Cyclophosphamide

An alkylating anticancer agent with another strategy to lower the toxicities on normal cells and increase the specifi city for cancer cells was attempted by O.M. Friedman and A.M. Seligman at Harvard University in 1949. Based on the previous fi nding that cancer cells have higher phosphamidase activity, they predicted that if the activity of this enzyme were used to develop a drug that existed as an innocuous prodrug that becomes activated by phosphoamidases inside the cancer cells, this could specifi cally eliminate cancer cells [12]. However, it was later determined that this active form is generated by a different drug metabolic pathway, contrary to the initial assumption that phosphamidases would be involved. In other words, cyclophosphamide is mostly activated to 4-hydroxycyclophosphamide by cytochrome P450 enzymes in the liver microsomes, secreted to the bloodstream, and absorbed by cancer cells.With the therapeutic effect of cyclophosphamide verifi ed in clinical tests on patients with malignant lymphoma, it was registered as an FDA-approved lymphoma anticancer agent in 1959. Later, cyclophosphamide has been widely used in anticancer treatment for not only lymphocytic leukemia such as Hodgkin’s lymphoma, Burkitt lymphoma, childhood acute lymphoblastic leukemia, chronic granulocytic leukemia, acute myeloid leukemia, and multiple myeloma, but also solid cancers such as breast cancer, ovarian cancer, and sarcoma.

Cyclophosphamide is one of the most successful anticancer agents ever synthesized. Even today, 50 years after its synthesis, cyclophosphamide is still widely used as a chemotherapeutic agent and in the mobilization and conditioning regimens for blood and marrow trans plantation (BMT). Among 1,000 selected compounds and antibiotics tested against 33 tumors, cyclophosphamide was the most effective molecule. The initial clinical trials^{[1, 2]} of cyclophosphamide for the treatment of cancer were performed in 1958, and in 1959 it became the eighth cytotoxic anticancer agent approved by the FDA. It is also approved for minimal change disease of the kidney in children (a disease that causes nephrotic syndrome), but despite its widespread use in other autoimmune disorders and BMT, it has never been approved for these indications.

Figure 1 the chemical structure of cyclophosphamide;

The chemical design of cyclophosphamide—substitution of an oxazaphosphorine ring for the methyl group of nitrogen mustard—was based on the rationale that some cancer cells express high levels of phosphamidase, which is capable of cleaving the phosphorus–nitrogen (P–N) bond, releasing nitrogen mustard.^[3] Thus, cyclophosphamide was one of the first agents rationally designed to selectively target cancer cells. Although cyclophosphamide is in fact a prodrug that requires metabolic activation, the original hypothesis that it would function as targeted anticancer therapy via phosphamidase activation proved to be inaccurate.
The cytotoxic action of nitrogen mustard is closely related to the reactivity of the 2chloroethyl groups attached to the central nitrogen atom. Under physiological conditions, nitrogen mustards undergo intramolecular cyclizations through elimination of chloride to form a cyclic aziridinium (ethyleneiminium) cation.
This highly unstable cation is readily attacked on one of the carbon atoms of the three-member aziridine ring by several nucleophiles, such as DNA guanine residues (Figure 1). ^[5] This reaction releases the nitrogen of the alkylating agent and makes it available to react with the second 2chloroethyl side chain, forming a second covalent linkage with another nucleophile, thus interfering with DNA replication by forming intrastrand and interstrand DNA crosslinks. In contrast to aliphatic (or open chain) nitrogen mustards, cyclophosphamide is an inactive prodrug that requires enzymatic and chemical activation to release active phosphoramide mustard. Hydroxylation on the oxazaphosphorine ring by the hepatic cytochrome P450 system generates 4-hydroxycyclophosphamide, which coexists with its tautomer, aldophosphamide.
The major mechanism of cyclophosphamide detoxification is oxidation of aldophosphamide to carboxyphosphamide by cellular aldehyde dehydrogenase (AlDH). ^[7] withdrawal of the hydrogen adjacent to the aldehyde, by a base, is a necessary step for decomposition of aldophosphamide. Conversion of the aldehyde to carboxylic acid by AlDH makes this hydrogen less acidic for removal,^[8] subsequently releasing the active phosphoramide mustard. Thus, cellular concentrations of AlDH are serendipitously responsible for many of the differential activities of cyclophosphamide in cells. ^[9] Carboxyphosphamide and its degradation products are the major metabolites found in urine. ^[10]
Although AlDH1A1 expression is the major determinant of normal cellular sensitivity to cyclophosphamide and is associated with resistance to cyclophosphamide in tumor cell lines, ^[11] it has a minor role in the clinical response of cancer cells to cyclophosphamide^{[9, 12]}. In particular, leukemia and lymphoma specimens from newly diagnosed patients rarely express high levels of AlDH isozymes^[9] Increased cellular levels of glutathione and glutathione S-transferases have been shown to cause cyclophosphamide resistance in tumor cell lines, but the lack of a similar correlation in vivo suggests that this is not the major mechanism contributing to cyclophosphamide resistance^[12]. The inherent sensitivity of cancer cells to undergo apoptosis following DNA damage is the most important determinant of the clinical sensitivity of cancer cells to cyclophosphamide^{[13, 14]}.

