Zilurgisertib

CAS 2173389-57-4

MW 502.6 g/mol MFC₃₀H₃₈N₄O₃

Atebrioz, FDA 2026, APPROVALS 2026, L5Z9S25HO2, INCB 000928

2-amino-N-(4-hydroxy-1-bicyclo[2.2.2]octanyl)-5-[4-[(1R,5S)-3-(oxan-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl]phenyl]pyridine-3-carboxamide

To reduce the volume of total new heterotopic ossification in adults and pediatric patients 12 years and older with fibrodysplasia ossificans progressiva

Zilurgisertib is an inhibitor of activin A receptor type 1 (activin receptor-like kinase 2; ALK2; ALK-2; ACVR1; ACTR-I), with potential anti-anemic and ossification suppressive activities. Upon administration, zilurgisertib targets, binds to and inhibits the activity of ALK-2. This prevents ALK2-mediated signaling and ALK2-mediated excessive bone morphogenetic protein (BMP) signaling. This may suppress heterotopic ossification (HO). As ALK-2 enhances the secretion of hepcidin, a peptide liver hormone and a key modulator of iron homeostasis, zilurgisertib is able to decrease hepcidin expression in the liver, thereby increasing and restoring plasma iron levels, enhancing erythropoiesis, and correcting anemia of chronic disease (ACD). ALK2, a serine/threonine receptor kinase and type I cell surface receptor for BMPs, is constitutively activated due to activating mutations in inflammatory conditions, various types of cancer, and in fibrodysplasia ossificans progressiva (FOP). Elevated serum hepcidin levels enhance storage of iron, reduce iron availability and causes iron deficiency anemia.

Zilurgisertib, sold under the brand name Atebrioz, is a medication used for the treatment of fibrodysplasia ossificans progressiva.^[1] It is an selective activin receptor-like kinase-2 (ALK2) inhibitor.^[1][2]

Zilurgisertib was approved for medical use in the United States in September of 2026.^[3]

Medical uses

Zilurgisertib is indicated to reduce the volume of total new heterotopic ossification (abrnomal bone formation) in people aged twelve years of age and older with fibrodysplasia ossificans progressiva.^[1]

Fibrodysplasia ossificans progressiva is a rare genetic disease caused certain mutations in the ACVR1/ALK2 gene which controls new bone growth.^[3] As a result, connective tissues such as muscle, tendons, and ligaments gradually turn into bone, causing limited movement, deformities, severe disability, and early death.^[3]

Adverse effects

Zilurgisertib can cause fetal harm based on data from animal studies.^[3]

The most common side effects include headache, joint pain, upper respiratory tract infection, nosebleeds, and nausea.^[3]

History

The effectiveness of zilurgisertib was evaluated in a randomized, double-blind, placebo‑controlled trial (NCT05090891) in which 63 participants with FOP were randomly assigned to receive zilurgisertib 100 mg or placebo once daily for 24 weeks followed by a 292-week, single-arm, open-label extension period during which participants received oral zilurgisertib 100 mg daily.^[3]

Society and culture

Legal status

Zilurgisertib was approved for medical use in the United States in September 2026.^[4] The US Food and Drug Administration granted the application for zilurgisertib fast track, priority review, and orphan drug designations for this indication.^[3]

Names

Zilurgisertib is the international nonproprietary name.^[5]

Zilurgisertib is sold under the brand name Atebrioz.^[3]

PAT

https://patentscope.wipo.int/search/en/detail.jsf?docId=US242623881&_cid=P22-MUNHEN-48106-1

Example 34: 2-amino-N-(4-hydroxybicyclo[2.2.2]octan-1-yl)-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinamide (also named compound A herein)

