How much effective are chemotherapeutic agents in treating MS?

Many chemotherapeutic agents have undergone clinical trials, some have been used in uncontrolled studies, and most remain controversial due to mixed results and severe side effects that include risk of infection, sterility, mutations, hair loss, nausea, and increased risk of cancer. For the most part, a newer drug, Novantrone, is a better choice. But here are other options.

Cyclophosphamide (Cytoxan) is currently being studied for those with rapidly progressing disease. Cyclosporine A , best known as a drug that significantly reduced rejection rates in organ transplants, has been studied and found to slow disease progression, but not enough to change performance of daily activities. Azathioprine (Imuran) is commonly used in rheumatoid arthritis and some cancers. The benefits of these drugs must be weighed against their risks.