Levoketoconazole: a novel treatment for endogenous Cushing's syndrome

Figures & data

Figure 1. Chemical structure of levoketoconazole [32]

Table 1. Calculated IC₅₀ values and spectral binding constants for ketoconazole enantiomers and its racemate toward different human steroidogenic P450 enzymes [33]

Enzyme	Levoketoconazole (2S, 4R isomer)	Dextroketoconazole (2R, 4S isomer)	Ketoconazole (racemic compound)
IC50 value, nmol/L
CYP11A1	1450	25,100	2270
CYP17A1	28	596	58
CYP11B1	52	1370	139
CYP11B2	150	472	176
Spectral binding constant (KS), nmol, mean ± SD
CYP11A1	840 ± 50	3030 ± 710	940 ± 210
CYP17A1	110 ± 10	220 ± 0	190 ± 0
CYP11B1	140 ± 10	200 ± 10	150 ± 60

IC₅₀: half maximal inhibitory concentration; SD: standard deviation.

Figure 2. Levoketoconazole inhibition of cortisol synthesis. Gray boxes depict the relative potency of levoketoconazole versus ketoconazole based on half maximal inhibitory concentration (IC₅₀) values from an in vitro study using HEK-293 or V79 cell lines stably expressing human steroidogenic P450 enzymes [33]

