Details of the Drug Combination

General Information of Drug Combination (ID: DCDFSM5)

• Drug Combination Name: Letrozole + Anastrozole
• Indication: Anatomic Stage I Breast Cancer AJCC v8; Status: Phase 2 [1]
• Component Drugs:
  Letrozole (DMH07Y3): Small molecular drug
  Anastrozole (DMNP60F): Small molecular drug

Molecular Interaction Atlas of This Drug Combination

Indication(s) of Letrozole

Disease Entry	ICD 11	Status	REF
Estrogen-receptor positive breast cancer	N.A.	Approved	[2]
Hormonally-responsive breast cancer	2C60-2C65	Approved	[3]

Letrozole Interacts with 1 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	TTSZLWK	CP19A_HUMAN	Inhibitor	[6]

Letrozole Interacts with 3 DME Molecule(s)

DME Name	DME ID	UniProt ID	Mode of Action	REF
Cytochrome P450 3A4 (CYP3A4)	DE4LYSA	CP3A4_HUMAN	Metabolism	[7]
Aromatase (CYP19A1)	DEQX145	CP19A_HUMAN	Metabolism	[8]
Cytochrome P450 2A6 (CYP2A6)	DEJVYAZ	CP2A6_HUMAN	Metabolism	[9]

Letrozole Interacts with 18 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	OTZ6XF74	CP19A_HUMAN	Decreases Activity	[10]
Cytochrome P450 3A4 (CYP3A4)	OTQGYY83	CP3A4_HUMAN	Increases Oxidation	[11]
Cytochrome P450 2A6 (CYP2A6)	OT52TWG3	CP2A6_HUMAN	Increases Oxidation	[11]
Adenylate kinase isoenzyme 1 (AK1)	OT614AR3	KAD1_HUMAN	Increases ADR	[12]
Dickkopf-related protein 1 (DKK1)	OTRDLUSP	DKK1_HUMAN	Increases Expression	[13]
Follitropin subunit beta (FSHB)	OTGLS283	FSHB_HUMAN	Increases Expression	[14]
Lutropin subunit beta (LHB)	OT5GBOVJ	LSHB_HUMAN	Increases Expression	[14]
Progesterone receptor (PGR)	OT0FZ3QE	PRGR_HUMAN	Decreases Expression	[15]
Leukemia inhibitory factor (LIF)	OTO46S5S	LIF_HUMAN	Increases Expression	[13]
Gap junction alpha-1 protein (GJA1)	OTT94MKL	CXA1_HUMAN	Decreases Expression	[16]
G1/S-specific cyclin-D1 (CCND1)	OT8HPTKJ	CCND1_HUMAN	Decreases Expression	[17]
G1/S-specific cyclin-D2 (CCND2)	OTDULQF9	CCND2_HUMAN	Decreases Expression	[17]
Cyclin-dependent kinase inhibitor 1 (CDKN1A)	OTQWHCZE	CDN1A_HUMAN	Increases Expression	[18]
Leukemia inhibitory factor receptor (LIFR)	OT36W9O5	LIFR_HUMAN	Increases Expression	[13]
Proliferation marker protein Ki-67 (MKI67)	OTA8N1QI	KI67_HUMAN	Decreases Expression	[15]
Small ribosomal subunit protein eS6 (RPS6)	OTT4D1LN	RS6_HUMAN	Decreases Phosphorylation	[17]
Lanosterol 14-alpha demethylase (CYP51A1)	OTAYHG9C	CP51A_HUMAN	Decreases Activity	[19]
Fibroblast growth factor 22 (FGF22)	OTVIX6J0	FGF22_HUMAN	Increases Expression	[13]

Indication(s) of Anastrozole

Disease Entry	ICD 11	Status	REF
Breast cancer	2C60-2C65	Approved	[4]
Estrogen-receptor positive breast cancer	N.A.	Approved	[5]
Obesity	5B81	Approved	[5]

Anastrozole Interacts with 1 DTT Molecule(s)

DTT Name	DTT ID	UniProt ID	Mode of Action	REF
Aromatase (CYP19A1)	TTSZLWK	CP19A_HUMAN	Inhibitor	[20]

