Hypersensitivity/infusion reactions (e.g. anaphylaxis, apnea, dyspnea, flushing, loss of consciousness, hypotension, and/or chest pain) reported. Infusion reaction may occur with initial or subsequent infusions. Use with caution in hypersensitivity to polysorbate 80. Angioedema reported (concurrent use with other drugs known to cause angioedema (e.g. ACEIs) may increase risk). Cases of bowel perforation (fatal) have occurred. Treatment may result in immunosuppression, may increase risk of opportunistic infections and/or sepsis. Interstitial lung disease, sometimes fatal, reported. Acute renal failure with rapid progression reported, including cases unresponsive to dialysis. May be associated with impaired wound healing (use caution in perioperative period). CNS metastases/tumors may be at increased risk for developing intracerebral bleeding. Increases in serum glucose common, may alter insulin and/or oral hypoglycemic therapy requirements in diabetes. Use with caution in hepatic impairment. Temsirolimus predominantly cleared by liver. Use with caution in hyperlipidemia, may increase serum lipids (cholesterol and triglycerides). Patients receiving anticoagulant therapy may be at increased risk for developing intracerebral bleeding. Use with caution in patients taking strong CYP3A4 inhibitors and moderate or strong CYP3A4 inducers. Patients should not be immunized with live viral vaccines during or shortly after treatment and should avoid close contact with recently vaccinated (live vaccine) individuals.