A prodrug of an acyclic nucleoside phosphonate, with potential anti-viral and antineoplastic activities. Upon administration, acyclic nucleoside phosphonate prodrug ABI-1968 is taken up by viral-infected cells and converted to its active metabolite. The metabolite is incorporated into DNA chains by DNA polymerases, which results in the termination of DNA synthesis, inhibits viral replication and induces apoptosis and inhibits the proliferation of susceptible virally-infected tumor cells.