Temsirolimus Promising for Treatment of Breast Cancer, Mantle Cell Lymphoma
According to three studies published in the Journal of Clinical Oncology, treatment with the investigational drug temsirolimus, a cell signal blocker, may be effective against several types of cancer.
Temsirolimus is an agent that controls the growth of cells by blocking cell signals and preventing cell division. Temsirolimus has been given “fast track” status by the Food and Drug Administration (FDA) for the treatment of advanced kidney cancer. Fast track designation does not guarantee eventual FDA approval, but it helps speed the development of drugs intended to treat life-threatening conditions for which there are few other treatment options.
In addition to kidney cancer, several other types of cancer may also respond to treatment with temsirolimus. Three phase II clinical trials published in the Journal of Clinical Oncology evaluate the effect of temsirolimus in patients with breast cancer, mantle cell lymphoma, and glioblastoma multiforme (a type of brain tumor).
The effectiveness of temsirolimus for the treatment of breast cancer was evaluated in a study of 109 women with locally advanced or metastatic (stage IIIB or IV) breast cancer. All of the women had previously been treated with chemotherapy. Patients were randomly assigned to receive either 75 or 250 mg of temsirolimus once a week for six months. Ten of the women (9%) experienced a partial shrinkage of their cancer following treatment. None of the women experienced a complete disappearance of cancer. The two treatment doses had a similar anti-cancer effect, but the higher dose produced more side effects. The most common severe adverse effects were inflammation of mucous membranes, low white blood cell levels, high blood sugar, sleepiness, low blood platelet levels, and depression. The researchers conclude that among women with stage IIIB or IV breast cancer, both doses of temsirolimus had anti-cancer activity, with fewer adverse effects of treatment following the lower dose.
The study of temsirolimus for treatment of lymphoma involved 35 patients with relapsed or refractory mantle cell lymphoma. Mantle cell lymphoma is an aggressive type of B-cell non-Hodgkin’s lymphoma. Patients were treated with 250 mg of temsirolimus per week. Twelve patients (35%) experienced a reduction in detectable lymphoma after treatment. One patient (3%) experienced a complete disappearance of detectable lymphoma. The most common adverse effect of treatment was low blood platelet levels. The researchers conclude that treatment with temsirolimus results in a substantial anti-lymphoma response in this poor-prognosis patient population.
Glioblastoma multiforme is the most common type of brain tumor in adults. Half of patients with this diagnosis survive for less than 15 months. To evaluate the effect of temsirolimus among patients with glioblastoma, researchers treated 65 patients with glioblastoma with 250 mg of temsirolimus per week. Twenty patients (36 percent) had a reduction in their tumor after treatment, and patients who responded to treatment survived longer than patients without response. Severe adverse effects of treatment included low blood platelet levels, high blood cholesterol levels, high blood triglyceride levels, high blood sugar, rash, and fatigue. The researchers conclude that while more study is needed, temsirolimus may benefit some subgroups of patients with glioblastoma.
These three studies suggest that temsirolimus may have activity against several types of cancer. Patients may wish to talk with their doctor about the risks and benefits of participating in a clinical trial further evaluating temsirolimus or other promising therapeutic approaches.
References: Chan S, Scheulen ME, Johnston S, et al. Phase II study of temsirolimus (CCI-779), a novel inhibitor of mTOR, in heavily pretreated patients with locally advanced or metastatic breast cancer. Journal of Clinical Oncology . 2005;23:5314-5322.
Witzig TE, Geyer SM, Ghobrial I, et al. Phase II trial of single-agent temsirolimus (CCI-779) for relapsed mantle cell lymphoma. Journal of Clinical Oncology . 2005;23:5347-5356.
Galanis E, Buckner JC, Maurer MJ, et al. Phase II trial of temsirolimus (CCI-779) in recurrent glioblastoma multiforme: A North Central Cancer Treatment Group Study. Journal of Clinical Oncology. 2005;23:5294-5304.