LOS ANGELES, April 24 (Reuters) - The swine flu outbreak is likely to benefit one of the most prolific and successful venture capital firms in the United States: Kleiner Perkins Caufield & Byers, Thomson Reuters Private Equity Week reported on Friday.

Shares of the two public companies in the firm's portfolio of eight Pandemic and Bio Defense companies -- BioCryst Pharmaceuticals BCRX.O and Novavax NVAX.O -- jumped Friday on news that the swine flu killed a reported 60 people in Mexico and has infected people in the United States.

The World Health Organization said the virus appears to be susceptible to Roche's ROG.VX flu drug Tamiflu, also known as oseltamivir, but not to older flu drugs such as amantadine.

Shares of Swiss drugmaker Roche Holding AG closed up 3.48 percent after falling sharply earlier in the week on a cancer drug disappointment, while shares of U.S. biotechnology company Gilead Sciences Inc GILD.O, which gets royalties from Roche on Tamiflu sales, slipped 10 cents to $45.80 on Friday.

But BioCryst, a maker of drugs that block key enzymes in viral diseases, jumped more than 26 percent on Friday to $2.21 per share. Viral vaccine maker Novavax rose more than 75 percent to $1.42 per share.

BioCryst CEO John Stonehouse said his company does not anticipate the use of its technology in treating this episode of swine flu.

“We’re in clinical trials right now and not on the market,” Stonehouse said.

Still, the companies will have to go even higher for Kleiner Perkins to make its investment back. Both BioCryst and Novavax experienced long drops from price peaks in 2006, when reports of avian flu dominated headlines.

BioCryst is down nearly 90 percent from its 2006 high of $20.75 per share and Novavax is down more than 85 percent from a high of $7.98 per share.

Kleiner Perkins invested $30 million in BioCryst in December 2005 alongside Fort Worth, Texas-based buyout firm TPG. The two firms invested again in August 2007, picking up $65 million worth of shares and warrants. The investors bought shares in BioCryst at $13.46 and then $7.80.

Kleiner Perkins put $20 million in Novavax in February 2006 alongside Palo Alto, Calif.-based Prospect Venture Partners. The two firms picked up the shares at $4.35.

Novavax can produce a vaccine from an emergent strain of flu virus in 12 weeks, according to CEO Rahul Singhvi. The company has contacted the U.S. Centers for Disease Control and Prevention to offer help and is trying to contact the Ministry of Health in Mexico, Singhvi said.

The company uses genetic information and “recombinant, virus-like particle technology” to rapidly engineer a vaccine. Its technology has been proven to work in humans during Phase II trials, Singhvi said, and it might be used in the case of an emergency.

“There is an emergency authorization avenue that is available that would allow us to use the vaccine in an emergency without further testing,” said Singhvi.

Kleiner Perkins typically only invests in early stage start-up technologies. It is best known for its investments in Netscape, Amazon.com AMZN.O, Google GOOG.O and Genentech ROG.VX.

The Menlo Park, California-based VC firm launched a $200 million Pandemic Bio Defense fund in 2006 to invest in technology companies working on drugs, diagnostics and inoculations against flu-like diseases.

“We will invest to accelerate innovation, and we’re in a hurry,” Investor John Doerr said at the time. “We hope even a mild pandemic never recurs.”

Investors at Kleiner Perkins were not immediately available for comment.

The firm’s other Pandemic Bio Defense investments include: * San Francisco-based Anza Therapeutics, which is working on therapeutic vaccines for treating certain types of cancer and hepatitis C. * Fremont, Calif.-based Breathe Technologies, which is working on lightweight respiratory ventilator systems. * Emeryville, Calif.-based HX Diagnostics, which is working to make diagnostic tools for seasonal and emerging diseases. * Pleasanton, Calif.-based Juvaris BioTherapeutics Inc., which is working on vaccines and immunotherapeutics to treat infectious disease and cancer. * San Diego-based Trius Therapeutics, which is developing drugs to fight resistant-strains of bacteria. * Marlborough, Mass.-based Xcellerex Inc., which has developed tools and manufacturing processes to speed the deployment of new vaccines.