To a solution of 2-amino-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinic acid TFA salt (Intermediate 14a, 4.10 g, 8.14 mmol) and 4-aminobicyclo[2.2.2]octan-1-ol hydrochloride (2.17 g, 12.2 mmol) in anhydrous DMF (60 mL) was added N-methylmorpholine (2.24 mL, 20.4 mmol) and HATU (4.64 g, 12.2 mmol) under a nitrogen atmosphere at RT. The reaction mixture was stirred for 2 h and then diluted with a sat. aq. solution of NaHCO 3 and extracted three times with EtOAc. The combined organic extracts were washed with brine, dried over MgSO 4, filtered and concentrated under reduced pressure. The crude product was purified by reversed-phase chromatography (Method 3b). Pure fractions were treated with a sat. aq. NaHCO 3 solution and extracted three times with EtOAc. The combined organic extracts were washed with brine, dried over MgSO 4, filtered and concentrated under reduced pressure to give the title compound as an off-white solid. The absolute configuration as depicted was confirmed by X-ray crystallography of the title compound in a complex with the ALK-2 kinase domain. 1H NMR (400 MHz, DMSO-d6) δ 8.34 (d, 1H), 7.98 (d, 1H), 7.79 (s, 1H), 7.57 (d, 2H), 7.23 (d, 2H), 6.92 (s, 2H), 4.31 (s, 1H), 3.91-3.78 (m, 2H), 3.40 (bs, 1H), 3.33-3.24 (m, 2H), 3.11 (d, 1H), 2.57 (bs, 1H), 2.50-2.34 (m, 1H), 2.34 (bs, 1H), 2.12-1.94 (m, 6H), 1.90-1.72 (m, 3H), 1.71-1.51 (m, 6H), 1.51-1.34 (m, 2H), 1.31 (t, 1H), 0.82-0.68 (m, 1H). (UPLC-MS) t R 0.54 min; ESI-MS 503 [M+H] +. Chiral HPLC (ChiralPak Id, 5 μm, flow rate: 1 mL/min, detection wavelength: 270 nm, mobile phase: heptane:isopropanol 60:40 (+0.1% diethylamine)): t R 18.7 min, 92.3% ee.

Alternative Example 34A: To a solution of 2-amino-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinic acid hydrochloride (1 kg, 1.683 mol) and 4-aminobicyclo[2.2.2]octan-1-ol hydrochloride (343.9 g, 1.935 mol) in DMF (3500 mL) was added Et 3N (681.2 g, 6.732 mol) and HATU (767.9 g, 2.019 mol) at RT. The reaction mixture was stirred at RT for 1 h. The mixture was heated to IT=45° C., 5% NH 3.H 2O solution (5200 g) was added. Stirred for about 30 min, another 5% NH 3.H 2O solution (1800 g) was added. The mixture was heated to IT=45° C. for 2 h. The mixture was cooled to IT=22° C. Filtered, the wet cake was washed with H 2O (1500 mL×3). The wet cake was dried under vacuum at 45° C. for 24 h. The crude product was dissolved in acetone (3000 mL), then filtered to remove some undissolved solid. The filtrate was heated to IT=50° C. H 2O (2000 mL) was added. The mixture was stirred at IT=50° C. for 30 min until a white precipitate formed. H 2O (4000 mL) was added slowly. The mixture was stirred at IT=50° C. for 2 h. The mixture was cooled to IT=22° C. in 2 h, Filtered, the wet cake was washed with acetone:H 2O=1:2 (v/v, 1000 mL×2). The wet cake was dried under vacuum at 45° C. for 24 h. total 760 g white solid was obtained (89% yield, 99.4% ee).

1H NMR (DMSO-d6) δ: 8.32 (d, J=2.3 Hz, 1H), 7.97 (d, J=2.3 Hz, 1H), 7.77 (s, 1H), 7.54 (d, J=8.3 Hz, 2H), 7.20 (d, J=8.4 Hz, 2H), 6.90 (s, 2H), 4.31 (s, 1H), 3.82 (m, 2H), 3.29 (m, 2H), 3.07 (d, J=8.5 Hz, 1H), 2.54 (d, J=8.3 Hz, 1H), 2.44 (dd, J=8.5, 3.5 Hz, 1H), 2.37 (m, 1H), 2.31 (td, J=10.2, 5.0 Hz, 1H), 2.04 (m, 6H), 1.80 (dt, J=7.9, 3.8 Hz, 1H), 1.71 (d, J=12.3 Hz, 1H), 1.65 (d, J=11.5 Hz, 1H), 1.62 (m, 6H), 1.38 (m, 1H), 1.34 (m, 1H), 1.29 (t, J=3.9 Hz, 1H), 0.73 (dd, J=7.9, 3.6 Hz, 1H).