Table 2. Levoketoconazole pharmacokinetic studies

Study	Associated citation	Study design	Participants	Treatment	Key findings	Safety
Food effect study COR-2017-02	N/A	Randomized, open-label, single-dose, 2-period, 2-sequence cross-over study 7-d washout period	Healthy volunteers (N = 24) Age range: 18–53 y	Levoketoconazole 600 mg single dose Fasted or fed (standard high-fat meal)	Cmax unchanged with food (GSLM ratio of fed vs. fasted: 99.6% [90% CI: 86.6%, 114.6%]) AUC0-last increased ~30% with food (GSLM ratio of fed vs. fasted: 130% [90% CI: 110%, 153%]) Tmax delayed ~2 h with food (median Tmax [fed vs. fasted]: 4 h vs. 2 h)	AEs (>1 participant): headache (fed vs. fasted): 12 (50.0%) vs. 11 (50.0%); abnormal hepatic function*: 2 (8.3%) vs. 0%; nausea: 0% vs. 2 (9.1%); vomiting: 2 (8.3%) vs. 0%
Felodipine DDI study (AA34509)	Thieroff-Ekerdt RI, Mould DR. 18th European Congress of Endocrinology (ECE); 28 May 2016–31 May 2016; Munich, Germany [45].	Randomized, placebo-controlled, 2-period cross-over study	Healthy volunteers (N = 18) Age range: 18–55 y	Levoketoconazole 400 mg qd or placebo for 8 d Felodipine 5 mg single dose on day 5	Data not adequate for accurate estimation of levoketoconazole PK parameters Felodipine Cmax and AUC0-inf increased ~10-fold with levoketoconazole vs. placebo (LSM ratio: Cmax, 937.1% [90% CI: 757.9%, 1158.8%], AUC0-inf, 1007.3% [90% CI: 86.8%, 1167.9%]) Felodipine median Tmax increased with levoketoconazole vs. placebo: 4.25 h vs. 3.25 h Felodipine mean t1/2 with levoketoconazole vs. placebo: 43.1 h vs. 25.7 h	AEs (>25% of participants, levoketoconazole + felodipine vs. placebo + felodipine): headache: 100% vs. 38.9%; nausea: 52.9% vs. 5.6%; dizziness: 35.3% vs. 22.2%
Atorvastatin DDI study (AA34510)	Thieroff-Ekerdt R, Lavin P, Abou-Gharbia M, France NP. Endocr Rev. 2016;37(2 suppl) [34]. Boudriau S, Demnati R, Swearingen D, et al. American Society of Clinical Pharmacology and Therapeutics (ASCPT); 2 April 2008–5 April 2008; Orlando, FL [44].	Randomized, placebo-controlled, 3-period crossover study	Healthy volunteers (N = 24) Age range: 18–55 y	Levoketoconazole 400 mg qd, ketoconazole 400 mg qd, or placebo for 7 d Atorvastatin 80 mg single dose on day 5	Levoketoconazole Cmax: 11.1 μg/mL and AUC: 114 μg/mL* h after 5 d of levoketoconazole with a single dose of atorvastatin After 5 d of racemic ketoconazole with a single dose of atorvastatin, Cmax (6.1 vs. 2.0 μg/mL) and AUC (61.1 vs. 20.4 μg/mL* h) of levoketoconazole were 3-fold higher than the 2R,4S enantiomer Atorvastatin AUC increased by 28% and 52% when coadministered with levoketoconazole and ketoconazole, respectively; however, Cmax was lower when coadministered with either levoketoconazole or ketoconazole at steady state Prior to dosing of atorvastatin, a significant decrease in serum cortisol was observed with levoketoconazole vs. placebo (p < 0.005) and vs. ketoconazole (p < 0.05) on day 4	AEs (>10% of participants): levoketoconazole + atorvastatin vs. ketoconazole + atorvastatin vs. placebo + atorvastatin: headache: 25.0% vs. 21.7% vs. 17.4%; back pain: 12.5% vs. 8.7% vs 0%; nausea: 12.5%, 13.0% vs. 0%
Metformin DDI study (COR-2017-03)	N/A	Open-label, fixed-sequence, 3-period study	Healthy volunteers (N = 32)	Period 1: metformin 500 mg single dose on day1 (fed) Period 2: levoketoconazole bid dosing by weekly titration from 300 mg/d to 900 or 1200 mg/d Period 3: levoketoconazole 450 mg bid plus metformin 500 mg single dose (fed)	Both Cmax and AUC of metformin were increased ~2-fold following steady-state dosing of levoketoconazole (GSLM ratio of metformin administered with vs. without levoketoconazole: AUC0-last, 2.2 [90% CI: 2.0, 2.4]; Cmax, 1.8 [90% CI: 1.7, 2.0]; clearance, 0.4 [90% CI: 0.3, 0.5])	11 participants discontinued from study due to AEs (abnormal hepatic function [n = 6]; headache [n = 2], decreased cortisol [n = 1], increased blood creatinine [n = 1], vomiting [n = 1])
DM2 study (DIO-501)	N/A	Randomized, double-blind, placebo-controlled, parallel-group study	Patients with DM2 (N = 35) Age range: 18–70 y	Levoketoconazole (200 [n = 10], 400 [n = 6], and 600 [n = 4] mg qd); ketoconazole 400 mg qd (n = 8), or placebo (n = 6) for 14 d day 1 (single dose) and day 14 (steady state)	Administration of 200 mg levoketoconazole resulted in similar levoketoconazole AUC as 400 mg of ketoconazole at day 1 (AUC0-last: 23.9 vs. 26.2 μg/mL*h) and day 14 (39.4 vs. 38.5 μg/mL*h) After dosing with ketoconazole, Cmax and AUC of levoketoconazole were consistently higher (~3-fold) than those of the 2R,4S enantiomer	AEs (≥3 patients overall): headache (levoketoconazole vs. ketoconazole vs. placebo: 20.0–50.0% vs. 12.5% vs. 0%), nausea (30.0–50.0% vs. 0% vs. 16.7%), and diarrhea (10.0–33.3% vs. 0% vs. 0%)

*Mild elevated AST (n = 1) and moderate elevated AST, ALT, bilirubin T (n = 1); both AEs resolved.

AE: adverse event; ALT: alanine aminotransferase; AST: aspartate aminotransferase; AUC: area under the curve; AUC_0-inf: AUC from time 0 extrapolated to infinity; AUC_0-last: AUC from time 0 to the last time with a measurable value; bid: twice daily; CI: confidence interval; C_max: maximum plasma concentration; DDI: drug-drug interaction; DM2: diabetes mellitus type 2; GSLM: geometric least squares mean; LSM: least squares mean; N/A = not applicable; PK: pharmacokinetics; qd: once daily; t_1/2: terminal half-life; T_max: time to maximum plasma concentration.

