* documented concomitant severe bacterial or fungal infection * infection with hiv, hcv, hbv * age \<18 years * thrombocytopenia \<50,000 / ul, neutropenia \<500 / ul * women of childbearing age who do not use an effective contraceptive method. * pregnant or lactating women. * patients who do not want or cannot comply with the protocol. * patients with impaired gastrointestinal function or gastric disease that significantly impairs the absorption of ruxolitinib or simvastatin, such as: severe ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, extensive resection (\> 1m) of the small intestine or inability to swallow oral medication. previous partial or total gastrectomy is not an exclusion criterion

* documented concomitant severe bacterial or fungal infection * infection with hiv, hcv, hbv * age \<18 years * thrombocytopenia \<50,000 / ul, neutropenia \<500 / ul * women of childbearing age who do not use an effective contraceptive method. * pregnant or lactating women. * patients who do not want or cannot comply with the protocol. * patients with impaired gastrointestinal function or gastric disease that significantly impairs the absorption of ruxolitinib or simvastatin, such as: severe ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, extensive resection (\> 1m) of the small intestine or inability to swallow oral medication. previous partial or total gastrectomy is not an exclusion criterion

- documented concomitant severe bacterial or fungal infection - infection with hiv, hcv, hbv - age <18 years - thrombocytopenia <50,000 / ul, neutropenia <500 / ul - women of childbearing age who do not use an effective contraceptive method. - pregnant or lactating women. - patients who do not want or cannot comply with the protocol. - patients with impaired gastrointestinal function or gastric disease that significantly impairs the absorption of ruxolitinib or simvastatin, such as: severe ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, extensive resection (> 1m) of the small intestine or inability to swallow oral medication. previous partial or total gastrectomy is not an exclusion criterion

- documented concomitant severe bacterial or fungal infection - infection with hiv, hcv, hbv - age <18 years - thrombocytopenia <50,000 / ul, neutropenia <500 / ul - women of childbearing age who do not use an effective contraceptive method. - pregnant or lactating women. - patients who do not want or cannot comply with the protocol. - patients with impaired gastrointestinal function or gastric disease that significantly impairs the absorption of ruxolitinib or simvastatin, such as: severe ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, extensive resection (> 1m) of the small intestine or inability to swallow oral medication. previous partial or total gastrectomy is not an exclusion criterion