I hate to say it too, but my husband's problems started when he first took Xtandi.
Yes, he had a problem with calcium from his bone tumours entering his blood stream, but that is now under control, and he continued to have no energy/appetite/zest for life.
The positive thing is that his MacMillan nurse prescribed two drugs which have helped a lot.
The first is a drug called Levomepromozine. This is usually used as an antipsychotic, but is also used in palliative care when patients have nausea/no appetite/anxiety etc
The second is a steroid called Dexamathasone
Since starting these drugs, he has had much more of an appetite, and is spending more time downstairs with the family, and less time in bed.
They both come under the 'palliative' remit, and may not give relief for a longer period of time - but as long as they are helping him feel better now, who cares?
Not sure if the drugs have a different name in the U.S (we're in the U.K) but might be worth a look.