Figure 3. Mean urinary free cortisol (mUFC) concentration from baseline of the dose titration phase through the end of the maintenance phase in SONICS (maintenance population)

Reprinted with permission from Lancet Diabetes Endocrinol, vol. 7/no. 11, Fleseriu M, et al., Efficacy and safety of levoketoconazole in the treatment of endogenous Cushing’s syndrome (SONICS): a phase 3, multicentre, open-label, single-arm trial, pg, 855–865 [50], Copyright 2019, with permission from Elsevier.

Figure 4. Mean free testosterone levels in males (A) and females (B) and hirsutism scores in females (C), from baseline through the end of the maintenance phase in SONICS (maintenance population). *p < 0.0001. ^†p < 0.001. SEM: standard error of the mean

Reprinted from Geer EB, et al. Pituitary; published online ahead of print 20 November 2020 [60], via a Creative Commons Attribution 4.0 International License.

Figure 5. Measures of glycemic control over time: HbA1c (A) and fasting blood glucose (B) in SONICS (maintenance population). D: day; DM: diabetes mellitus; FBG: fasting blood glucose; HbA1c: hemoglobin A1c; M: month; SE: standard error

Reprinted from Pivonello R, et al. Frontiers Endocrinol. 2021;12:59894 [71], via a Creative Commons Attribution (CC BY) license.

Table 3. Safety profiles of levoketoconazole and ketoconazole

	Levoketoconazole	Ketoconazole
Adverse events of interest
Liver function	SONICS study (N = 94) [57]: Liver-related AEs: 7.4% ALT >5X ULN: 3.2% AST >3X ULN: 4.3% GGT >5X ULN: 2.1% ALP >3X ULN: 0% Total bilirubin >2X ULN: 0%	Ketoconazole use as an antifungal therapy Incidence of asymptomatic increases in liver enzymes: ~12% (range of 0–48%) [73,74] Incidence of symptomatic, potentially serious hepatic injury: 1 in 15,000 pts (rare) [73,74] EMA withdrew marketing authorization for use as an antifungal agent because of hepatotoxic risk [28]; remains approved for CS US FDA requires a boxed warning for hepatotoxicity in the label for fungal infection indication [25] Ketoconazole use for treatment of CS French compassionate use program (47 ketoconazole treatment-naïve pts treated for 6 months*) [72]: Liver injury^†: 8.5% ALT ≥5X ULN: 12.9% AST ≥3X ULN: 3.2% GGT ≥5X ULN: 16.7% ALP ≥3X ULN: 3.4% Total bilirubin ≥3X ULN: 5.0% Increase in liver enzymes in a large retrospective study (N = 200): 16% of treated pts [51]
QT interval prolongation	SONICS study (N = 94) [57] Incidence of QT prolongation AE: 5.3%	US FDA requires a boxed warning in the label for antifungal use about QT prolongation and drug interactions leading to QT prolongation [25] Ketoconazole is known to prolong QT interval and increase risk of TdP by Direct effect through KCNH2 IKr channel [28,75] Drug-drug interaction with QT-prolonging drugs [28,29] Retrospective analysis (pts with CD; N = 15): ketoconazole treatment was not associated with abnormal QTc [67]
Adrenal insufficiency	SONICS study (N = 94) [57] Incidence of adrenal insufficiency AE: 3.2%	Incidence of adrenal insufficiency AE in CS studies: 0–18.5% [51,52,62,72,76]
Other safety parameters
Testosterone	SONICS study (N = 94) [57] Significant decrease in mean free testosterone levels in women from baseline to EoM (0.3 to 0.1 ng/dL; p < 0.0001)^‡ Mean free testosterone levels increased numerically in men from baseline to EoM (5.1 to 5.8 ng/dL)^‡ Significant improvements in hirsutism (in females) and acne from baseline to EoM (p < 0.01)	Ketoconazole, when used as an antifungal drug, can reduce gonadal testosterone synthesis, resulting in hypogonadism and gynecomastia in men [63,65] Retrospective analysis (pts with CS with elevated serum androgen levels; N = 12): ketoconazole inhibited adrenal androgen synthesis in both men (n = 3) and women (n = 9) [61] Retrospective analysis (pts with CD; N = 8): plasma testosterone levels did not change with ketoconazole treatment [66]

*Most relevant comparison with SONICS study.

