Myogen Inc. added $14 million to its previously announced $52.4 million private placement of Series D preferred stock, bringing the total to $66.4 million raised in this series.

Denver-based Myogen will use the money to support existing research and development programs focused on the heart.

Participants in the additional closing include the Perseus-Soros BioPharmaceutical Fund LP, of New York; China Development Industrial Bank, of Taiwan; Hunt Ventures, of Dallas; Silicon Valley Bank, of San Jose, Calif.; and affiliates of Tenex Medical Investors, of San Mateo, Calif.

In August, Myogen completed the initial financing of $52.4 million, which was led by JP Morgan Partners, of San Francisco. (See BioWorld Today, Aug. 28, 2001.)

“This gives us a good two-year supply of cash,” said William Freytag, president and CEO of Myogen, noting that its late-stage clinical trials will require considerably more money to support than they did at earlier stages, and it will allow Myogen to make “meaningful progress” in its clinical programs.

Since its first financing in October 1998, privately held Myogen has raised $90.4 million.

Freytag said this latest financing effort drew a great deal of interest.

“We’re a product-based, late-stage clinical trial development company, and I think that’s what in today’s market is most appealing,” Freytag said.

Myogen’s lead product is enoximone, which it acquired rights to from Hoeschst Marion Roussel AG, now Aventis SA, in 1998. Enoximone is a small organic molecule that increases the force of the heart’s contractions. Aventis developed an intravenous formulation, called Perfan IV, and an oral formulation. Perfan IV is approved in seven European countries and generates about $3 million in annual revenue. The oral formulation is in Phase III trials, which are scheduled for completion by year’s end. Closer to completion of these Phase III trials, Myogen expects to seek a partner for oral enoximone, which Freytag has estimated could bring in between $400 million and $500 million worldwide annually.

The IV formulation is given to severely ill patients to stabilize them, while the oral formulation would be administered in improving or less-ill patients. Myogen plans to launch the IV and oral formulations simultaneously in the U.S.

Myogen is about to begin Phase II trials of ambrisentan (BSF 208075), an endothelin receptor antagonist, which is believed to hold promise in the treatment of heart failure, chronic renal failure and pulmonary arterial hypertension by preventing the constriction of blood vessels and increasing blood flow to vital organs. The Phase II trials will be for all three indications.

Myogen entered a co-development and license agreement for ambrisentan with Knoll AG, of Ludwigschafen, Germany (now Abbott Laboratories, of Abbott Park, Ill.), in November 2000. However, a year later, Abbott gave exclusive worldwide rights to Myogen, which was to provide undisclosed up-front money and milestone payments, as well as royalties, to Abbott. (See BioWorld Today, Nov. 30, 2001.)

The company’s research efforts are focused on the discovery and development of drugs that could halt or reverse the progression of heart failure.