The three primary endpoints measured through week 12 favored acetaminophen ER as follows : least squares ( LS ) mean change from baseline for WOMAC physical function subscale score was significantly greater for acetaminophen ER than for placebo ( P = 0.011 ) ; LS mean patient 's global assessment of response to therapy was significantly greater for acetaminophen ER than for placebo ( P = 0.010 ) ; and LS mean change from baseline for WOMAC pain subscale score was marginally greater for acetaminophen ER than for placebo ( P = 0.054 ) .