^†Liver injury was considered if 1 of the 4 following conditions was met: (1) ALT > 3X ULN, (2) AST > 3X ULN if ALT ≤ 3X ULN, (3) total bilirubin > 2X ULN or (4) both ALP > 2X ULN and ALT > ULN.

^‡Free testosterone reference levels: men age 18–69, 4.6–22.4 ng/dL; men age 70–89, 0.6–7.3 ng/dL; women age 18–69, 0.02–0.5 ng/dL; women age 70–89, 0.03–0.5 ng/dL.

AE: adverse event; ALP: alkaline phosphatase; ALT: alanine aminotransferase; AST: aspartate aminotransferase; CD: Cushing’s disease; CS: Cushing’s syndrome; EMA: European Medicines Agency; EoM: end of maintenance; GGT: gamma glutamyl transferase; pt: patient; TdP: torsades de pointes; ULN: upper limit of normal; US FDA: United States Food and Drug Administration.

Rotstein DM, Kertesz DJ, Walker KA, et al. Stereoisomers of ketoconazole: preparation and biological activity. J Med Chem. 1992 Jul 24;35(15):2818–2825.

 PubMed Web of Science ®Google Scholar

Auchus RJ, Wu Y, Liu J, et al. 2S,4R-ketoconazole is the relevant enantiomer of ketoconazole for cortisol synthesis inhibition: steroidogenic P450s inhibition involves multiple mechanisms [abstract]. Endocr Rev. 2018;39(2 suppl). https://www.endocrine.org/meetings-and-events/endo-annual-meetings?ID=46236 

 Google Scholar

Thieroff-Ekerdt RI, Mould DR Differential pharmacokinetics of levoketoconazole (COR-003), the single 2S,4R-enantiomer of ketoconazole, a new investigational drug for the treatment of Cushing's syndrome. 18th European Congress of Endocrinology (ECE); 2016 May 28–31; Munich, Germany.

 Google Scholar

Thieroff-Ekerdt R, Lavin P, Abou-Gharbia M, et al. Pharmacology of COR-003 (levoketoconazole), an investigational treatment for endogenous Cushing's syndrome. 98th Annual Meeting and Expo of the Endocrine Society (ENDO); 2016 Apr 1–4; Boston, MA.

 Google Scholar

Boudriau S, Demnati R, Swearingen D, et al. Differential effects of co-administration of racemic ketoconazole and levdexketoconazole of the pharmacokinetic profile of atorvastatin. American Society of Clinical Pharmacology and Therapeutics (ASCPT); 2008 Apr 2–5; Orlando, FL.

 Google Scholar

Fleseriu M, Pivonello R, Elenkova A, et al., Efficacy and safety of levoketoconazole in the treatment of endogenous Cushing's syndrome (SONICS): a phase 3, multicentre, open-label, single-arm trial. Lancet Diabetes Endocrinol. 2019;7(211): 855–865.

 PubMedGoogle Scholar

Geer EB, Salvatori R, Elenkova A, et al., Levoketoconazole improves clinical signs and symptoms and patient-reported outcomes in patients with Cushing's syndrome. Pituitary. 2021;24(1): 104–115.

 PubMed Web of Science ®Google Scholar

Pivonello R, Elenkova A, Fleseriu M, et al. Levoketoconazole in the treatment of patients with Cushing's syndrome and diabetes mellitus: phase 3 SONICS results. Front Endocrinol. 2021;12:595894.

 PubMed Web of Science ®Google Scholar

Fleseriu M, Pivonello R, Elenkova A, et al. Levoketoconazole in the treatment of endogenous Cushing's syndrome: secondary endpoint results from a phase 3 study (SONICS). 16th International Pituitary Congress; 2019 Mar 20–22; New Orleans, LA.

