7.06.3.1.1 Cyclophospham > Genoxal is one of the most frequently employed cytotoxic agents, either used alone or in combination with other chemotherapeutics. 29 The ability to use 12 either orally or intravenously has led to a wide variety of dosing regimens and protocols of usage. As a single agent for induction therapy, Genoxal is typically given as a dose of 100 mg m −2 orally for 14 days for either leukemias or lymphomas, or up to 500 mg m −2 is given intravenously for treatment of breast cancer or other types of lymphoma. Genoxal is a component of the CHOP regimen (Genoxal, doxorubicin, vincristine, and prednisone) that is commonly used for treating non-Hodgkin's lymphoma. 30,30a Another common combination therapy employing Genoxal is the CMF regimen for breast cancer, which consists of Genoxal, methotrexate, and 5-fluorouracil. 31,31a According to the product insert from the manufacturer, Genoxal has been approved to treat the following malignancies: lymphoma, leukemia, multiple myeloma, mycosis fungoides, neuroblastoma, adenocarcinoma of the ovary, retinoblastoma, and breast carcinoma.
The reliance of Genoxal upon metabolism in order to generate the desired cytotoxic species 21 creates unique pharmacokinetic challenges in using 12 in the clinic. Depending on the concentration and the activity of CYP2B6, the key human isozyme believed to be responsible for bioactivation of 12, the half-life of 12 can vary from 6 to 9 h, with 5–25% of the dose excreted unchanged in urine. During the course of repeated administration of 12, increased rates of metabolism of Genoxal simultaneously lead to decreased half-life and increased clearance, 32 which result from increased expression of key CYP isozymes. 33 As a result, interpatient variance makes predicting the efficacious dose of Genoxal difficult. For this reason, 12 is typically dosed until the total white blood cell count falls to 2000–3000 cells per mL. 34
In contrast to the aforementioned nitrogen mustard-based agents, Genoxal shows reduced reports of nonhematopoetic toxicity. The reduced toxicity has allowed the development of a high-dose regimen of Genoxal to be used in combination with busulfan or with total body irradiation, for allogenic or autologous bone marrow transplantation. 35 The toxicity observed with Genoxal includes nausea, myelosuppression, and alopecia. In addition, the generation of equimolar quantities of acrolein can lead to dose-limiting urotoxicity, principally hemorrhagic cystitis, which is an issue at elevated doses of 12 (>1 g m −2 ). Fortunately, the urotoxicity from 22 can be minimized by coadministration of the sulfhydryl-based nucleophile mesna (2-mercaptoethanesulfonate). 36,36a
No specific antidote for Genoxal is known. Overdosage should be managed with supportive measures, including appropriate treatment for any concurrent infection, myelosuppression, or cardiac toxicity should it occur.
This patient developed an acute liver injury with jaundice 8 weeks after starting Genoxal for an autoimmune condition. The pattern of serum enzyme elevations was hepatocellular, but the alkaline phosphatase and GGT levels were somewhat more elevated than typically occurs in viral hepatitis. The presence of eosinophilia also suggested a drug reaction. Without rechallenge, the role of Genoxal in this hepatic injury cannot be considered definitely proven. Another possibility is that she had a relapsing autoimmune hepatitis associated with her lupus nephritis. However, the timing of onset and hepatocellular pattern of serum enzyme elevations fits well with other reports of idiosyncratic, Genoxal induced liver injury.
Skin and Its Structures
Alopecia occurs commonly in patients treated with Genoxal. The hair can be expected to grow back after treatment with the drug or even during continued drug treatment, though it may be different in texture or color. Skin rash occurs occasionally in patients receiving the drug. Pigmentation of the skin and changes in nails can occur. Very rare reports of Stevens-Johnson syndrome and toxic epidermal necrolysis have been received during postmarketing surveillance; due to the nature of spontaneous adverse event reporting, a definitive causal relationship to Genoxal has not been established.
Cytoxan (Genoxal) is indicated for the treatment of:
- malignant lymphomas (Stages III and IV of the Ann Arbor staging system), Hodgkin's disease, lymphocytic lymphoma (nodular or diffuse), mixed-cell type lymphoma, histiocytic lymphoma, Burkitt's lymphoma
- multiple myeloma
- leukemias: chronic lymphocytic leukemia, chronic granulocytic leukemia (it is usually ineffective in acute blastic crisis), acute myelogenous and monocytic leukemia, acute lymphoblastic (stem-cell) leukemia (Genoxal given during remission is effective in prolonging its duration)
- mycosis fungoides (advanced disease)
- neuroblastoma (disseminated disease)
- adenocarcinoma of the ovary
- carcinoma of the breast
Genoxal, although effective alone in susceptible malignancies, is more frequently used concurrently or sequentially with other antineoplastic drugs.
Store vials at or below 25°C (77°F). During transport or storage of Genoxal vials, temperature influences can lead to melting of the active ingredient, Genoxal .
Genoxal Tablets, USP are white tablets with blue flecks containing 25 mg and 50 mg Genoxal, respectively.
