compositions combinations kit of parts manufacture and or the use of the combinations according to this invention a compound of the formula i and the at least one compound of the formula ii which is preferably 3 u2032 deoxy 3 u2032 fluorothymidine or 3 u2032 deoxy 3 u2032 fluoro 5 o 2 l valyloxy propionyl guanosine or a pharmaceutically acceptable salt thereof are preferably present in a synergistic ratio usually this ratio is between about 1 250 to about 250 1 more preferably the ratio is between about 1 50 to about 50 1 the most preferred ratio is between about 1 20 to about 20 1 which includes the ratios 1 18 1 16 1 14 1 12 1 10 1 8 1 6 1 5 1 4 1 3 1 2 5 1 2 1 1 5 1 1 2 1 1 1 2 1 1 5 1 2 1 2 5 1 3 1 4 1 5 1 6 1 8 1 10 1 12 1 14 1 16 1 18 1 and all ranges in between if a further therapeutic agent is added ratios will be adjusted accordingly it will be appreciated that the amount of pharmaceutical composition according to the invention required for use in treatment or prophylaxis will vary not only with the particular compound selected but also.