These activating factors are known to be important for malignant transformation and progression. mTOR is particularly important in the biology of renal cancer (RCC) owing to its function in regulating HIF-1a levels. Mutation or loss of the von Hippel Lindau tumor-suppressor gene is common in RCC and is manifested by reduced degradation of HIF-1a. In RCC tumors, activated mTOR further exacerbates accumulation of HIF-1a by increasing synthesis of this transcription factor and its angiogenic target gene products. Efficacy
In an international three-arm phase III study with 626 previously untreated, poor-prognosis patients, temsirolimus, interferon-α and the combination of both agents was compared. Median overall survival improved significantly in the temsirolimus group (10.9 months) compared with interferon-α group (7.3 months) and the combination group (8.4 months). Further studies are needed to determine the role of temsirolimus in the first-line treatment of patients with a more favorable prognosis, how it can be combined with other targeted agents and as sequential therapy with sunitinib or sorafenib. Adverse reactions
The toxicity profile is based on what was found in the phase III trial. adverse reaction
fatigue
skin rash
mucositis
hematologic abnormalities
hemoglobin decreased
lymphocytes decreased
laboratory abnormalities
triglycerides increased
glucose increased
phosphorus decreasedTemsirolimus has been generally well tolerated in clinical settings by patients with advanced RCC. In patients with RCC, the adverse effect profile of temsirolimus is primarily metabolic in nature, with minimal impact on QoL compared with the commonly seen side-effects with oral multikinase inhibitors. Temsirolimus high level of specificity for mTOR likely contributes to the tolerability of temsirolimus. However, temsirolimus increases mortality in cancer patients.
Lung toxicity
Temsirolimus is associated with lung toxicity, and the risk of developing this complication may be increased among subjects with abnormal pre-treatment pulmonary functions or history of lung disease. The risk of interstitial lung disease is increased with temsirolimus doses greater than 25 mg, symptoms of which may include dry cough, fever, eosinophilia, chest pain, and dyspnea on exertion. Toxicity usually occurred early (within days to weeks) or late (months to years) after treatment. Dosing
Although infusion reactions can occur while temsirolimus is being administered, most hypersensitivity reactions occurring on the same day as temsirolimus administration were not severe. Antihistamine pretreatment (e.g. 25–50 mg diphenhydramine, 30 minutes prior to administration) is recommended to minimize the risk of an allergic reaction. See also
Discovery and development of mTOR inhibitors

References
External links
"Temsirolimus". Drug Information Portal. U.S. National Library of Medicine.