Bone marrow suppression is the most common toxic effect of cyclophosphamide. Neutropenia is dose dependent. Patients treated with low-dose cyclophosphamide should be monitored closely, although they rarely develop significant neutropenia. Leukopenia, thrombocytopenia and anemia are common after high dose cyclophosphamide administration. Rapid hematologic recovery invariably occurs within 2–3 weeks in patients with normal bone marrow reserve, regardless of the dose.
Cardiotoxicity is the dose limiting toxic effect of cyclophosphamide, and is observed only after administration of high doses. The cardiac manifestations that result from high dose cyclophosphamide are heterogeneous and range from innocuous to fatal. The most severe form is hemorrhagic necrotic perimyocarditis, with a reported incidence of <1–9% after the most commonly used high doses of cyclophosphamide (60 mg/kg daily × 2 days or 50 mg/kg daily × 4 days) ^{[15, 16]}. However, in most transplant centers the rate of hemorrhagic myocarditis is less than 0.1%. This clinical syndrome occurs abruptly within days of drug infusion and is fatal. Perimyocarditis is manifested by severe congestive heart failure accompanied by electro cardiographic findings of diffuse voltage loss, cardio megaly, pleural and pericardial effusions. Postmortem findings reveal hemorrhagic cardiac necrosis.
Gonadal failure is a major complication of cyclophosphamide administration, especially in females. The patient’s age at treatment, the cumulative dose, and the administration schedule are major determinants for this adverse effect. The risk for sustained amenorrhea in patients with lupus receiving monthly intermediate dose cyclophosphamide is 12% for women under 25 years of age, and greater than 50% for women over 30 years of age. The risk for ovarian failure following high dose cyclophosphamide administration seems to be less than that of intermediate dose.
Hemorrhagic cystitis is the most common form of cyclophosphamide bladder toxicity,^[17] but bladder fibrosis and transitional or squamous cell carcinoma can also occur. Hemorrhagic cystitis can occur early or late after cyclophosphamide administration. Early onset disease, in the first few days after cyclophosphamide administration, seems to be caused by acrolein^[18]. Vigorous hydration, forced diuresis and MESNA, which interacts with acrolein to form nontoxic adducts, can prevent acute hemorrhagic cystitis by limiting uroepithelial exposure to acrolein^[19]. Hemorrhagic cystitis can develop weeks to months after treatment in 20–25% of patients who receive high dose cyclophosphamide.
Cyclophosphamide is carcinogenic. In addition to bladder cancer, secondary acute leukemia (often preceded by myelodysplastic syndrome) and skin cancer are the most common malignancies after cyclophosphamide therapy. The probability of acquiring a therapy-related malignancy is proportional to the length of drug exposure and cumulative dose. Therapy-related leukemia occurs in roughly 2% of patients treated with chronic cyclophosphamide, primarily in patients who have received the drug for more than 1 year^[20].