 Google Scholar

Lewis JH, Zimmerman HJ, Benson GD, et al. Hepatic injury associated with ketoconazole therapy. Analysis of 33 cases. Gastroenterology. 1984;86(3):503–513.

 PubMed Web of Science ®Google Scholar

Lake-Bakaar G, Scheuer PJ, Sherlock S, et al. Hepatic reactions associated with ketoconazole in the United Kingdom. Br Med J (Clin Res Ed). 1987;294(11):419–422.

 PubMedGoogle Scholar

European Medicines Agency Committee for Medicinal Products for Human Use. Ketoconazole HRA: assessment report. London. 2014.

 Google Scholar

Ketoconazole tablets USP, 200 mg. Haifa Bay, Israel: Taro Pharmaceutical Industries Ltd.; 2017.

 Google Scholar

Young J, Bertherat J, Vantyghem MC, et al. Hepatic safety of ketoconazole in Cushing's syndrome: results of a compassionate use programme in France. Eur J Endocrinol. 2018 May;178(5):447–458.

 PubMed Web of Science ®Google Scholar

Castinetti F, Guignat L, Giraud P, et al. Ketoconazole in Cushing's disease: is it worth a try?. J Clin Endocrinol Metab. 2014 May;99(5):1623–1630.

 PubMed Web of Science ®Google Scholar

Takemasa H, Nagatomo T, Abe H, et al. Coexistence of hERG current block and disruption of protein trafficking in ketoconazole-induced long QT syndrome. Br J Pharmacol. 2008 Feb;153(3)439–447.

 PubMed Web of Science ®Google Scholar

Boyce MJ, Baisley KJ, Warrington SJ, et al. Pharmacokinetic interaction between domperidone and ketoconazole leads to QT prolongation in healthy volunteers: a randomized, placebo-controlled, double-blind, crossover study. Br J Clin Pharmacol. 2012 Mar;73(3)411–421.

 PubMed Web of Science ®Google Scholar

De Martin M, Toja PM, Goulene K, et al. No untoward effect of long-term ketoconazole administration on electrocardiographic QT interval in patients with Cushing's disease. Basic Clin Pharmacol Toxicol. 2016 Apr;118(4)279–283.

 PubMed Web of Science ®Google Scholar

Castinetti F, Morange I, Jaquet P, et al. Ketoconazole revisited: a preoperative or postoperative treatment in Cushing's disease. Eur J Endocrinol. 2008 Jan;158(1)91–99.

 PubMed Web of Science ®Google Scholar

Sonino N, Boscaro M, Paoletta A, et al. Ketoconazole treatment in Cushing's syndrome: experience in 34 patients. Clin Endocrinol (Oxf). 1991 Oct;35(4)347–352.

 PubMed Web of Science ®Google Scholar

Moncet D, Morando DJ, Pitoia F, et al. Ketoconazole therapy: an efficacious alternative to achieve eucortisolism in patients with Cushing's syndrome. Medicina (B Aires). 2007;67(1):26–31.

 PubMed Web of Science ®Google Scholar

Pont A, Williams PL, Azhar S, et al. Ketoconazole blocks testosterone synthesis. Arch Intern Med. 1982;142(12):2137–2140.

 PubMed Web of Science ®Google Scholar

DeFelice R, Johnson DG, Galgiani JN, et al. Gynecomastia with ketoconazole. Antimicrob Agents Chemother. 1981;19(6):1073–1074.

 PubMed Web of Science ®Google Scholar

Weber MM, Luppa P, Engelhardt D, et al. Inhibition of human adrenal androgen secretion by ketoconazole. Klin Wochenschr. 1989;67(14):707–712.

 PubMedGoogle Scholar

Mortimer RH, Cannell GR, Thew CM, et al. Ketoconazole and plasma and urine steroid levels in Cushing's disease. Clin Exp Pharmacol Physiol. 1991;18(8):563–569.

 PubMed Web of Science ®Google Scholar