Relevant individual PK parameters will be estimated using non-compartmental PK methods. PK parameters will be compared when administered alone or in combination by a paired student's t-test. Comparison of PK parameters among dose levels will be performed using non-parametric statistical methods for K-independent samples. Associations between exposure parameters (Cmax and AUC) and pharmacodynamic endpoints (cellular PAR levels, mutation and/or altered expression of selected DNA repair genes) will be assessed using the appropriate non-parametric statistical tests.