13C NMR (DMSO-d6) δ: 167.80, 157.69, 148.28, 141.27, 134.91, 134.79, 126.40, 125.66, 123.53, 111.01, 66.22, 65.59, 59.10, 55.46, 52.04, 33.72, 31.92, 31.77, 30.59, 29.61, 24.14, 17.20.

MS(ESI-TOF): 503.3018 [M+H]+.

The starting material (hydrochloride salt) was obtained as follows:

Methyl 2-amino-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinate dihydrochloride (10 g, 19.5 mmol, 1.0 eq) was suspended in MeOH (31.7 g). A solution of NaOH (2.9 g, 72.2 mmol, 3.7 eq) in H 2O (10 g) was then added. The reaction mixture was heated to 45±5° C. and stirred for more than 3 h, yielding a suspension.

To another flask containing acetone (200 g), 5˜6 N HCl in i-PrOH (14.8 g, 97.6 mmol, 5 eq) was added. The solution was heated to 47±3° C. Then the above MeOH suspension was added to the mixture dropwise and stirred at 47±3° C. for 3 h. The mixture was cooled down to 23±3° C. and stirred for 3 h. After filtration, the wet cake was washed with acetone (40 g). The wet cake was dried under vacuum at 55° C. for 8 h. 2-Amino-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinic acid hydrochloride (12.3 g, 99.3% HPLC purity, 62.1% assay yield) was obtained as an off-white solid.

1H NMR (DMSO-d6) δ: 11.53 (br s, 1H), 8.64 (br s, 1H), 8.54 (br s, 1H), 7.72-8.42 (m, 2H), 7.64 (br d, J=7.9 Hz, 2H), 7.38 (br d, J=7.8 Hz, 2H), 3.85-4.04 (m, 3H), 3.40-3.73 (m, 4H), 3.15-3.33 (m, 2H), 2.18 (br d, J=3.9 Hz, 1H), 1.95-2.12 (m, 4H), 1.88 (br d, J=10.0 Hz, 1H), 1.05 (br t, J=6.4 Hz, 1H).

13C NMR (DMSO-d6) δ: 167.2, 155.8, 144.3, 142.0, 139.6, 133.8, 127.7, 126.3, 124.1, 110.0, 65.8, 62.5, 55.7, 53.2, 29.9, 28.8, 28.7, 23.5, 16.6.

MS(ESI-TOF): 380.1974 [M+H] +.

The starting material, 2-Amino-5-(4-((1R,5S)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-1-yl)phenyl)nicotinate dihydrochloride, was obtained as follows:

To a 500 mL round bottom flask were charged 1R,5S)-1-(4-bromophenyl)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-3-ium chloride (20 g, 1 eq), EA (200 mL), and 25% K 2CO 3 (62 g). The mixture was stirred for 30 min until all solids were dissolved. After phase separation, the organic layer was concentrated. 2-Methyl-2-butanol (48 g, 60 mL) was added. The organic layer was concentrated. 2-Methyl-2-butanol (144 g, 180 mL) was added.

