Altretamine (also known as Hexamethylmelamine, NSC13875, ENT50852, WR-95704) is an alkylating anticancer drug which also acts as a chemosterilant for male houseflies and other insects. In 1990, the FDA in the United States approved altretamine. In patients with persistent or recurrent ovarian cancer, it is indicated for use as a single agent in palliative treatment after first-line therapy with cisplatin and/or alkylating agent-based combination. MeSH classifies altretamine as an alkylating antineoplastic agent, although the exact mechanism by which it carries out its anti-cancer effect remains unclear.

Physicochemical Properties

Molecular Formula	C9H18N6
Molecular Weight	210.28
Exact Mass	210.159
Elemental Analysis	C, 51.41; H, 8.63; N, 39.97
CAS #	645-05-6
Related CAS #	645-05-6
PubChem CID	2123
Appearance	White to off-white solid powder
Density	1.1±0.1 g/cm3
Boiling Point	339.4±25.0 °C at 760 mmHg
Melting Point	171-175 °C(lit.)
Flash Point	159.1±23.2 °C
Vapour Pressure	0.0±0.7 mmHg at 25°C
Index of Refraction	1.610
LogP	2.42
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	3
Heavy Atom Count	15
Complexity	148
Defined Atom Stereocenter Count	0
SMILES	N(C([H])([H])[H])(C([H])([H])[H])C1N=C(N=C(N=1)N(C([H])([H])[H])C([H])([H])[H])N(C([H])([H])[H])C([H])([H])[H]
InChi Key	UUVWYPNAQBNQJQ-UHFFFAOYSA-N
InChi Code	InChI=1S/C9H18N6/c1-13(2)7-10-8(14(3)4)12-9(11-7)15(5)6/h1-6H3
Chemical Name	2-N,2-N,4-N,4-N,6-N,6-N-hexamethyl-1,3,5-triazine-2,4,6-triamine
Synonyms	NSC-13875; ENT-50852; RB-1515; WR-95704; NSC 13875; ENT 50852; RB 1515; WR 95704; NSC13875; ENT50852; RB1515; WR95704; Hexamethylmelamine, Hemel; Hexaloids; Hexalen; Hexastat; Hexinawas; HMM; HXM
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	Altretamine is an antineoplastic agent.[1]
ln Vivo	The anti-tumor impact of MV522 cells can be amplified when used in combination with IrofuLven (100, 133 mg/kg, ip.) [1].
Animal Protocol	Mice: Balb/c nu/nu Female mice, 4 weeks old and weighing 18–22 g, are injected subcutaneously with 8–10 million MV522 cells. Starting on day 10 following tumor implantation, metformin is injected intraperitoneally three times a week for three weeks. Two perpendicular diameters are used to measure tumor size, and the formula w = [(width)2 × length/2] is used to estimate tumor weight (TW). When necessary, altretamine is diluted with 10% DMSO/normal saline after being prepared as stock solutions containing 1–10 mg/mL in 40% DMSO/normal saline[1].
ADME/Pharmacokinetics	Absorption, Distribution and Excretion Human urinary metabolites were Ndemethylated homologues of altretamine with <1% unmetabolized altretamine excreted at 24 hours. Rapidly and well-absorbed following oral administration; however, because of rapid hepatic metabolism, peak plasma concentrations are variable. ... The inter-hand intrapatient variability of the bioavailability of altretamine after oral administration represents an important drawback for effective clinical use of this drug. The variability appears to be mostly related to the first-pass effect and therefore may be overcome by intravenous administration of the drug. Attempts to administer the drug intravenously have not been successful in the past... Because it is highly lipid-soluble, altretamine is distributed to tissues with a high lipid component (e.g., omentum and subcutaneous tissues). Protein binding: Free fractions: Altretamine: 6%; Pentamethylmelamine: 25%; Tetramethylmelamine: 50%. For more Absorption, Distribution and Excretion (Complete) data for ALTRETAMINE (10 total), please visit the HSDB record page. Metabolism / Metabolites Biotransformation /is/ Hepatic. Metabolism is required for activity. Altretamine undergoes rapid and extensive demethylation, catalyzed by cytochrome P450 enzymes. The covalent binding of hexamethylmelamine (HMM) and its metabolites was studied in liver, tumor, blood, kidney, spleen, lung, brain, heart, and small intestine after a single ip injection of 2,4,6-14C-hexamethylmelamine (50 mg/kg) to C57Bl/6J female mice bearing 20-day-old M5076/73A ovarian cancer. ... HMM metabolism was also studied. Tissue distribution of pentamethylmelamine (PMM), 2,2,4,6-tetramethylmelamine (TMM), and 2,4,6-trimethylmelamine (TriMM) was determined at the three times considered. At 2 hr the drug was already extensively metabolized, TriMM being the major metabolite among those determined. ... In all animal species, including humans, altretamine undergoes oxidative N-demethylation with the formation of hydroxymethyl derivatives as intermediates. Hydroxymethylmelamines are believed to be responsible for the cytotoxic and antitumour activity of the drug. ... In the rat 40% of a dose of 25 mg/kg of hexamethylmelamine or pentamethylmelamine was excreted in the urine as metabolites, more than 95% of which were N2N4-dimethylmelamine and monomethylmelamine. Biliary excretion of hexamethylmelamine or pentamethylmelamine and their N-demethylated metabolites accounted for less than 2% of the administered dose. Only 3% was excreted with the feces, suggesting that there is intestinal reabsorption of a portion of the methylmelamines passing into the bile. Conjugates of methylmelamines with glucuronic acid or sulphate were found only in minute quantities in the urine or bile of rats treated with hexamethylmelamine or pentamethylmelamine. However a conjugation product of pentamethylmelamine, of as yet unknown nature, is a major metabolite after pentamethylmelamine treatment. Biological Half-Life 4.7-10.2 hours Elimination /half-life/-Beta-phase: Range, 4.7 to 10.2 hours.
