Cytoxan (cyclophosphamide)

CYTOXAN® (cyclophosphamide) was first approved by the U.S. Food and Drug Administration (FDA) in 1959, and is still widely used to treat multiple myeloma, as well as many other types of cancer and autoimmune diseases. It belongs to the class of drugs known as alkylating agents, which inhibit DNA and RNA synthesis, causing the death of both dividing and non-dividing tumor cells.

How Is cyclophosphamide used?

Cyclophosphamide can be used throughout the myeloma disease course. As a first-line therapy, it is most commonly given orally in combination with Velcade (bortezomib) and dexamethasone (CyBorD or VCd). CyborD can also be used at first or subsequent relapse. Cyclophosphamiden is also given orally at relapse in combination with Revlimid® and dexamethasone (CRd) or Pomalyst® and dexamethasone (CPd).

Relapse regimens with intravenous (into the vein) cyclophosphamide therapy include:

• high-dose cyclophosphamide as a single agent
• dexamethasone/cyclophosphamide/etoposide/cisplatin (DCEP)
• dexamethasone/thalidomide - cisplatin/doxorubicin, cyclophosphamide/etoposide (DT-PACE)
• Velcade/thalidomide/dexamethasone - cisplatin/doxorubicin, cyclophosphamide/etoposide (VTD-PACE).

A cyclophosphamide infusion, or intravenous (IV) cyclophosphamide, can also be used as part of the stem cell harvesting process in combination with colony stimulating factors.

Possible Cyclophosphamide Side Effects

Cyclophosphamide side effects depend on how you receive it and at what dose. Oral cyclophosphamide is generally well tolerated, but can lower the blood counts. Because cyclophosphamide can irritate the bladder, patients should drink at least 2-3 quarts of water every 24 hours, unless instructed otherwise.

The most common side effects of IV cyclophosphamide include:

• low blood counts
• hair loss
• nausea and vomiting
• loss of appetite
• loss of fertility
• discoloration of the skin or nails.

Less common side effects are: 

• diarrhea
• mouth sores
• bladder problems, including irritation and bleeding.

Use of cyclophosphamide slightly increases the risk of developing myelodysplasia or leukemia.