Pharmaceutical giant CSL has lifted first-half profit 6.8 per cent to $US1.16 billion ($A1.63 billion), helped by increased sales of its antibody replacement drugs in the US and its flu vaccines worldwide.

Sales revenue for the six months to December 31 rose 8.6 per cent to $US4.342 billion, and CSL raised its interim dividend by six US cents to 85 US cents ($A1.20).

Australia's fifth-largest listed company said it expects full-year profit to come in at the upper end of its existing guidance of $US1.88 billion to $US1.95 billion, on a constant currency basis.

"This is a solid result and particularly pleasing given it follows a very strong comparative period," chief executive and managing director Paul Perreault said.

"We are significantly improving the lives of patients around the world and that's why we're in business."

Sales of Haegarda, an injection that helps prevent the sudden swelling attacks caused by hereditary angioedema (HAE), have tripled, Mr Perreault said.

"It is changing people's lives."

Mr Perreault said CSL is a global leader in immunoglobulin (antibody) replacement therapy, with sales of drugs Privigen and Hizentra up by double digits after they were okayed to treat the debilitating neurological disorder CIDP.

Idelvion, an injection for patients with the blood clotting disorder haemophilia B, is also up 55 per cent, Mr Perreault said.

CSL's influenza vaccine business, Seqirus, delivered first-half earnings before interest and taxes of $US300 million, compared to a full-year loss of more than $US200 million three years ago, Mr Perreault said.

The company says Seqirus's Flucelvax flu shot has proven more effective than traditional influenza vaccines incubated in eggs, although due to the seasonality of the business Seqirus will likely post a loss for the second half of the year.

In December CSL opened a research centre in Melbourne, in conjunction with the University of Melbourne, that will provide space for 150 research scientists.

The company operates one of the world's largest blood plasma collection networks for its therapeutics derived from human plasma, but has had to increase its donor fees because of the better economic conditions there in the US.

Mr Perreault said Sequirus' president, Gordon Naylor, will retire later this year after a successful 31-year career at CSL, although he will stay on until his replacement is named.

At 1211 AEDT, CSL shares were down $A3.895, or 2.01 per cent, at $A189.795.

CSL'S FIRST-HALF PERFORMANCE

* Net profit up 6.8pct to $US1.16b

* Revenue up 8.6pct to $US4.5b

* Interim dividend up 6.0 US cents to 85 US cents