Toxicity/Toxicokinetics	Hepatotoxicity Altretamine therapy is associated with a low rate of serum enzyme elevations, but these are generally mild and self limited, not requiring dose adjustment. Rare instances of clinically apparent acute liver injury attributed to altretamine have been reported, but the clinical features have not been characterized. Altretamine has not been linked specifically to sinusoidal obstruction syndrome, but it is rarely used in high doses in neoplastic disease or in conditioning regimens for bone marrow transplantation, situations in which alkylating agents are commonly associated with this complication. Likelihood score: E* (unlikely but suspected rare cause of liver injury). Protein Binding 94% Toxicity Data Human(po): TDL0 8 mg/kg Rat(po): LD50 350 mg/kg Rat(ip): LD50 265 mg/kg Mouse(po): LD50 437 mg/kg Mouse(ip): LD50 200 mg/kg Mouse(iv): LD50 171 mg/kg Interactions Blood dyscrasia causing medications (leukopenic and/or thrombocytopenic effects of altretamine may be increased with concurrent or recent therapy if these medications cause the same effects; dosage adjustment of altretamine, if necessary, should be based on blood counts) Additive bone marrow depression may occur /with radiation therapy/; dosage reduction may be required when two or more bone marrow depressants, including radiation, are used concurrently or consecutively. Concurrent use of altretamine with monoamine oxidase (MAO) inhibitors, including furazolidone, procarbazine, and selegiline use may result in severe orthostatic hypotension. Because normal defense mechanisms may be suppressed by altretamine therapy, the patient's antibody response to /a killed/ vaccine may be decreased. The interval between discontinuation of medications that cause immunosuppression and restoration of the patient's ability to respond to the vaccine depends on the intensity and type of immunosuppression-causing medication used, the underlying disease, and other factors; estimates vary from 3 months to 1 year) For more Interactions (Complete) data for ALTRETAMINE (6 total), please visit the HSDB record page. Non-Human Toxicity Values LD50 Rat oral 350 mg/kg LD50 Guinea pig oral 255 mg/kg
References	[1]. Synergy of irofulven in combination with other DNA damaging agents: synergistic interaction with altretamine, alkylating, and platinum-derived agents in the MV522 lung tumor model. Cancer Chemother Pharmacol. 2008 Dec;63(1):19-26.
Additional Infomation	Altretamine can cause developmental toxicity and male reproductive toxicity according to state or federal government labeling requirements. Hexamethylmelamine is a colorless crystalline solid. Insoluble in water. (NTP, 1992) Hexamethylmelamine is a triamino-1,3,5-triazine. An alkylating agent proposed as an antineoplastic. It also acts as a chemosterilant for male houseflies and other insects. Altretamine is an Alkylating Drug. The mechanism of action of altretamine is as an Alkylating Activity. Altretamine is an orally administered alkylating agent, formerly known as hexamethylmelamine, which is currently used as a secondary therapy for advanced ovarian carcinoma. Altretamine therapy has been associated with low rates of serum enzyme elevations during therapy and with rare instances of acute, clinically apparent injury. Altretamine is a synthetic cytotoxic s-triazine derivative similar in structure to alkylating agent triethylenemelamin with antineoplastic activity. Although the precise mechanism by which altretamine exerts its cytotoxic effect is unknown, N-demethylation of altretamine may produce reactive intermediates which covalently bind to DNA, resulting in DNA damage. (NCI04) A hexamethyl-2,4,6-triamine derivative of 1,3,5-triazine. Drug Indication For use as a single agent in the palliative treatment of patients with persistent or recurrent ovarian cancer following first-line therapy with a cisplatin and/or alkylating agent-based combination. Mechanism of Action The precise mechanism by which altretamine exerts its cytotoxic effect is unknown although it is classified as an alkylating anti-neoplastic agent. Through this mechanism, the drug is metabolized into alkylating agents by N-demethylation. These alkylating species consequently damage tumor cells. The exact mechanism of action is unknown. Although altretamine structurally resembles an alkylating agent, it has not been found to have alkylating activity in vitro. There is some evidence that it may inhibit DNA and RNA synthesis. The hexamethylmelamine analogue trimelamol (tris-hydroxymethyl[trimethyl]melamine) and its equicytotoxic stable analogues CB 7547, CB 7639 and CB 7669 have been used to clarify the mechanism of action for the N-(hydroxymethyl)melamines as antitumour agents. Two main mechanisms have been proposed and explored: (i) formation of a reactive iminium species forming covalent adducts with DNA; and (ii) local formaldehyde release leading to cytotoxic damage. 