Working hypotheses to solve the critical problems of the existing highly active anti-retroviral therapy were proposed. The study based on the hypotheses proved the validity of the hypotheses and resulted in the development of 2'-deoxy-4'-C-ethynyl-2-fluoroadenosine, a nucleoside reverse transcriptase inhibitor, with highly potent activity against all HIV-1, very favorable toxic profiles, and stability in plasma. The nucleoside will prevent or delay the emergence of drug-resistant HIV-1 variants and be an ideal therapeutic agent for both HIV-1 and HBV infections.