How it is administered

Temsirolimus is given as an intravenous (IV) infusion. The recommended dose is 25 mg administered over a 30–60 minute period once a week. The medication must be diluted with a special diluent provided in the kit before being further diluted in 0.9% Sodium Chloride Injection. An antihistamine (such as diphenhydramine) is recommended before each infusion to help prevent allergic reactions. The infusion is usually given in a hospital or clinic setting by a healthcare professional.

How it works

Temsirolimus is an inhibitor of mTOR (mammalian target of rapamycin), a protein that plays a key role in cell growth, division, and survival. By blocking mTOR, temsirolimus interferes with the signals that tell cancer cells to grow and divide. This leads to a halt in the cell cycle (specifically at the G1 phase), preventing tumor cells from multiplying.

In laboratory studies, temsirolimus has been shown to reduce the levels of proteins that help cancer cells survive under low-oxygen conditions and to decrease the formation of new blood vessels that tumors need to grow. Its main use is in cancers where mTOR signaling is abnormally active, such as advanced renal cell carcinoma. Although its primary FDA approval is for kidney cancer, temsirolimus has also been studied in some blood cancers and other solid tumors due to its effects on cell growth and immune function.

Who Should take it

Temsirolimus is approved for adults with advanced renal cell carcinoma (a type of kidney cancer). While its main indication is kidney cancer, it has also been studied in patients with certain blood cancers and solid tumors, especially when other treatments have not worked or are not suitable.

Your doctor may consider temsirolimus if you have advanced cancer that is not responding to standard therapies, particularly if your cancer is known to have abnormal mTOR pathway activity. The decision to use temsirolimus will depend on your specific diagnosis, overall health, and previous treatments.

Who should not take it

Temsirolimus should not be used in patients with significant liver impairment, specifically those with bilirubin levels greater than 1.5 times the upper limit of normal. It is also contraindicated in anyone with a known allergy to temsirolimus, its metabolites (such as sirolimus), or any of the components in the formulation (including polysorbate 80).

Patients who are pregnant or planning to become pregnant should not take temsirolimus, as it can cause harm to an unborn baby. Caution is also advised in people with a history of severe allergic reactions, those who have recently had surgery (due to potential wound healing problems), or those with active infections.

Commonly used with

Temsirolimus is sometimes used in combination with other cancer treatments, but combining it with certain drugs (such as sunitinib) has been associated with increased toxicity and is generally not recommended. It is important to tell your doctor about all other medications you are taking, as temsirolimus can interact with drugs that affect liver enzymes (CYP3A4 inducers or inhibitors), such as some antibiotics, antifungals, anti-seizure medications, and certain herbal supplements like St. John’s Wort.

It may also be used alongside supportive medications, such as antihistamines (to prevent allergic reactions) and drugs to control blood sugar or cholesterol.

Commonly tested with

Temsirolimus has been studied in combination with interferon alfa (IFN-α) in clinical trials for kidney cancer. However, the combination did not show a significant benefit over temsirolimus alone and was associated with more side effects.

In research settings, temsirolimus has also been tested with other chemotherapy agents and targeted therapies, but such combinations are not standard and should only be used in a clinical trial or under close medical supervision.