Cyclophosphamide is one of the few drugs with a broad indication for cancer. Although it is effective as a single agent in malignancies, it is usually used in combination with other antineoplastic agents. Even though it has been substituted by newer agents (such as platinums, taxanes and targeted therapies) for the treatment of many solid tumors, it is quite active for many of these indications, and there often remains limited evidence for the superiority of the newer approaches.
Cyclophosphamide based therapy is used extensively for lymphomas and is often curative for aggressive non-Hodgkin lymphoma, with Burkitt lymphoma being particularly sensitive. Although modern therapeutic regimens employ intensive cyclophosphamide based combination chemotherapy^[21], in the 1960s durable complete remissions were reported following a single course of cyclophosphamide.^[22] RCHoP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) remains the most commonly employed regimen for aggressive non-Hodgkin lymphoma, with cure rates of 30–40%. Many newer cyclophosphamide based multidrug combinations have been developed for aggressive non-Hodgkin lymphoma, but none have proven to be superior to CHoP.^[23] Myeloablative therapy, usually including high dose cyclophosphamide, followed by BMT is the most effective treatment for relapsed aggressive non-Hodgkin lymphoma.
Cyclophosphamide, in combination with other agents, has been the mainstay of adjuvant and metastatic breast cancer chemotherapy regimens such as CMF (cyclophosphamide, methotrexate, 5-fluorouracil) and FEC (5-fluorouracil, epirubicin, cyclophosphamide) for decades. AC (doxorubicin, cyclophosphamide) was demonstrated to be equivalent to 6 months of classic CMF in two separate National surgical Adjuvant Breast and Bowel Project (NsABP) studies^{[24, 25]}. The addition of a sequential taxane to this adjuvant regimen further improved outcomes and has since become the standard of care for human epidermal growth factor receptor 2 (HER2) negative early-stage breast cancer.
Cyclophosphamide is the cornerstone of curative chemotherapy regimens for numerous newly diagnosed and recurrent pediatric malignancies. Combinations of carboplatin and etoposide, and vincristine, cyclophosphamide and doxorubicin (CAdo), showed 5 year overall and event free survival rates of over 90% in infants with initial localized and unresectable neuroblastoma as well as allowance for subsequent surgical excision.^[27] Cyclophosphamide in combination chemotherapy regimens as an adjunct to surgery and radiation has also been used in a variety of rare cancers such as retinoblastoma, wilms tumor, and rhabdomyosarcoma as well as Ewing sarcoma.