Anastrozole Interacts with 1 DTP Molecule(s)

DTP Name	DTP ID	UniProt ID	Mode of Action	REF
Putative sodium-coupled neutral amino acid transporter 7 (SLC38A7)	DT2EGUN	S38A7_HUMAN	Substrate	[21]

Anastrozole Interacts with 6 DME Molecule(s)

DME Name	DME ID	UniProt ID	Mode of Action	REF
Cytochrome P450 3A4 (CYP3A4)	DE4LYSA	CP3A4_HUMAN	Metabolism	[22]
UDP-glucuronosyltransferase 1A1 (UGT1A1)	DEYGVN4	UD11_HUMAN	Metabolism	[22]
Cytochrome P450 3A5 (CYP3A5)	DEIBDNY	CP3A5_HUMAN	Metabolism	[22]
Cytochrome P450 2C8 (CYP2C8)	DES5XRU	CP2C8_HUMAN	Metabolism	[22]
UDP-glucuronosyltransferase 2B7 (UGT2B7)	DEB3CV1	UD2B7_HUMAN	Metabolism	[22]
UDP-glucuronosyltransferase 1A3 (UGT1A3)	DEF2WXN	UD13_HUMAN	Metabolism	[22]

Anastrozole Interacts with 6 DOT Molecule(s)

DOT Name	DOT ID	UniProt ID	Mode of Action	REF
Adenylate kinase isoenzyme 1 (AK1)	OT614AR3	KAD1_HUMAN	Increases ADR	[12]
Progesterone receptor (PGR)	OT0FZ3QE	PRGR_HUMAN	Decreases Expression	[15]
Aromatase (CYP19A1)	OTZ6XF74	CP19A_HUMAN	Decreases Activity	[10]
NADPH--cytochrome P450 reductase (POR)	OTVIDOCH	NCPR_HUMAN	Decreases Activity	[23]
Gap junction alpha-1 protein (GJA1)	OTT94MKL	CXA1_HUMAN	Decreases Expression	[16]
Proliferation marker protein Ki-67 (MKI67)	OTA8N1QI	KI67_HUMAN	Decreases Expression	[24]

Test Results of This Drug Combination in Other Disease Systems

Indication	DrugCom ID	Cell Line	Status	REF
Breast Cancer	DCU90CT	N. A.	Phase 3	[25]
Breast Cancer	DCF5OEQ	N. A.	Phase 2	[26]
Breast Cancer	DC9ZJJD	N. A.	Phase 1	[27]

