Diagnosed with MDS, what is a Paradox Effect with Vidaza

After 6 months of treatment with Vidaza it appears that according to my doctor I may be experiencing a Paradox Effect. This effect is shown when the white blood cells do not return to a normal level after treatment with Vidaza. The doctor is skipping a treatment of Vidaza in hopes of isolating whether or not Vidaza is working. Has anyone heard of this Paradox Effect and if Vidaza is no longer effective then what are the alternatives? Thank you for any responses to this.