Today I’ll be discussing the outlook for FTSE 100 pharmaceutical giants AstraZeneca, Shire and Hikma Pharmaceuticals. Shares in all three companies have outperformed the market since the vote to leave the EU, but are they likely to be sound investments in the longer term?

Brexit-resistant drugmaker

Anglo-Swedish drugs giant AstraZeneca (LSE: AZN) has won approval for a new antibiotic in the fight against drug resistance. The company was granted marketing authorisation by the European Commission for its Zavicefta treatment, a combination antibiotic developed in response to the increasingly urgent need for new drugs to treat serious infections that are becoming increasingly resistant to antibiotics.

Shares in the FTSE 100 stalwart have rallied over the past week or so, with impressive gains since the UK’s decision to leave the EU. But the market is expecting Astra to report a 14% dip in earnings for the full year to £3.4bn on significantly lower revenues, and I believe the shares look expensive at 17 times earnings. However, attractions remain for income-seekers with dividend payouts yielding well over 4% and covered almost one-and-a-half times by forecast earnings.

Unexpected boost

Dublin-based pharmaceuticals firm Shire (LSE: SHP) received an unexpected boost recently when a drug that had failed tests to treat a form of infant blindness instead showed positive effects on severe complications relating to lung and brain damage. The company hopes to start discussions with regulators about a phase-three clinical programme focusing on clinically relevant complications of prematurity later this year.

Like its larger rival AstraZeneca, Shire has outperformed the rest of the index since the vote to leave the EU, as investors have flocked to defensive sectors like pharmaceuticals and utilities. Analysts are talking about an impressive 77% rise in earnings this year, followed by a further 17% next year, leaving the shares trading on a reasonable P/E rating of 14 for 2017. I believe the shares still offer good value given the strong growth outlook.

Back to the big league

A welcome back to the FTSE 100 for Hikma Pharmaceuticals (LSE: HIK), which re-joined the top index recently after being relegated to the FTSE 250 in March following a share price slump at the start of the year. The drugmaker received a further boost recently after winning a court case dismissing claims of a patent infringement involving a rival’s gout treatment.

The son of the firm’s founder and current chief executive Said Darwazah celebrated the court case win by purchasing 150,000 shares worth £3.3m, along with two other directors who also bought 150,000 shares on the same day. Hikma’s shares have gained 21% in just three months and look to be trading at a premium 30 times forecast earnings for the year to December. I would put the stock on my watch list and wait for a better entry point before dipping into this quality pharmaceuticals play.

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Bilaal Mohamed has no position in any shares mentioned. The Motley Fool UK has recommended AstraZeneca and Hikma Pharmaceuticals. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.