTSE 100.

The IT services provider rose more than 7% after saying it expects its annual results to exceed market expectations.

The company said stronger demand for AI-related infrastructure from hyperscale customers in North America and the UK supported its improved outlook.

The update reinforced investor confidence in continued enterprise spending on artificial intelligence infrastructure, helping Computacenter outperform the broader market even as the FTSE 100 remained under pressure from geopolitical uncertainty and weakness in the pharmaceutical sector.