The mixture was transferred to a 500 mL Redlay. K 2CO 3 (18.8 g, 2.5 eq) and methyl 2-amino-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)nicotinate (16.8 g, 1.04 eq; see Intermediate 1e) were added. The mixture was degassed with N 2 for three times. The mixture was heated to IT=50±5° C. within 1 h. Pd(dppf)Cl 2 (1.2 g, 0.03 eq) was added. The mixture was heated to IT=70±3° C. and stirred for 2 h. After cooling to 22° C., H 2O (120 g) and EA (180 g) were added and stirred for 30 min. MCC (6 g) was added and the mixture was filtered through MCC. The cake was washed with EA (54 g). After phase separation, the organic layer was washed with 5% NaCl (124 g). Quadrasil MP (Heavy metal scavenger from Johnson Matthey, 6 g) was then added to the organic layer. The mixture was heated to IT=55° C. for 8 h, filtered through MCC and washed with EA (54 g). Quadrasil MP (2 g) was added to the organic layer. The mixture was heated to IT=55° C. for 6 h, filtered through CMC and washed with EA (54 g). The organic layer was concentrated. Acetone (158 g, 200 mL) was added. After stirring at IT=22±3° C. for 30 min, the mixture was heated to IT=40±3° C. 15.5% HCl (38.4 g) was added dropwise with IT<50° C. The mixture was stirred at IT=45±3° C. for 1 h. The mixture was cooled to 22±3° C. The mixture was stirred at 22±3° C. for 1 h and filtered. The cake was washed with acetone (32 g×2). The wet cake was dried under vacuum at 50° C. for at least 8 h. The starting material was obtained, 22.5 g white solid (97.1% HPLC purity, 5.2% water content, 87% assay yield) was obtained.

1H NMR (DMSO-d6) δ: 11.43 (br d, J=5.7 Hz, 1H), 8.62-8.80 (m, 2H), 7.85-8.58 (m, 2H), 7.67 (d, J=8.3 Hz, 2H), 7.39 (d, J=8.4 Hz, 2H), 3.85-4.06 (m, 6H), 3.60-3.69 (m, 2H), 3.50-3.59 (m, 1H), 3.44 (brd, J=7.7 Hz, 1H), 3.14-3.31 (m, 2H), 2.21 (dt, J=8.4, 4.2 Hz, 1H), 1.94-2.12 (m, 4H), 1.76-1.93 (m, 1H), 1.07 (br t, J=7.1 Hz, 1H).

13C NMR (DMSO-d6) δ: 165.0, 154.0, 143.5, 142.0, 140.1, 132.8, 127.7, 126.5, 124.2, 110.7, 65.8, 62.5, 55.6, 53.3, 53.3, 29.9, 28.9, 28.8, 23.6, 16.8.

MS(ESI-TOF): 394.2071 [M+H] +.

The starting material, 1R,5S)-1-(4-bromophenyl)-3-(tetrahydro-2H-pyran-4-yl)-3-azabicyclo[3.1.0]hexan-3-ium chloride, was obtained as follows:

To a 1 L Redlay were charged (1R,5S)-1-(4-bromophenyl)-3-azabicyclo[3.1.0]hexan-3-ium chloride (30 g, 1 eq), dihydro-2H-pyran-4(3H)-one (13.13 g, 1.2 eq) and THF (300 mL). The mixture was stirred at IT=22±5° C. for 1 h. NaBH(OAc) 3 (30.1 g, 1.3 eq) was added portion wise while keeping IT<30° C. The mixture was stirred at IT=22±5° C. for 2 h. 6.2% HCl (93 g, 90 ml, 1.5 eq) was added while maintaining IT<30° C. and pH<2. The mixture was stirred for 10 min. 25% K 2CO 3 (259 g, 210 mL) was added to adjust pH=8-9. IPAc (300 mL) was added. The mixture was stirred for 10 min. After phase separation, H 2O (150 g) was added to the organic layer. The mixture was stirred for 10 min. After phase separation, the organic layer was concentrated under vacuum (50-100 mbar, 50° C. water bath). IPA (120 g, 150 mL) was added. The organic layer was concentrated under vacuum (50-100 mbar, 50° C. water bath). IPA (144 g, 180 mL) was added. The mixture was filtered through CMC. The cake was washed with IPA (24 g×2). H 2O (5 g) was added to the organic layer. 31% HCl (19.3 g) was added dropwise with IT<35° C. The mixture was stirred at IT=22±5° C. for 2 h and filtered. The cake was washed with IPA (48 g×2). The wet cake was dried under vacuum at 50° C. for at least 6 h. The desired product (31.4 g, 98% HPLC purity, 78% yield) was obtained as a white solid.