References

• [1] ClinicalTrials.gov (NCT04294225) Anastrozole and Letrozole After Surgery for the Treatment of Stage I-III Breast Cancer
• [2] Letrozole FDA Label
• [3] URL: http://www.guidetopharmacology.org Nucleic Acids Res. 2015 Oct 12. pii: gkv1037. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands. (Ligand id: 5209).
• [4] URL: http://www.guidetopharmacology.org Nucleic Acids Res. 2015 Oct 12. pii: gkv1037. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands. (Ligand id: 5137).
• [5] Anastrozole FDA Label
• [6] Aromatase inhibitors--theoretical concept and present experiences in the treatment of endometriosis. Zentralbl Gynakol. 2003 Jul-Aug;125(7-8):247-51.
• [7] Inhibition of drug metabolizing cytochrome P450s by the aromatase inhibitor drug letrozole and its major oxidative metabolite 4,4'-methanol-bisbenzonitrile in vitro. Cancer Chemother Pharmacol. 2009 Oct;64(5):867-75.
• [8] Double-blind, randomised, multicentre endocrine trial comparing two letrozole doses, in postmenopausal breast cancer patients. Eur J Cancer. 1999 Feb;35(2):208-13.
• [9] Letrozole concentration is associated with CYP2A6 variation but not with arthralgia in patients with breast cancer. Breast Cancer Res Treat. 2018 Nov;172(2):371-379.
• [10] Aromatase inhibition: translation into a successful therapeutic approach. Clin Cancer Res. 2005 Apr 15;11(8):2809-21. doi: 10.1158/1078-0432.CCR-04-2187.
• [11] Deactivation of anti-cancer drug letrozole to a carbinol metabolite by polymorphic cytochrome P450 2A6 in human liver microsomes. Xenobiotica. 2009 Nov;39(11):795-802. doi: 10.3109/00498250903171395.
• [12] ADReCS-Target: target profiles for aiding drug safety research and application. Nucleic Acids Res. 2018 Jan 4;46(D1):D911-D917. doi: 10.1093/nar/gkx899.
• [13] Clomiphene citrate versus letrozole: molecular analysis of the endometrium in women with polycystic ovary syndrome. Fertil Steril. 2011 Oct;96(4):1051-6. doi: 10.1016/j.fertnstert.2011.07.1092.
• [14] Aromatase inhibition, testosterone, and seizures. Epilepsy Behav. 2004 Apr;5(2):260-3. doi: 10.1016/j.yebeh.2003.12.001.
• [15] Aromatase inhibitors: cellular and molecular effects. J Steroid Biochem Mol Biol. 2005 May;95(1-5):83-9. doi: 10.1016/j.jsbmb.2005.04.010.
• [16] Inhibition of estrogen receptor reduces connexin 43 expression in breast cancers. Toxicol Appl Pharmacol. 2018 Jan 1;338:182-190. doi: 10.1016/j.taap.2017.11.020. Epub 2017 Nov 24.
• [17] Dual inhibition of mTOR and estrogen receptor signaling in vitro induces cell death in models of breast cancer. Clin Cancer Res. 2005 Jul 15;11(14):5319-28. doi: 10.1158/1078-0432.CCR-04-2402.
• [18] Synergistic activity of letrozole and sorafenib on breast cancer cells. Breast Cancer Res Treat. 2010 Nov;124(1):79-88. doi: 10.1007/s10549-009-0714-5. Epub 2010 Jan 7.
• [19] Comparison of lanosterol-14 alpha-demethylase (CYP51) of human and Candida albicans for inhibition by different antifungal azoles. Toxicology. 2006 Nov 10;228(1):24-32. doi: 10.1016/j.tox.2006.08.007. Epub 2006 Aug 12.
• [20] Effective aromatase inhibition by anastrozole in a patient with gonadotropin-independent precocious puberty in McCune-Albright syndrome. J Pediatr Endocrinol Metab. 2002;15 Suppl 3:945-8.
• [21] Anastrozole Aromatase Inhibitor Plasma Drug Concentration Genome-Wide Association Study: Functional Epistatic Interaction Between SLC38A7 and ALPPL2. Clin Pharmacol Ther. 2019 Jan 16.
• [22] In vitro and in vivo oxidative metabolism and glucuronidation of anastrozole. Br J Clin Pharmacol. 2010 Dec;70(6):854-69.
• [23] Assessment of Five Pesticides as Endocrine-Disrupting Chemicals: Effects on Estrogen Receptors and Aromatase. Int J Environ Res Public Health. 2022 Feb 10;19(4):1959. doi: 10.3390/ijerph19041959.
• [24] Biomarker changes during neoadjuvant anastrozole, tamoxifen, or the combination: influence of hormonal status and HER-2 in breast cancer--a study from the IMPACT trialists. J Clin Oncol. 2005 Apr 10;23(11):2477-92. doi: 10.1200/JCO.2005.07.559. Epub 2005 Mar 14.
• [25] ClinicalTrials.gov (NCT02730091) A Open Study of Metronomic Oral Vinorelbine in Combination With Aromatase Inhibitors for the Treatment of Postmenopausal Women With Hormone Receptor Positive,HER2-negative, Advanced Breast Cancer Who Received no Prior Therapy for Advanced Disease
• [26] ClinicalTrials.gov (NCT02585388) Addition of Aromatase at the Navelbine in Pretreated Metastatic Breast Cancer.
• [27] ClinicalTrials.gov (NCT00681928) Cognitive Function in Older Women With Stage I, Stage II, or Stage III Breast Cancer Receiving Hormone Therapy