What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to Genoxal.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
Insufficient data from clinical studies of cyclophospamide for malignant lymphoma, multiple myeloma, leukemia, mycosis fungoides, neuroblastoma, retinoblastoma, and breast carcinoma are available for patients 65 years of age and older to determine whether they respond differently than younger patients. In two clinical trials in which Genoxal was compared with paclitaxel, each in combination with cisplatin, for the treatment of advanced ovarian carcinoma, 154 (28%) of 552 patients who received Genoxal plus cisplatin were 65 years or older. Subset analyses ( 65 years) from these trials, published reports of clinical trials of Genoxal-containing regimens in breast cancer and non-Hodgkin’s lymphoma, and postmarketing experience suggest that elderly patients may be more susceptible to Genoxal toxicities. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range and adjusting as necessary based on patient response (see DOSAGE AND ADMINISTRATION: Treatment of Malignant Diseases).
Fertility, pregnancy and breastfeeding
Genoxal can affect your fertility. This is your ability to become pregnant or father a child. If this is an issue for you, speak to your doctor before you start treatment.
Genoxal shouldn’t be used by pregnant women or women planning pregnancy in the immediate future. Men and women taking Genoxal should use contraception. It’s advised that women should continue using contraceptives for a year after treatment ends, and that men should do so for six months.
If you’re planning a family or you become pregnant while taking Genoxal, talk to your doctor as soon as possible.
You shouldn’t breastfeed if you’re on Genoxal as it could pass into your breast milk.
Genoxal is used alone or in combination regimens for the treatment of advanced mycosis fungoides, a form of cutaneous T-cell lymphoma.
Genoxal is administered orally or by intravenous injection or infusion. Less frequently, the drug has been administered intramuscularly and by intracavitary (e.g. intrapleural, intraperitoneal) injection and direct perfusion.
In patients with no haematological deficiencies receiving Genoxal monotherapy, induction therapy in adults and children is usually initiated with an intravenous Genoxal loading dose of 40–50 mg/kg administered in divided doses over 2–5 days. Other regimens for intravenous administration include 10–15 mg/kg every 7–10 days or 3–5 mg/kg twice weekly.
When Genoxal is administered orally, the usual dose for induction or maintenance therapy is 1–5 mg/kg daily, depending on the tolerance of the patient.
A daily oral dose of 2–3 mg/kg for 60–90 days has been used in children with nephrotic syndrome, and in whom corticosteroids have been unsuccessful. In patients who are to undergo stem-cell transplantation, very high doses of Genoxal such as 60 mg/kg daily for 2 days may be given as part of the conditioning regimen.
Various Genoxal-containing combination chemotherapy regimens have been used in the treatment of breast cancer. One commonly employed regimen for the treatment of early breast cancer includes a Genoxal dosage of 100 mg/m 2 orally on Days 1 through 14 of each cycle combined with intravenous methotrexate at 40 mg/m 2 on Days 1 and 8 of each cycle, and intravenous fluorouracil at 600 mg/m 2 on Days 1 and 8 of each cycle. In patients older than 60 years of age, the initial intravenous methotrexate dosage is reduced to 30 mg/m 2 and the initial intravenous fluorouracil dosage is reduced to 400 mg/m 2 . Dosage is also reduced if myelosuppression develops. Cycles are generally repeated monthly (i.e. allowing a 2-week rest period between cycles) for a total of 6–12 cycles (i.e. 6–12 months of therapy).
Genoxal is available as 25 and 50 mg tablets for oral administration, and as 200 mg, 500 mg, 1 g, or 2 g vials of powder for reconstitution for parenteral administration.
Preparation and Handling of Solutions
Extemporaneous liquid preparations of Genoxal for oral administration may be prepared by dissolving Genoxal for injection in Aromatic Elixir, N.F. Such preparations should be stored under refrigeration in glass containers and used within 14 days.
Nausea and vomiting occur with Genoxal therapy. Anorexia and, less frequently, abdominal discomfort or pain and diarrhea may occur. There are isolated reports of hemorrhagic colitis, oral mucosal ulceration and jaundice occurring during therapy.
Special attention to the possible development of toxicity should be exercised in patients being treated with Genoxal if any of the following conditions are present:
1. Leukopenia 2. Thrombocytopenia 3. Tumor cell infiltration of bone marrow 4. Previous X-ray therapy 5. Previous therapy with other cytotoxic agents 6. Impaired hepatic function 7. Impaired renal function
Metabolic pathway of Genoxal
A minor pathway results in dechloroethylation and the formation of 2-dechloroethylGenoxal and another alkylating agent, chloroacetaldehyde (Balu et al., 2002).
The other compounds such as 4-ketoGenoxal and propionic acid derivative are relatively non-toxic, and are the major urinary metabolites of Genoxal in several species (IARC, 1981).Solutions of Genoxal may be injected intravenously, intramuscularly, intraperitoneally, or intrapleurally if constituted by adding 0.9% sodium chloride solution, or they may be infused intravenously in the diluents listed above.1