Welcome, @terdor! MDS treatments aren’t “one size fits all” because there are variables with each person. I’m sorry your husband didn’t respond well to the Vidaza alone. The Decitabine/Venetoclax can have positive results as you’ve seen with some of the posts here in this discussion. So we’ll be optimistic that this will be the charm for your husband. ☺️

His doctor is right, the blood numbers may get lower before they get better with this treatment. I know that can feel like a setback or huge disappointment. But it’s vitally important to clear out the blast cells. While there are only 10% in his circulating blood, (there shouldn’t really be any) that means there are much more in his bone marrow, interfering with healthy blood cell production. So once those blast cells (immature, defective white blood cells) are killed off with the chemo, your husband’s marrow will have more of an opportunity to help replenish his body with healthy cells. That’s the goal.

So hang in there! Blood and platelet infusions may help him to feel better and keep his numbers reasonable in the meantime.
How has your husband been doing with his treatment for prostate cancer?