1. Brock, N. & Wilmanns H. Effect of a cyclic nitrogen mustard-phosphamidester on experimentally induced tumors in rats; chemotherapeutic effect and pharmacological properties of B518 ASTA [German]. Dtsch. Med. Wochenschr. 83, 453–458 (1958).
2. Gross, R. & Wulf, G. Klinische und experimentelle Erfahrungen mit zyk lischen und nichtzyklischen Phosphamidestern des N-Losl in der Chemotherapie von Tumoren [German]. Strahlentherapie 41, 361–367 (1959).
3. Friedman, O. M. & Seligman, A. M. Preparation of N-phosphorylated derivatives of bis-P-chloroethylamine. J. Amer. Chem. Soc. 76, 655–658 (1954).
4. Arnold, H., Bourseaux, F. & Brock, N. Chemotherapeutic action of a cyclic nitrogen mustard phosphamide ester (B 518-ASTA) in experimental tumours of the rat. Nature 181, 931 (1958).
5. Dong, Q. et al. A structural basis for a phosphoramide mustard-induced DNA interstrand cross-link at 5'-d(GAC). Proc. Natl Acad. Sci. USA 92, 12170–12174 (1995).
6. Boddy, A. v. & Yule, S. M. Metabolism and pharmacokinetics of oxazaphosphorines. Clin. Pharmacokinet. 38, 291–304 (2000).
7. Chen, T. L. et al. Nonlinear pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide/aldophosphamide in patients with metastatic breast cancer receiving high-dose chemotherapy followed by autologous bone marrow transplantation. Drug Metab. Dispos. 25, 544–551 (1997).
8. Silverman, R. B. The Organic Chemistry of Enzyme-catalyzed Reactions (Academic Press, 2002).
9. Russo, J. E., Hilton, J. & Colvin, O. M. The role of aldehyde dehydrogenase isozymes in cellular resistance to the alkylating agent cyclophosphamide. Prog. Clin. Biol. Res. 290, 65–79 (1989).
10. Joqueviel, C. et al. Urinary excretion of cyclophosphamide in humans, determined by phosphorus-31 nuclear magnetic resonance spectroscopy. Drug Metab. Dispos. 26, 418–428 (1998).
11. Sladek, N. E. Leukemic cell insensitivity to cyclophosphamide and other oxazaphosphorines mediated by aldehyde dehydrogenase(s). Cancer Treat. Res. 112, 161–175 (2002).
12. Tanner, B. et al. Glutathione, glutathione S-transferase alpha and pi, and aldehyde dehydrogenase content in relationship to drug resistance in ovarian cancer. Gynecol. Oncol. 65, 54–62 (1997).
13. Banker, D. E., Groudine, M., Norwood, T. & Appelbaum, F. R. Measurement of spontaneous and therapeutic agent-induced apoptosis with BCL-2 protein expression in acute myeloid leukemia. Blood 89, 243–255 (1997).
14. Zhang, J., Tian, Q., Chan, S. Y., Duan, W. & Zhou, S. Insights into oxazaphosphorine resistance and possible approaches to its circumvention. Drug Resist. Updat. 8, 271–297 (2005).
15. Murdych, T. & Weisdorf, D. J. Serious cardiac complications during bone marrow transplantation at the University of Minnesota, 1977–1997. Bone Marrow Transplant. 28, 283–287 (2001).
16. Cazin, B. et al. Cardiac complications after bone marrow transplantation. A report on a series of 63 consecutive transplantations. Cancer 57, 2061–2069 (1986).
17. Stillwell, T. J. & Benson, R. C. Jr Cyclophosphamide-induced hemorrhagic cystitis. A review of 100 patients. Cancer 61, 451–457 (1988).
18. Cox, P. J. Cyclophosphamide cystitis— identification of acrolein as the causative agent. Biochem. Pharmacol. 28, 2045–2049 (1979).
19. Haselberger, M. B. & Schwinghammer, T. L. Efficacy of mesna for prevention of hemorrhagic cystitis after high-dose cyclophosphamide therapy. Ann. Pharmacother. 29, 918–921 (1995)
20. Levine, E. G. & Bloomfield, C. D. Semin. Oncol. 19, 47–84 (1992).
21. Magrath, I. et al. J. Clin. Oncol. 14, 925–934 (1996).
22. Burkitt, D. Cancer 20, 756–759 (1967).
23. Fisher, R. I. et al. N. Engl. J. Med. 328,1002–1006 (1993).
24. Fisher, B. et al.. J. Clin. Oncol. 8, 1483–1496 (1990).
25. Fisher, B. et al. J. Clin. Oncol. 19, 931–942 (2001)
26. Rubie, H. et al. Med. Pediatr. Oncol. 36, 247–250 (2001).

Endoxan is a white crystalline powder (monohydrate). It may be used or shipped in solution. Darkens on exposure to light. Odorless

Cytoxan,Mead Johnson,US,1959

An anti-proliferative agent that regulates Bax and Bcl-2 expression.

Oncology

Cyclophosphamide USP is used to treat acute and chronic lymphocytic leukemia; lung cancer; rhabdomyosarcoma; neuroblastoma; ovarian and mammary carcinoma; multiple myeloma; lymphosarcoma; Burkitt’s lymphoma; Hodgkin’s disease; retinoblastoma; mycosis fungoides

Cyclophosphamide (Cytoxan) is the most versatile and useful of the nitrogen mustards. Preclinical testing showed it to have a favorable therapeutic index and to possess the broadest spectrum of antitumor activity of all alkylating agents. As with the other nitrogen mustards, cyclophosphamide administration results in the formation of cross-links within DNA due to a reaction of the two chloroethyl moieties of cyclophosphamide with adjacent nucleotide bases. Cyclophosphamide must be activated metabolically by microsomal enzymes of the cytochrome P450 system before ionization of the chloride atoms and formation of the cyclic ethylenimmonium ion can occur. The metabolites phosphoramide mustard and acrolein are thought to be the ultimate active cytotoxic moiety derived from cyclophosphamide.

