Insurance & Medication

I am on medicare with a part D supplement from Cigna. I an currently taking Veltassa which is over $900.00 of which Cigna pays half. I now need to take double the dosage which is over $900.00 out of pocket. Does anyone have a Part D that covers Veltassa as a tier 1 medication? I cannot afford almost $1000.00 a month out of pocket, not to mention the 10 other meds I am taking. One of my meds comes from Israel because it is much less but also totally out of pocket.