Cyclophosphamide is a decades-old chemotherapy agent tried and tested for other cancers such as breast cancer, ovarian cancer and leukemia. For mesothelioma, however, it remains in the testing phases. One study showed a combination of cyclophosphamide and doxorubicin extended progression-free survival by 1.5 months.

Cyclophosphamide Information


  • Other names: Clafen, Cytoxan, Neosar
  • Manufactured by: Roxane Laboratories
  • FDA-approved: Yes
  • Used or tested in: Breast cancer, leukemia, lymphoma, mesothelioma, myeloma, neuroblastoma, ovarian cancer, retinoblastoma

Researchers have already proven the safety and efficacy of cyclophosphamide, manufactured by Roxane Laboratories, in other diseases. The Food and Drug Administration (FDA) approved it for use in a number of cancers and diseases, including breast cancer and leukemia.

Doctors have seen mixed results in clinical trials but remain hopeful that the drug can be implemented successfully in mesothelioma treatment regimens. Now, researchers are studying its effects in combination with other chemotherapy drugs and in combination with immunotherapy.

How is it Used?

Unlike traditional chemotherapy drugs that must be administered intravenously, cyclophosphamide may also be administered in tablet form, once or twice daily, or injection. Mesothelioma patients in clinical trials usually receive the drug in the traditional intravenous manner, typically once every two weeks.

Cyclophosphamide is an alkylating agent, which means it is designed to inhibit tumor growth by interfering with the DNA of cancer cells. It can bind with DNA in mesothelioma cells. Once it does so, it prevents cell division and prompts the death of cancer cells.

What are the Side Effects?

Cyclophosphamide comes with the general side effects of chemotherapy such as fatigue, weight loss, nausea and hair loss. It may cause additional side effects of abdominal pain, chest pain or shortness of breath, which usually are not severe.

However, doctors have noted one major potential side effect: an increased risk of other types of cancer. Long-term use and high doses create the greatest risk. Bladder cancer is the most common resulting cancer, which may develop years after use.

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Study Results

Researchers have had mixed results when testing cyclophosphamide in mesothelioma patients. One study had positive results when patients underwent radiation therapy followed by a chemotherapy regimen of cyclophosphamide and doxorubicin. Adding the chemotherapy regimen caused tumors to decrease in size by about 25 percent. Overall, patients who received radiation therapy and chemotherapy survived a median of 13 months, as compared with only six months in patients who received radiotherapy alone. However, these results may be slightly skewed since chemotherapy was only given to those patients who were 70 or younger and who responded well to initial radiation therapy.

A more recent study from 2010 combined cyclophosphamide with doxorubicin and platinum-based chemotherapy. Success was measured by progression-free survival, or the amount of time that passes after treatment until the cancer spreads. In patients receiving this chemotherapy combination, median progression-free survival was only 1.5 months. This was significantly shorter than the median 12.3 months achieved by a regimen of pemetrexed and platinum-based chemotherapy.

Doctors see promise in cyclophosphamide for the treatment of mesothelioma, and clinical trials continue. Ongoing studies are testing the chemotherapy agent in conjunction with immunotherapy or other chemotherapy drugs for use in treating mesothelioma patients.

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Karen Selby joined in 2009. She is a registered nurse with a background in oncology and thoracic surgery and was the director of a tissue bank before becoming a Patient Advocate at The Mesothelioma Center. Karen has assisted surgeons with thoracic surgeries such as lung resections, lung transplants, pneumonectomies, pleurectomies and wedge resections.

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