12. Women of childbearing potential must have a negative serum or urine pregnancy test with a sensitivity of at least 50 mIU/mL 10 - 14 days prior to therapy and repeated within 24 hours of starting study drug and must either commit to continued abstinence from heterosexual intercourse or agree to use 2 contraceptive methods. These birth control methods must be used for at least 4 weeks before, during and after lenalidomide therapy. Men must agree not to father a child and agrees to use a condom if his partner is of child bearing potential.