Antonin Holy, a renowned Czech scientist whose research significantly contributed to the development of antiviral drugs, has died.

Prague's Institute of Organic Chemistry and Biochemistry, where Holy had been working since 1960, said he died on Monday after battling an unspecified long-term disease. He was 75.

Holy, a research professor of nucleic acid chemistry, helped discover substances that are part of such drugs as Viread and Vistide, which are used for treatment of HIV-infected patients, and Hepsera for treatment of hepatitis B.

Holy was born Sept. 1, 1936. in Prague and only retired a year ago.

His institute called his death Tuesday "an immense loss."