The growth of H295R cells is considerably inhibited by mitotane (1 nM-100 μM; 6 days) [1]. In TαT1 cells, mitotane (10-100 μM; 6 or 48 hours) dramatically enhances caspase 3/7 activity in the range of 60 μM to 80 μM, while decreasing TαT1 cell viability in a time- and dose-dependent manner. Because caspase 3/7 activity was considerably raised from 40 μM to 100 μM by TSH and TSH β-subunit mRNA expression. In a dose-dependent manner, mitotane (1-30 μM; 24 hours; HepG2) stimulates the transcription of the CYP3A4 and CYP2B6 genes [3]. In HepaRG, mitotane (20 and 40 μM; 6 h) dramatically decreased the amount of neutral lipid droplets per cell and also considerably decreased triglycerol-labeled lipid droplets, which in turn decreased PLIN1 and PLIN3 expression levels [4].

Early on after H295R cell seeding, mitotane (440 mg/kg; ip or po, 5 days per week for 7 weeks) dramatically decreases xenograft volume [1].

Cell Proliferation Assay[1]
Cell Types: H295R Cell
Tested Concentrations: 1 nM-100 μM
Incubation Duration: 6 days
Experimental Results: H295R cells Dramatically diminished proliferation with an IC50 of 22.8 μM.

---

Cell viability assay[2]
Cell Types: TαT1 Cell
Tested Concentrations: 10, 40, 60, 80 and 100 μM
Incubation Duration: 6 or 48 hrs (hours)
Experimental Results: No change in cell viability at 10-80 μM, but significant (P < 0.01 ), cell viability diminished (-56%) at 100 μM after 6 hrs (hours) of incubation. Cell viability was not altered at 10-60 μM, whereas at 60 μM (-31%; P < 0.05), 80 μM (-53%; P < 0.01), and 100 μM (-75.5%; P < 0.01) Dramatically diminished. P < 0.01), after 48 hrs (hours) of incubation.

---

RT-PCR[3]
Cell Types: HepaRG cells and human hepatocytes
Tested Concentrations: 0.1, 1, 10, 20, 30 or 40 μM
Incubation Duration: 24 or 48 hrs (hours)
Experimental Results: Increased mRNA levels of CYP3A4 and CYP2B6.

---

Western Blot Analysis[4]
Cell Types: H295R
Tested Concentrations: 20, 40 and 50 μM
Incubation Duration: 6 hrs (hours)
Experimental Results: diminished expression levels of PLIN1 and PLIN3.

Animal/Disease Models: NOD/SCID/γcnull mice (4 weeks old; 6 × 106 H295R cells were inoculated subcutaneously (sc) (sc) into the right flank) [1]
Doses: 440 mg/kg
Route of Administration: ip or po; 5 days a week , continued for 7 weeks.
Experimental Results: At an early time point (day 13) after H295R cell seeding, xenograft volume was Dramatically diminished. The effect of oral mitotane treatment became insignificant on day 20 after H295R cell inoculation, whereas the effect of intraperitonealmitotane continued until day 34.

Absorption, Distribution and Excretion
The bioavailability of mitotane following oral administration is 40%.
Approximately 10% of an administered dose is recovered in the urine as water-soluble metabolites, with a varying amount of metabolite (1%-17%) excreted in the bile.
Mitotane is extensively distributed and found in most tissues in the body. Fat is the primary site of distribution.
Clinical studies indicate that approximately 40% of mitotane is absorbed after oral administration. After daily doses of 5 to 15 g, concentrations of 10 to 90 ug/mL of unchanged drug and 30 to 50 ug/mL of a metabolite are present in the blood. After discontinuation of therapy, plasma concentrations of mitotane are still measurable for 6 to 9 weeks. Although the drug is found in all tissues, fat is the primary site of storage.
Peak plasma mitotane concentrations occur 3-5 hours after a single oral dose of the drug and distribution of the drug between plasma and tissues is complete within 12 hours. In one study in patients with adrenocortical carcinoma who were receiving an oral dosage of 5-15 g of mitotane daily, serum mitotane concentrations were 7-90 ug/mL and serum concentrations of mitotane metabolites were 29-54 ug/mL. Serum concentrations of mitotane and its metabolites appear to plateau after about 8 weeks of continuous mitotane therapy and generally have not appeared to correlate with therapeutic or toxic effects of the drug; however, some data suggest that tumor regression in patients with adrenocortical carcinoma is associated with serum mitotane concentrations greater than 14 ug/mL and that adverse CNS effects are associated with serum concentrations greater than 20 ug/mL.
Mitotane and its metabolites are distributed to essentially all body tissues with fat being the primary storage site; there is no selective accumulation in the adrenals. Following discontinuance of mitotane therapy, persistent plasma concentrations of mitotane and its metabolites are probably caused by their slow release from fat and other tissues. Although unchanged mitotane has not been detected in CSF, small amounts of one mitotane metabolite have been detected in CSF.
It is not known if mitotane or its metabolites cross the placenta or distribute into milk.
For more Absorption, Distribution and Excretion (Complete) data for MITOTANE (11 total), please visit the HSDB record page.