ChEBI: Cyclophosphamide is a phosphorodiamide that is 1,3,2-oxazaphosphinan-2-amine 2-oxide substituted by two 2-chloroethyl groups at the amino nitrogen atom. It is an alkylating agent used in the treatment of several forms of cancer including leukemias, lymphomas and breast cancer.

A solution of 7.5 g (0.1 mol) of 1,3-propanolamine and 20.2 g of triethylamine in 100 cc of absolute dioxane is added dropwise at 25°C to 30°C while stirring well to a solution of 25.9 g (0.1 mol) of N,N-bis-(β-chloroethyl)- phosphoric acid amide dichloride in 100 cc of absolute dioxane. After the reaction is complete, the product is separated from the precipitated triethylamine hydrochloride and the filtrate is concentrated by evaporation in waterjet vacuum at 35°C. The residue is dissolved in a large amount of ether and mixed to saturation with water. The N,N-bis-(β-chloroethyl)-N,O-propylene phosphoric acid diamide crystallizes out of the ethereal solution, after it has stood for some time in a refrigerator, in the form of colorless water-soluble crystals. MP 48°C to 49°C. Yield: 65% to 70% of the theoretical.

Cytoxan (Bristol-Myers Squibb); Neosar (Sicor).

Antineoplastic

The Journal of Organic Chemistry, 43, p. 1111, 1978 DOI: 10.1021/jo00400a019

Cyclophosphamide is a fine white crystalline powder. Odorless with a slightly bitter taste. Melting point 41-45 °C. A 2% solution has pH of 4 to 6. Used medicinally as an antineoplastic agent.

Water soluble.

Cyclophosphamide is sensitive to exposure to light (darkens). Also sensitive to oxidation. Aqueous solutions may be kept for a few hours at room temperature, but hydrolysis occurs at temperatures above 86°F. Solutions in DMSO, 95% ethanol or acetone are stable for 24 hours under normal lab conditions. Incompatible with benzyl alcohol. Undergoes both acid and base hydrolysis at extreme pHs

Flash point data for Cyclophosphamide are not available; however, Cyclophosphamide is probably combustible.

cyclophosphamide, an inactive prodrug, is a kind of nitrogen mustard alkylating agent. cyclophosphamide requires enzymatic and chemical activation. as a result, nitrogen mustard is produced. it causes dna cross-linking that accounts for its cytotoxic properties. [1] ic50 of cytotoxicity in mouse embryo balb/c 3t3 cells is 37.6 μm, [2] ic50 of cytotoxicity against human hl60 cells is 8.79 μm measured by mtt assay. [3]cyclophosphamide attaches the alkyl group to the guanine base of dna causing its crosslinking, strand breakage and inducing mutations.[1] emadi a, jones rj, brodsky ra. cyclophosphamide and cancer: golden anniversary. nat rev clin oncol. 2009 nov; 6 (11):638-47.[2] moon ky, kwon ch. n3-methyl-mafosfamide as a chemically stable, alternative prodrug of mafosfamide. bioorg med chem lett. 1998 jul 7; 8 (13):1673-8.[3] patel mm, mali md, patel sk. bernthsen synthesis, antimicrobial activities and cytotoxicity of acridine derivatives. bioorg med chem lett. 2010 nov 1; 20 (21):6324-6.[4] lutsiak me, semnani rt, de pascalis r,et al. inhibition of cd4(+)25+ t regulatory cell function implicated in enhanced immune response by low-dose cyclophosphamide. blood. 2005 apr 1; 105 (7):2862-8. epub 2004 dec 9.[5] chang tk, yu l, maurel p, waxman dj. enhanced cyclophosphamide and ifosfamide activation in primary human hepatocyte cultures: response to cytochrome p-450 inducers and autoinduction by oxazaphosphorines. cancer res. 1997 may 15; 57 (10):1946-54.[6] anderson d, bishop jb, garner rc, et al. cyclophosphamide: review of its mutagenicity for an assessment of potential germ cell risks. mutat res. 1995 aug; 330 (1-2):115-81.

