X0202 4 2008-05-27 0001301081 Pharmasset Inc VRUS 0001284621 OTTO MICHAEL 303A COLLEGE ROAD EAST PRINCETON NJ 08540 0 1 0 0 Chief Scientific Officer Common Stock 2008-05-27 4 M 0 3766 6.00 A 23266 D Common Stock 2008-05-27 4 M 0 77498 3.00 A 100761 D Common Stock 2008-05-27 4 S 0 74803 17.50 D 25961 D Common Stock 2008-05-27 4 S 0 500 17.51 D 25461 D Common Stock 2008-05-27 4 S 0 600 17.52 D 24861 D Common Stock 2008-05-27 4 S 0 500 17.53 D 24361 D Common Stock 2008-05-27 4 S 0 1000 17.54 D 23361 D Common Stock 2008-05-27 4 S 0 200 17.55 D 23161 D Common Stock 2008-05-27 4 S 0 100 17.56 D 23061 D Common Stock 2008-05-27 4 S 0 1100 17.57 D 21961 D Common Stock 2008-05-27 4 S 0 200 17.58 D 21761 D Common Stock 2008-05-27 4 S 0 100 17.59 D 21661 D Common Stock 2008-05-27 4 S 0 100 17.59 D 21661 D Common Stock 2008-05-27 4 S 0 100 17.63 D 21361 D Common Stock 2008-05-27 4 S 0 100 17.62 D 21461 D Common Stock 2008-05-27 4 S 0 1061 17.80 D 20300 D Common Stock 2008-05-27 4 S 0 100 17.81 D 20200 D Common Stock 2008-05-27 4 S 0 500 18.00 D 19700 D Common Stock 2008-05-27 4 S 0 100 18.06 D 19600 D Common Stock 2008-05-27 4 S 0 100 18.09 D 19500 D Stock Option (Right to Buy) 6.00 2008-05-27 4 M 0 3766 0 D 2010-09-11 Common Stock 3766 0 D Stock Option (Right to Buy) 3.00 2008-05-27 4 M 0 77498 0 D 2014-08-09 Common Stock 77498 5835 D The option was granted on September 12, 2000 and became fully vested on October 1, 2001. The option was granted on August 10, 2004 and became vested 25% on August 10, 1005 and 6.25%each quarter thereafter. All transaction described on this Form 4 are the result of standing instructions set forth in a Rule 10b5-1 plan previously established by Dr. Otto. Bryce A. Roberts, Attorney in Fact for Michael J. Otto 2008-05-29