Chang H. Ahn had already spent most of his career evaluating potential cancer treatments when his elder sister was diagnosed with the disease in 1993. Despite all the hours and days Ahn devoted to searching for a cure, he could not prevent stomach cancer from taking her life. She was 43 years old when she died.

"I was powerless or helpless. Although I was an oncologist for many years, there was nothing I could do for her," Ahn said. "I decided someday I would develop very important cancer drugs."

Ahn continued evaluating drug candidates for the Food and Drug Administration, but when a draft of the Human Genome Project was published in 2000, the wealth of new information sparked old passions for conducting his own research.

In May 2001, Ahn left the security of his government job and established Rexahn Corp. in Rockville. While venture funding was tapering off for most start-ups, Rexahn was able to raise $4.52 million from two Korean pharmaceutical companies.

Rexahn's research focuses on the signaling mechanism that tells cells to multiply and grow. The theory is that if the signal can be shut off, cancer cells will stop growing and eventually die. Early data suggest this could be applied to most types of solid tumors, Ahn said.

The company has four drug candidates, the first of which will be in clinical trials later this year. Rexahn also landed a licensing and development deal with Rexgene Biotech Co. of Korea, which infused the firm with $1.5 million in revenue, a rarity for young biotech firms.

Ahn is optimistic about the potential for Rexahn's drug candidates and believes that his decades of experience with regulatory agencies will allow him to shorten the process to four years, rather than the six to eight it normally takes to get a new drug to market.

Biotechnology is a risky industry with as much disappointment as success, but Ahn says his dedication to the venture is unwavering.

"So many lives may be extended or saved," he said. "I always remember my sister. . . . It's kind of an inspiration, keeps pushing me to develop new cancer drugs."

From left, Debananda Das of Tripos Inc. meets with Rexahn Corp. employees Dong Sun Park, Chief Financial Officer Tae Heum Jeong, chief executive and chairman Chang H. Ahn and director Young B. Lee.Chang H. Ahn and team leader Heejeong Yoon. Ahn says he takes inspiration from knowing "so many lives may be extended or saved."