Cyclophosphamide can be given orally, intramuscularly, or intravenously. The plasma half-life of intact cyclophosphamide is 6.5 hours.Only 10 to 15% of the circulating parent drug is protein bound, whereas 50% of the alkylating metabolites are bound to plasma proteins. Since cyclophosphamide and its metabolites are eliminated primarily by the kidneys, renal failure will greatly prolong their retention.
Cyclophosphamide has a wide spectrum of antitumor activity. In lymphomas, it is frequently used in combination with vincristine and prednisone (CVP [or COP] regimen) or as a substitute for mechlorethamine in the MOPP regimen (C-MOPP). High dosages of intravenously administered cyclophosphamide are often curative in Burkitt’s lymphoma, a childhood malignancy with a very fast growth rate.Oral daily dosages are useful for less aggressive tumors, such as nodular lymphomas, myeloma, and chronic leukemias.

Besides being used as an alkylating agent in cancer chemotherapy, cyclophosphamide is a unique drug when used as an immunosuppressant. First, it is the most powerful of all such drugs. Second, it kills proliferating cells, and evidently alkylates a certain region of remaining cells. Finally, its action on T-cells is such that despite its overall suppressive effect, it can, in certain environments, suppress the response of these cells to antigens.
Cyclophosphamide is successfully used for bone transplants. In small doses, it is effective for autoimmune disorders.

The drug is metabolized in the liver and is eliminated via the kidney, with approximately 15% of a given dose being excreted unchanged. Doses should be reduced in patients with levels of creatinine clearance less than 30 mL/min. Interestingly, hepatic dysfunction does not seem to alter metabolism of this drug, but caution should be exercised in patients with inhibited cytochrome P450 (CYP450) enzymes or with a combination of factors that could negatively impact drug activation/inactivation pathways.

Cyclophosphamide is a component of CMF (cyclophosphamide, methotrexate, 5-fluorouracil) and other drug combinations used in the treatment of breast cancer. Cyclophosphamide in combination may produce complete remissions in some patients with ovarian cancer and oat cell (small cell) lung cancer. Other tumors in which beneficial results have been reported include non–oat cell lung cancers, various sarcomas, neuroblastoma, and carcinomas of the testes, cervix, and bladder. Cyclophosphamide also can be employed as an alternative to azathioprine in suppressing immunological rejection of transplant organs.

Chloroacetaldehyde toxicity is accompanied by glutathione depletion, indicating that, as expected, this electrophilic by-product alkylates Cys residues of critical cell proteins. Alkylation of Lys, adenosine, and cytidine residues also is possible. The CYP-generated carbinolamine undergoes nonenzymatic hydrolysis to provide the aldophosphamide either in the bloodstream or inside the cell. If this hydrolysis occurs extracellularly, the aldophosphamide is still able to penetrate cell membranes to reach the intracellular space. Once inside the cell, acrolein (a highly reactive α,β-unsaturated aldehyde) splits off, generating phosphoramide mustard. With a pKa of 4.75, the mustard will be persistently anionic at intracellular pH and trapped inside the cell.

Confirmed human carcinogen producing leukemia, Hodgkin's dsease, gastrointestinal and bladder tumors. Experimental carcinogenic, neoplas tigenic, and teratogenic data. A human poison by ingestion and many other routes. Human systemic effects: hdney changes (hepatic dysfunction), leukopenia (reduced white blood cell count), nausea and alopecia (loss of hair), liver changes, agranulocytosis. Human reproductive and teratogenic effects by multiple routes: spermatogenesis, testicular changes, epiddymis and sperm duct changes, menstrual cycle changes, fetal developmental abnormahties of the craniofacial area, musculoskeletal and cardiovascular systems. Experimental reproductive effects. Human mutation data reported. A powerful skin irritant. Used as an immunosuppressive agent in nonmalignant diseases. When heated to decomposition it emits hghly toxic fumes of PO,, NOx, and Cl-.

