CHOP is one of the most common chemotherapy regimens for treating Non-Hodgkin’s lymphoma.
The following are the drugs used in the regimen.Cyclophosphamide (brand names cytoxan, neosar)
Adriamycin (doxorubicin / hydroxydoxorubicin (ref))
Prednisone (sometimes called Deltasone or Orasone)
CHOP is sometimes used in conjunction with immunotherapy drugs such as Rituxan to see is the combination will produce better results. This may be abbreviated CHOP-R or CHOP+R.
One of the most common ciomplications of CHOP chemotehrapy is tumor lysis syndrome. Tumor lysis syndrome (TLS) is the development of electrolyte and metabolic disturbances that may occur following the treatment of cancer and can result in life-threatening complications if not managed appropriately. Tumor lysis syndrome is caused by the sudden, rapid death of cells, particularly cancer cells in patients with leukemia or lymphoma, in response to cancer therapies. When cancer cells are killed by therapy, they may spill their inner (intracellular) contents, which accumulate in the body faster than can be eliminated. These intracellular contents cause the metabolic and electrolyte disturbances that result in TLS. Tumor lysis syndrome may also occur spontaneously; however, this is rare.
One of the most common and serious abnormalities of TLS is hyperuricemia. Hyperuricemia refers to excess uric acid in the blood. Uric acid is the end product of the digestion of certain proteins and is normally eliminated through the urine. When excess uric acid is present, it is converted to crystals formed of sodium urate. These crystals may deposit in the tiny tubes that are part of the kidney and cause acute kidney damage, which can ultimately lead to kidney failure. Treatment for hyperuricemia may include intravenous administration of fluids, diuretics to promote excretion of uric acid in the urine, or allopurinol to reduce the formation or uric acid and the alkalinization of urine.
According to results recently published in the Journal of Clinical Oncology, Elitek? (rasburicase) should be considered the treatment of choice for maintaining normal uric acid levels and preventing tumor lysis syndrome associated with high uric acid levels in adult patients with aggressive non-Hodgkin?s lymphoma who are receiving treatment with chemotherapy.
All studies were done in the pediatric age group. ELITEK is indicated for the initial management of plasma uric acid levels in pediatric patients with leukemia, lymphoma, and solid tumor malignancies who are receiving anti-cancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid.
The proposed use is off-label but it is hard to amke the case that it is not effective in the adult age group. Once teh FDA approval for a supportive care drug is obtained, no fartehr studies would likely be done. The drug is clear for marketing and tehe xperts would agree that fartehr studies are not encessary. For this reason, I consider the drug to be not experimental and medically necessary.
Imrie K, Stevens A, Meyer R, Hematology Disease Site Group. Rituximab in lymphoma and chronic lymphocytic leukemia: a clinical practice guideline. Toronto (ON): Cancer Care Ontario (CCO); 2005 Dec 22. 46 p. (Evidence-based series; no. 6-8). [65 references]
Coiffier B, Mounier N, Bologna S, et al. Efficacy and safety of rasburicase (recombinant urate oxidase) for the prevention and treatment of hyperuricemia during induction chemotherapy of aggressive non-Hodgkin?s lymphoma: results of the GRAALI1 (Group d?Etude des lymphomas de l?Adulte trial on rasburicase activity in adult lymphoma) study. Journal of Clinical Oncology. 2003;21:4402-4406.