32P-postlabelling and thermal denaturation experiments showed these compounds to be interactive with cytosine and guanine. Trimelamol gave rise to DNA-interstrand crosslinks in naked plasmid DNA and in cultured cell lines, whereas the analogues failed to do so under a variety of experimental conditions. Along with our observations that cell lines with acquired resistance to the N-(hydroxymethyl)melamines showed no significant cross-resistance to classical bifunctional alkylating agents, DNA crosslinking may play only a minor role in their mechanism of action. In cultured cell lines treatment with formaldehyde, trimelamol and CB 7639 gave rise to high levels of DNA-protein crosslinks with a gradual disappearance over a 24 hr period. Along with ... earlier observations that resistance to trimelamol coincides with cross-resistance to formaldehyde, /investigators/ conclude that formaldehyde-release may be an important factor in their cytotoxicity. Further, the cytotoxicity of trimelamol or formaldehyde towards human ovarian cancer cells was not influenced by glutathione depletion. /N-(hydroxymethyl)melamines/ Therapeutic Uses Antineoplastic Altretamine is indicated for use as a single agent in the palliative treatment of patients with persistent or recurrent epithelial ovarian cancer following first-line therapy with a cisplatin- and/or alkylating agent-based combination. /Included in US product label/ Altretamine, in combination therapy, is considered reasonable medical therapy at some point in the management of small cell lung carcinoma (Evidence rating: IA). /Not included in US product label/ Drug Warnings Secondary malignancies are potential delayed effects of many antineoplastic agents, although it is not clear whether the effect is related to their mutagenic or immunosuppressive action. The effect of dose and duration of therapy is also unknown, although risk seems to increase with long-term use. Although information is limited, available data seem to indicate that the carcinogenic risk is greatest with the alkylating agents. The bone marrow depressant effects of altretamine may result in an increased incidence of microbial infection, delayed healing, and gingival bleeding. Dental work, whenever possible, should be completed prior to initiation of therapy or deferred until blood counts have returned to normal. Patients should be instructed in proper oral hygiene during treatment, including caution in use of regular toothbrushes, dental floss, and toothpicks. Adverse events ... indicating the need for medical attention /occurring/ at an incidence more frequent: Anemia (unusual tiredness); leukopenia (fever or chills; cough or hoarseness; lower back or side pain; painful or difficult urination); neurotoxicity, including central nervous system (CNS) effects (anxiety; clumsiness; confusion; dizziness; mental depression; weakness; seizures); neurotoxicity, including peripheral neuropathy (numbness in arms or legs); thrombocytopenia (unusual bleeding or bruising; black, tarry stools; blood in urine or stools; pinpoint red spots on skin). Incidence /occurring/ rarely Hepatotoxicity; skin rash or itching. /Altretamine is/ contraindicated in patients with known sensitivity to altretamine. For more Drug Warnings (Complete) data for ALTRETAMINE (11 total), please visit the HSDB record page. Pharmacodynamics Altretamine is a novel antineoplastic agent. The precise mechanism by which altretamine exerts its cytotoxic effect is unknown, although a number of theoretical possibilities have been studied. Structurally, altretamine resembles the alkylating agent triethylenemelamine, yet in vitro tests for alkylating activity of altretamine and its metabolitics have been negative. Altretamine has been demonstrated to be efficacious for certain ovarian tumors resistant to classical alkylating agents. Metabolism of altretamine is a requirement of cytotoxicity. Synthetic monohydroxymethylmelamines, and products of altretamine metabolism, in vitro and in vivo, can form covalent adducts with tissue macromolecules including DNA, but the relevance of these reactions to antitumor activity is unknown.

Solubility Data

Solubility (In Vitro)

DMSO: 8.3~15 mg/mL (39.6~71.3 mM) Water: <1 mg/mL Ethanol: ~33 mg/mL (~156.9 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 0.83 mg/mL (3.95 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 8.3 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 0.83 mg/mL (3.95 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 8.3 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	4.7556 mL	23.7778 mL	47.5556 mL
	5 mM	0.9511 mL	4.7556 mL	9.5111 mL
	10 mM	0.4756 mL	2.3778 mL	4.7556 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.