Cyclophosphamide, 2-[bis-(2-chloroethyl)amino]tetrahydro- 2H-1,3,2-oxazaphosphorin-2-oxide (30.2.1.15), is made by reacting bis(2-chloroethyl)amine with phosphorous oxychloride, giving N,N-bis-(2-chloroethyl)dichlorophosphoramide (30.2.1.14), which upon subsequent reaction with 3-aminopropanol is transformed into cyclophosphamide (30.2.1.15).

Exodan is used as an immunosuppressive agent in nonmalignant diseases; treatment of malignant lymphoma, multiple meyloma; leukemias, and other malignant diseases. Exodan has been tested as an insect chemosterilant and for use in the chemical shearing of sheep. Exodan is not produced in the United States.; manufactured in Germany and imported into the United States since1959. The FDA estimates that 200,000
300,000 patients per year are treated with exodan. It is administered orally and through injection. The adult dosage is usually 1
5 mg/kg of body weight daily or 10
15 mg/kg administered intravenous every 7
10 days

In veterinary medicine, cyclophosphamide is used primarily in small animals (dogs and cats) in combination with other agents both as an antineoplastic agent (lymphomas, leukemias, carcinomas, and sarcomas) and as an immunosuppressant (SLE, ITP, IMHA, pemphigus, rheumatoid arthritis, proliferative urethritis, etc.). Its use in treating acute immune-mediated hemolytic anemia is controversial;there is some evidence that it does not add beneficial effects when used with prednisone.
Cyclophosphamide has been used as a chemical shearing agent in sheep.

cyclophosphamide has a dose-dependent, bimodal effect on the immune system. low-dose cyclophosphamide not only decreases cell number but leads to decreased functionality of regulatory t cells (tregs). cyclophosphamide treatment enhances apoptosis and decreases homeostatic proliferation of these cells. expression of gitr and foxp3, which are involved in the suppressive activity of tregs, is down-regulated after cyclophosphamide administration.[4] in primary human hepatocyte cultures, cyclophosphamide increases cyp3a4, cyp2c8, and cyp2c9 protein levels, causing its 4-hydroxylation rate enhance.[5] in somatic cells, cyclophosphamide produces gene mutations, chromosome aberrations, micronuclei and sister chromatid exchanges in a variety of cultured cells in the presence of metabolic activation as well as sister chromatid exchanges without metabolic activation. [6]

it has produced chromosome damage and micronuclei in rats, mice and chinese hamsters, and gene mutations in the mouse spot test and in the transgenic lacz construct of muta™mouse. [6]

Potentially hazardous interactions with other drugs
Antipsychotics: avoid with clozapine, increased risk of agranulocytosis.
Cytotoxics: increased toxicity with high-dose cyclophosphamide and pentostatin - avoid.

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seekmedical attention immediately. If this chemical contactsthe skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove fromexposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing hasstopped and CPR if heart action has stopped. Transferpromptly to a medical facility. When this chemical hasbeen swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.

Cyclophosphamide is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans.

The initial metabolic step is mediated primarily by CYP2B6 (and, to a much lower extent, by CYP3A4) and involves hydroxylation of the oxazaphosphorine ring to generate a carbinolamine. This hydroxylation reaction must occur before the molecule will be transported into cells. CYP3A4 (but not CYP2B6) also catalyzes an inactivating N-dechloroethylation reaction, which yields highly nephrotoxic and neurotoxic chloroacetaldehyde.

Store at -20°C

UN3464 Organophosphorus compound, solid, toxic, n.o.s, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3249 Medicine, solid, toxic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN1851 Medicine, liquid, toxic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials

Should be protected from exposure to temperatures above 30°C/86°F.

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal