GnRHR

Degarelix, among the LHRH antagonists Cetrorelix (HY-P0009), Abarelix (HY-13534), and Ganirelix (HY-P1628), exhibits the least amount of histamine release and the weakest histamine-releasing properties[1]. Except for PC-3 cells, degarelix (1 nM-10 μM, 0-72 h) decreases cell viability in all prostate cell lines (WPE1-NA22, WPMY-1, BPH-1, and VCaP cells)[2].
Degarelix (10 μM, 0-72 h) uses apoptosis to directly affect the growth of prostate cells[2].

Degarelix (0-10 μg/kg; s.c.; once) reduces plasma levels of testosterone and LH in castrated rats in a dose-dependent manner[3].
Degarelix is stable when incubated in microsomes and cryopreserved hepatocytes from animal liver tissue. In rats and dogs, the majority of the degarelix dosage is excreted in the urine and feces in equal proportions (40–50% in each matrix) within 48 hours, while in monkeys, the main excretion routes are the feces (50%) and the kidneys (22%)[4].

Male Sprague-Dawley rats, castrated
0.3, 1, 3 and 10 μg/kg or 12.5, 50, and 200 μg/kg
Subcutaneous injection, once

Absorption, Distribution and Excretion
Degarelix forms a depot at the site of injection after subcutaneous administration from which the drug slowly released into circulation. After a single bolus dose of 2mg/kg, peak plasma concentrations of degarelix occured within 6 hours at a concentration of 330 ng/mL. Ki = 0.082 ng/mL and 93% of receptors were fully suppressed; MRT = 4.5 days.
Fecal (70% to 80%) and renal (20%-30% of unchanged drug)
Central compartment: 8.88 - 11.4 L; Peripheral compartment: 40.9 L
Following subcutaneous administration of degarelix to prostate cancer patients the clearance is approximately 9 L/hr.
The protein binding in plasma of mouse, rat, dog, monkey, and humans was measured using the (3)H-degarelix and the ultracentrifugation technique. The plasma binding was approximately 90% in animals and humans. Distribution of radioactivity following administration of (3)H-degarelix was studied in rats, dogs and monkeys, doses were respectively 0.03 mg/kg, 0.003 mg/kg and 0.0082 mg/kg. Radioactivity of tissues was measured after sacrifice and necropsy of the animals. High concentrations were mainly seen at the s.c. injection site and in organs of excretion. Lower concentrations, but still higher than those in plasma were generally seen in some organs of the endocrine and reproductive systems most of which contain specific receptors for LHRH, and organs rich in reticuloendothelial cells during the elimination phase. There was no indication of tissue retention.
Balance of the radioactivity following SC administration of (3)H-degarelix was studied in rats, dogs and monkeys. Degarelix was mainly excreted unchanged via the urine and was subject to sequential peptidic degradation during its elimination via the hepato-biliary pathway in both animals and man.
After subcutaneous administration, degarelix forms a local depot at the injection site, leading to retarded and extended release of the active drug. The release from the depot is dependent on the concentration in the dose formulation and the dose volume. Furthermore, in repeat dose studies, increasing concentrations in the dose formulation resulted in sub-proportional increases in maximum plasma concentration (Cmax) and area under plasma concentration vs time in the dosing interval (AUC), an increase in trough plasma concentration (Ctrough), an increase in terminal half-life (t1/2), thus increasing the time to reach steady state, and a tendency of increase in time to maximum plasma concentration (Tmax).
Degarelix forms a depot at the injection site following subcutaneous administration from which the drug is very slowly released into circulation. Peak plasma concentrations of degarelix generally occur within 2 days following subcutaneous administration of a single 240 mg dose at a concentration of 40 mg/mL.. The pharmacokinetic behavior of degarelix is strongly influenced by its concentration in the injection solution. Approximately 90% of the drug is bound to plasma proteins. No quantitatively substantial metabolites have been detected in plasma following subcutaneous adminstration. Degarelix does not appear to be a substrate, inducer, or inhibitor of the cytochrome P-450 (CYP) enzyme or P-glycoprotein transport systems based on in vitro studies. Degarelix is eliminated in a biphasic manner, with a median terminal half-life of about 53 days following subcutaneous administration of a 240 mg dose at a concentration of 40 mg/mL in prostate cancer patients. Degarelix is subject to peptide hydrolysis during its passage through the hepatobiliary system and is mainly excreted as peptide fragments in feces. Approximately 20-30% of a given dose of degarelix is renally eliminated, suggesting that approximately 70-80% is excreted via the hepatobiliary system.
For more Absorption, Distribution and Excretion (Complete) data for Degarelix (6 total), please visit the HSDB record page.

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Metabolism / Metabolites
70% - 80% of degarelix is subject to peptide hydrolysis during its passage through the hepatobiliary system and then fecally eliminated. No active or inactive metabolites or involvement of CYP450 isozymes.
The stability of degarelix was studied in liver microsomes from males in rat, guinea pig, rabbit, dog, monkey, and human, for up to 60 min. No degradation of degarelix was detected in liver microsomes from rabbit, dog, monkey, and human. Tendency to minor degradation of degarelix was seen in liver microsomes from guinea pig and rat. The in vitro metabolism of degarelix was further investigated in human liver microsomes for up to 60 min. The metabolism pattern of degarelix was reported to be similar in humans and animals. Degarelix was virtually no substrate for oxidative metabolism, but was degraded by peptidases with generation of various truncated peptides. Only low concentration of one metabolite was seen in human plasma, and this metabolite was also seen in rats, dogs and monkeys.

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Biological Half-Life
Terminal half-life: 41.5 - 70.2 days; Absorption half-life: 32.9 hours; Half-life from injection site: 1.17 days.
Degarelix is eliminated in a biphasic manner, with a median terminal half-life of about 53 days following subcutaneous administration of a 240 mg dose at a concentration of 40 mg/mL in prostate cancer patients.

Hepatotoxicity
Degarelix therapy has been associated with serum enzyme elevations in up to one-third of patients. The elevations, however, are generally mild and self-limited, resolving even without dose adjustment. ALT values above 3 times the ULN occur in less than 1% of patients. Occasional patients require drug discontinuation because of serum enzyme elevations, but no instances of liver injury with jaundice or clinically apparent acute liver injury were reported in the initial clinical trials of degarelix. Since its approval and more widescale use, there have been no published reports of clinically apparent liver injury attributed to degarelix, although its general use has been limited.
Likelihood score: E (unlikely cause of clinically apparent liver injury).

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Protein Binding
90% of the drug is bound to plasma proteins.

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Interactions
Since androgen deprivation treatment may prolong the QTc interval, the concomitant use of degarelix with medicinal products known to prolong the QTc interval or medicinal products able to induce torsades de pointes such as class IA (e.g. quinidine, disopyramide) or class III (e.g. amiodarone, sotalol, dofetilide, ibutilide) antiarrhythmic medicinal products, methadone, cisapride, moxifloxacine, antipsychotics, etc. should be carefully evaluated.

[1]. An update on the use of degarelix in the treatment of advanced hormone-dependent prostate cancer. Onco Targets Ther. 2013 Apr 16;6:391-402.

[2]. In search of the molecular mechanisms mediating the inhibitory effect of the GnRH antagonistdegarelix on human prostate cell growth. PLoS One. 2015 Mar 26;10(3):e0120670.

[3]. Pharmacological profile of a new, potent, and long-acting gonadotropin-releasing hormoneantagonist: degarelix. J Pharmacol Exp Ther. 2002 Apr;301(1):95-102.

[4]. Metabolite profiles of degarelix, a new gonadotropin-releasing hormone receptor antagonist, in rat, dog, and monkey. Drug Metab Dispos. 2011 Oct;39(10):1895-903.

Therapeutic Uses
Degarelix is used for the treatment of advanced prostate cancer. /Use included in US product label/

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Drug Warnings
Degarelix is contraindicated in women who are or may become pregnant. Degarelix can cause fetal harm when administered to a pregnant woman.
FDA Pregnancy Risk Category: X /CONTRAINDICATED IN PREGNANCY. Studies in animals or humans, or investigational or post-marketing reports, have demonstrated positive evidence of fetal abnormalities or risk which clearly outweights any possible benefit to the patient./
The most frequently reported adverse reactions at the injection sites were pain (28%), erythema (17%), swelling (6%), induration (4%) and nodule (3%). These adverse reactions were mostly transient, of mild to moderate intensity, occurred primarily with the starting dose and led to few discontinuations (<1%). Grade 3 injection site reactions occurred in 2% or less of patients receiving degarelix.
A total of 1325 patients with prostate cancer received Firmagon either as a monthly treatment (60-160 mg) or as a single dose (up to 320 mg). A total of 1032 patients (78%) were treated for at least 6 months and 853 patients (64%) were treated for one year or more. The most commonly observed adverse reactions during Firmagon therapy included injection site reactions (e.g. pain, erythema, swelling or induration), hot flashes, increased weight, fatigue, and increases in serum levels of transaminases and gammaglutamyltransferase (GGT). The majority of the adverse reactions were Grade 1 or 2, with Grade 3/4 adverse reaction incidences of 1% or less.
For more Drug Warnings (Complete) data for Degarelix (15 total), please visit the HSDB record page.

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Pharmacodynamics
Degarelix is a synthetic derivative of GnRH decapeptide, the ligand of the GnRH receptor. Gonadotropin and androgen production result from the binding of endogenous GnRH to the GnRH receptor. Degarelix antagonizes the GnRH receptor which in turn blocks the release of LH and FSH from the pituitary. LF and FSH decreases in a concentration-dependent manner. The reduction in LH leads to a decrease in testosterone release from the testes.

C₈₂H₁₀₃CLN₁₈O₁₆

1632.26

1630.748

C, 60.34; H, 6.36; Cl, 2.17; N, 15.45; O, 15.68

214766-78-6

Degarelix-d7; Degarelix acetate hydrate; 934246-14-7;214766-78-6;Degarelix-d7;934016-19-0

16136245

White to off-white solid powder

1.3±0.1 g/cm3

1.620

4.45

17

18

41

117

3390

11

C[C@H](C(N)=O)NC([C@H]1N(C([C@H](CCCCNC(C)C)NC([C@H](CC(C)C)NC([C@@H](CC2=CC=C(NC(N)=O)C=C2)NC([C@H](CC3=CC=C(NC([C@H](CC(N4)=O)NC4=O)=O)C=C3)NC([C@H](CO)NC([C@@H](CC5=CC=CN=C5)NC([C@@H](CC6=CC=C(Cl)C=C6)NC([C@@H](CC7=CC=C8C=CC=CC8=C7)NC(C)=O)=O)=O)=O)=O)=O)=O)=O)=O)CCC1)=O

MEUCPCLKGZSHTA-XYAYPHGZSA-N

InChI=1S/C82H103ClN18O16/c1-45(2)35-60(72(107)92-59(16-9-10-33-87-46(3)4)80(115)101-34-12-17-68(101)79(114)88-47(5)70(84)105)93-74(109)63(38-51-23-30-58(31-24-51)91-81(85)116)95-76(111)64(39-50-21-28-57(29-22-50)90-71(106)66-42-69(104)100-82(117)99-66)97-78(113)67(44-102)98-77(112)65(41-53-13-11-32-86-43-53)96-75(110)62(37-49-19-26-56(83)27-20-49)94-73(108)61(89-48(6)103)40-52-18-25-54-14-7-8-15-55(54)36-52/h7-8,11,13-15,18-32,36,43,45-47,59-68,87,102H,9-10,12,16-17,33-35,37-42,44H2,1-6H3,(H2,84,105)(H,88,114)(H,89,103)(H,90,106)(H,92,107)(H,93,109)(H,94,108)(H,95,111)(H,96,110)(H,97,113)(H,98,112)(H3,85,91,116)(H2,99,100,104,117)/t47-,59+,60+,61-,62-,63-,64+,65-,66+,67+,68+/m1/s1

(4S)-N-[4-[(2S)-2-[[(2S)-2-[[(2R)-2-[[(2R)-2-[[(2R)-2-acetamido-3-naphthalen-2-ylpropanoyl]amino]-3-(4-chlorophenyl)propanoyl]amino]-3-pyridin-3-ylpropanoyl]amino]-3-hydroxypropanoyl]amino]-3-[[(2R)-1-[[(2S)-1-[[(2S)-1-[(2S)-2-[[(2R)-1-amino-1-oxopropan-2-yl]carbamoyl]pyrrolidin-1-yl]-1-oxo-6-(propan-2-ylamino)hexan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-[4-(carbamoylamino)phenyl]-1-oxopropan-2-yl]amino]-3-oxopropyl]phenyl]-2,6-dioxo-1,3-diazinane-4-carboxamide

Degarelix Free Base; HSDB 7817; HSDB7817; HSDB-7817

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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

DMSO: ~10 mg/mL (~6.1 mM)
H2O: ~5 mg/mL (~3.1 mM)

Solubility in Formulation 1: ≥ 1 mg/mL (0.61 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 10.0 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.

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Solubility in Formulation 2: ≥ 1 mg/mL (0.61 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 10.0 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.

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Solubility in Formulation 3: ≥ 1 mg/mL (0.61 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 10.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)