---

Metabolism / Metabolites
Mitotane undergoes extensive metabolism - both hepatic and extrahepatic - and no unchanged parent drug is excreted in the bile or urine. The major circulating metabolite of mitotane is 1,1-(o,p'-dichlorodiphenyl) acetic acid (o,p’-DDA).
In rabbits and in humans, ortho,para'-dichlorodiphenylacetic acid has been identified as major urinary metabolite.../of mitotane/.
With oral dosing of mitotane, metabolites o,p'-dichlorodiphenylacetic acid and its mono- and dihydroxylated derivatives appeared in urine as well as in stools. An unsaturated metabolite, o,p'-DDE was observed in plasma & tissues of man.
Urine samples were obtained from four patients with Cushing syndrome who had been treated with o,p'-DDD. Methyl-thio containing metabolites and other metabolites of o,p'-DDD were detected in the urine samples by gas chromatographic mass spectrometry. These methyl-thio containing metabolites showed smaller peaks in the gas chromatogram than other peaks derived from other metabolites of o,p'-DDD. Although the biological significance of the pathway forming these methyl-thio containing metabolites is not known at the present /time/. ...
Mitotane is metabolized in the liver and other tissues principally to o,p'-dichlorodiphenyl-ethene and -acetate derivatives; small amounts of these derivatives apparently undergo aromatic hydroxylation and glycine conjugation.
For more Metabolism/Metabolites (Complete) data for MITOTANE (6 total), please visit the HSDB record page.
DDD is absorbed in the stomach and intestine, after which it enters the lymphatic system and is carried throughout the body and incorporated into fatty tissues. Metabolism of DDD occurs mainly via cytochrome P-450 enzymes in the liver and kidney. Its metabolites, mainly DDA (bis(p-chlorophenyl) acetic acid), are excreted in the urine. (L85)
Route of Elimination: A variable amount of metabolite (1%-17%) is excreted in the bile and the balance is apparently stored in the tissues.
Half Life: 18-159 days

---

Biological Half-Life
The plasma terminal half-life of mitotane ranges from 18 to 159 days, with a median of 53 days.
Mitotane reportedly has a plasma elimination half-life of 18-159 days.

Toxicity Summary
DDD toxicity occurs via at least four mechanisms, possibly all functioning simultaneously. DDD reduces potassium transport across the membrane. DDD inhibits the inactivation of voltaged-gated sodium channels. The channels activate (open) normally but are inactivated (closed) slowly, thus interfering with the active transport of sodium out of the nerve axon during repolarization and resulting in a state of hyperexcitability. DDD inhibits neuronal adenosine triphosphatases (ATPases), particularly Na+K+-ATPase, and Ca2+-ATPase which play vital roles in neuronal repolarization. DDD also inhibits the ability of calmodulin, a calcium mediator in nerves, to transport calcium ions that are essential for the release of neurotransmitters. All these inhibited functions reduce the rate of depolarization and increase the sensitivity of neurons to small stimuli that would not elicit a response in a fully depolarized neuron. DDD is also believed to adversely affect the reproductive system by mimicking endogenous hormones and binding to the estrogen and adrogen receptors. (T10, L85)

---

Hepatotoxicity
Serum aminotransferase elevations occur in up to half of patients on conventional doses of mitotane therapy, but elevations above 5 times the upper limit of normal are uncommon (
Likelihood score: E* (unproven but suspected rare cause of clinically apparent liver injury).

---

Protein Binding
6%

---

Toxicity Data
LD50: 113 mg/kg (Oral, Rat) (L138)

---

Interactions
Higher dosage /of adrenocorticoids, glucocorticoid and mineralocorticoid/ may be required to treat adrenal insufficiency since mitotane alters metabolism.
Concurrent use /of central nervous system depression producing medications with mitotane/ may produce additive central nervous system depressant effects.
Mitotane may inhibit the adrenal response to corticotropin; this may interfere with the therapeutic response to corticotropin.
Mitotane has been reported to accelerate the metabolism of warfarin by the mechanism of hepatic microsomal enzyme induction, leading to an increase in dosage requirements for warfarin. Therefore, physicians should closely monitor patients for a change in anticoagulant dosage requirements when administering mitotane to patients on coumarin-type anticoagulants. In addition, mitotane should be given with caution to patients receiving other drugs susceptible to the influence of hepatic enzyme induction.

[1]. Doghman M, et al. Lack of long-lasting effects of mitotane adjuvant therapy in a mouse xenograft model of adrenocortical carcinoma. Mol Cell Endocrinol. 2013 Dec 5;381(1-2):66-9.
[2]. Zatelli MC, et al. Therapeutic concentrations of mitotane (o,p'-DDD) inhibit thyrotroph cell viability and TSH expression and secretion in a mouse cell line model. Endocrinology. 2010 Jun;151(6):2453-61.
[3]. Takeshita A, Igarashi-Migitaka J, Koibuchi N, Mitotane induces CYP3A4 expression via activation of the steroid and xenobiotic receptor. J Endocrinol. 2013 Feb 15;216(3):297-305.
[4]. Warde KM, et al. Mitotane Targets Lipid Droplets to Induce Lipolysis in Adrenocortical Carcinoma. Endocrinology. 2022 Sep 1;163(9):bqac102.