1H NMR (DMSO-d6 and D 2O) δ: 7.46 (br d, J=8.4 Hz, 2H), 7.15 (br d, J=8.4 Hz, 2H), 3.90 (br d, J=7.8 Hz, 3H), 3.62 (br s, 1H), 3.51 (br s, 2H), 3.16-3.38 (m, 3H), 2.05-2.21 (m, 1H), 1.93 (br s, 2H), 1.49-1.71 (m, 2H), 1.05-1.30 (m, 1H).

13C NMR (DMSO-d6) δ: 138.3, 131.9, 129.2, 120.4, 65.5, 62.3, 56.2, 53.9, 29.1, 28.9, 24.8, 23.0. MS(ESI-TOF): 322.0761 [M+H]+

 The complete way of manufacture of Alternative Example 34 A is depicted in the following Reaction Scheme 34A:

The first compound in this scheme, A1, can be obtained as follows:

Step 1-2 Synthesis of 1c and 1d

PAT

• Compound A [WO2021257532A1]

PAT

• example 34 [US20210155606A1]

PAT

US10710980, Example 34

PAPERS

• Discovery and Characterization of Zilurgisertib, a Potent and Selective Inhibitor of Activin Receptor-like Kinase-2 (ALK2) for the Treatment of Fibrodysplasia Ossificans ProgressivaPublication Name:ACS Medicinal Chemistry LettersPublication Date:2025-10-31PMCID:PMC12621050PMID:41256990DOI:10.1021/acsmedchemlett.5c00516
• Pharmacokinetics of Zilurgisertib With and Without Food from Single and Multiple Ascending Dose Phase 1 Studies in Healthy AdultsPublication Name:European Journal of Drug Metabolism and PharmacokineticsPublication Date:2024-12-09PMCID:PMC11802711PMID:39652202DOI:10.1007/s13318-024-00926-z

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References

1. “Atebrioz FDA label” (PDF). files.mirumpharma.com.
2. Gangat N, Tefferi A (June 2025). “Emerging Pathogenetic Mechanisms and New Drugs for Anemia in Myelofibrosis and Myelodysplastic Syndromes”. American Journal of Hematology. 100 Suppl 4: 51–65. doi:10.1002/ajh.27659. PMID 40056069.
3. Center for Drug Evaluation and Research (25 September 2026). “FDA Approves Third Treatment for Fibrodysplasia Ossificans Progressiva”. U.S. Food and Drug Administration. U.S. Food and Drug Administration (FDA). Retrieved 27 September 2026. This article incorporates text from this source, which is in the public domain.
4. “Mirum Pharmaceuticals and Incyte Announce U.S. FDA Approval of Atebrioz (zilurgisertib) for Adult and Pediatric Patients with Fibrodysplasia Ossificans Progressiva” (Press release). Mirum Pharmaceuticals. 25 September 2026. Retrieved 27 September 2026 – via Business Wire.
5. World Health Organization (2022). “International nonproprietary names for pharmaceutical substances (INN): recommended INN: list 88”. WHO Drug Information. 36 (3). hdl:10665/363551.

External links

• “Zilurgisertib ( Code – C175551 )”. EVS Explore.
• “Zilurgisertib Fumarate ( Code – C199021 )”. EVS Explore.
• Clinical trial number NCT05090891 for “To Assess the Efficacy, Safety, and Tolerability of INCB000928 in Participants With Fibrodysplasia Ossificans Progressiva (Progress)” at ClinicalTrials.gov

Clinical data
Trade names	Atebrioz
Other names	INCB-000928, INCB000928
License data	US DailyMed: Zilurgisertib
Routes of administration	By mouth
Drug class	Kinase inhibitor (ALK2 selective)
ATC code	None
Legal status
Legal status	US: ℞-only[1]
Identifiers
CAS Number	2173389-57-42173390-29-7
PubChem CID	138628908162623634
IUPHAR/BPS	11888
UNII	L5Z9S25HO21R349830SB
KEGG	D12547D12548
ChEMBL	ChEMBL5314579
Chemical and physical data
Formula	C30H38N4O3
Molar mass	502.659 g·mol−1
3D model (JSmol)	Interactive image
SMILES
InChI

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#zilurgisertib, #anax labs, #Atebrioz, #FDA 2026, #APPROVALS 2026, #L5Z9S25HO2, #INCB 000928