ZURICH (Reuters) - Swiss drug company Actelion expects an average annual per-patient price for its new pulmonary arterial hypertension medicine in the United States of $160,000 to $170,000, before rebates, Chief Operating Officer Otto Schwarz told analysts on Tuesday.

The drug, Uptravi, won approval from the U.S. Food and Drug Administration last month and went on sale this week, giving doctors another option to treat the deadly disease that kills victims within a few years.

Actelion declined to give forecasts for Uptravi's average price after rebates or say how many patients could be eligible annually for the treatment to open pulmonary arteries, easing pressure on the heart.

However, Schwarz said Uptravi will likely compete for treating a group of intermediate-stage disease sufferers who number around 3,800 people in the United States and now get inhaled treatments.

"There is an influx of new patients in this segment," Schwarz said, predicting physicians will prescribe Uptravi for them before progressing to an inhaled treatment.

Analysts have said Uptravi could reap more than $1 billion in global sales annually at its peak.

Even at $160,000 to $170,000 Schwarz said Uptravi is priced more cheaply than other inhalable pulmonary arterial hypertension treatments including United Therapeutics's Tyvaso and, consequently, unlikely to spawn significant payer resistance.

"Uptravi is priced - and this is why I think it is responsible pricing - below all inhaled prostacyclin therapies currently on the market," Schwarz said.

Chief Executive Officer Jean-Paul Clozel, on the same call, said the addition of Uptravi to Actelion's stable of drugs following the 2015 patent expiry of its blockbuster Tracleer drug will be sufficient to fund expansion for the next decade, including into new treatment areas.

"The revenues generated will enable us to fuel our research and development efforts outside the pulmonary arterial hypertension franchise and to transform our company," he said.

Clozell is counting on internal growth after being beaten out last year by AstraZeneca on the purchase of U.S biotech company ZS Pharma for $2.7 billion.

Suitable merger targets are rare, he said, especially if it must compete with larger companies with "deeper pockets."

"We have to count on our ability to discover for ourselves or licensing products," Clozell said. "But for M&A, I'm not very optimistic that we can find large, very good deals."

Actelion shares last traded up 1.68 percent at 139 francs, giving it a market value of 15.6 billion Swiss francs ($15.42 billion), about a quarter of the value of AstraZeneca's stock.

(Editing by Michael Shields, Greg Mahlich)