Therapeutic Uses
Antineoplastic Agents, Hormonal
Mitotane is indicated in the treatment of inoperable adrenal cortical carcinoma of both functional and nonfunctional types. /Included in US product label/
Mitotane is also used in the treatment of Cushing's syndrome. /Not included in US or Canadian product labeling/
The effect of mitotane therapy in treatment of adrenocortical carcinoma was studied in 88 patients (mean age 46 yr); 80 of these patients underwent surgery and 59 also received oral mitotane capsule, at a mean initial dose of 10 g/day and a mean maintenance dose of 7 g/day for a mean duration of 10.5 months. The median disease free interval after surgery was 12.1 months. Tumor dissemination occurred in 82% of the patients, most commonly to the lung, liver and adjacent organs. The median survival time was 14.5 months, and the 5 yr survival was 22%. Age over 40 yr and the presence of metastases at the time of diagnosis were the only factors recognized as indicating a poor prognosis. Mitotane controlled hormonal secretion in 75% of the patients. Eight mitotane treated patients had partial tumor regression, but the drug did not have a significant effect on survival. It was concluded that adrenocortical carcinoma carries a poor prognosis; mitotane therapy may offer transient benefits, particularly in controlling endocrine symptoms.

---

Drug Warnings
/BOXED WARNING/ WARNINGS: Lysodren (mitotane tablets, USP) should be administered under the supervision of a qualified physician experienced in the uses of cancer chemotherapeutic agents. Lysodren should be temporarily discontinued immediately following shock or severe trauma since adrenal suppression is its prime action. Exogenous steroids should be administered in such circumstances, since the depressed adrenal may not immediately start to secrete steroids.
... Seventeen consecutive patients who were treated with mitotane after radical resection of adrenocortical cancer (ACC) from 1999 to 2005 underwent physical examination, routine laboratory evaluation, monitoring of mitotane concentrations, and a hormonal work-up at baseline and every 3 months till ACC relapse or study end (December 2007). Mitotane toxicity was graded using NCI CTCAE criteria. All biochemical measurements were performed at our center and plasma mitotane was measured by an in-house HPLC assay. All the patients reached mitotane concentrations >14 mg/L and none of them discontinued definitively mitotane for toxicity; 14 patients maintained consistently elevated mitotane concentrations despite tapering of the drug. Side effects occurred in all patients but were manageable with palliative treatment and adjustment of hormone replacement therapy. Mitotane affected adrenal steroidogenesis with a more remarkable inhibition of cortisol and DHEAS than aldosterone. Mitotane induced either perturbation of thyroid function mimicking central hypothyroidism or, in male patients, inhibition of testosterone secretion. The discrepancy between salivary and serum cortisol, as well as between total and free testosterone, is due to the mitotane-induced increase in hormone-binding proteins which complicates interpretation of hormone measurements. ...
/Investigators/ prospectively studied 7 patients with adrenocortical cancer on mitotane therapy. Before and 1 and 2 or more weeks after starting mitotane we determined the platelet counts, bleeding times and global coagulation parameters. All patients had a normal bleeding time before treatment. In 6 cases the bleeding time became prolonged (245-555 s). Four patients exhibited platelet aggregation responses compatible with an aspirin-like defect. It is concluded that mitotane may cause a clinically relevant defect of platelet function.
Gastrointestinal disturbances (anorexia, nausea, vomiting, and diarrhea) occur in 80% of patients and are usually dose limiting. About 40% of patients experience central nervous system side effects (lethargy and somnolence, 25%; dizziness or vertigo, 15%). About 15% of patients develop dermatitis.
For more Drug Warnings (Complete) data for MITOTANE (28 total), please visit the HSDB record page.

---

Pharmacodynamics
The administration of mitotane alters the peripheral metabolism of steroids, leading to a reduction in plasma 17-hydroxycorticosteroids and an increase in 6-β-hydroxycortisol in addition to normal corticosteroid levels.

C14H10CL4

320.0412

317.953

53-19-0

Mitotane-13C6;1261396-21-7;Mitotane-d8;2673270-14-7

4211

Crystals from pentane or methanol

1.4±0.1 g/cm3

398.9±37.0 °C at 760 mmHg

77-78 °C(lit.)

194.2±23.9 °C

0.0±0.9 mmHg at 25°C

1.599

5.39

0

0

3

18

248

0

ClC([H])(C([H])(C1=C([H])C([H])=C([H])C([H])=C1Cl)C1C([H])=C([H])C(=C([H])C=1[H])Cl)Cl

JWBOIMRXGHLCPP-UHFFFAOYSA-N

InChI=1S/C14H10Cl4/c15-10-7-5-9(6-8-10)13(14(17)18)11-3-1-2-4-12(11)16/h1-8,13-14H

1-chloro-2-[2,2-dichloro-1-(4-chlorophenyl)ethyl]benzene

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 100 mg/mL (~312.46 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.81 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 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL 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: 2.5 mg/mL (7.81 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 2.5 mg/mL (7.81 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 25.0 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.)