Important Compound Classes
Title
Cereblon Ligands and Bifunctional Compounds Comprising the Same.
Patent Application Number
WO 2019/199816 A1
Publication Date
October 17, 2019
Priority Application
US 15/953,108
Priority Date
April 13, 2018
Inventors
Crew, A. P.; Crews, C. M.; Dong, H.; Hornberger, K. R.; Wang, J.; Qian, Y.; Zimmermann, K.; Berlin, M.; Snyder, L. B.
Assignee Company
Arvinas Operations, INC., Five Science Park, New Haven, Connecticut 06511 (US).
Disease Area
Cancer
Biological Target
Cereblon (CRBN)
Summary
Lenalidomide and pomalidomide are a currently marketed class of immunomodulatory drugs which has been clinically validated as a therapeutic strategy by effecting protein degradation. These drugs are used in treatment as a consequence of their ability to promote recruitment and ubiquitination of substrate proteins to the cullin-damaged DNA-binding-RING box-domain protein (CUL4-DDB1RBX1-CRBN) E3 ubiquitin ligase. The resulting ubiquitin tagged proteins are subsequently degraded by the 26S proteasome.
Lenalidomide and pomalidomide do not promote the degradation of G1 to S phase transition 1 protein (GSPT1), which may indicate selectivity that favors the zinc finger transcription factors such as Aiolos and Ikaros. Ikaros and Aiolos (encoded by the IKZF1 and IKZF3 genes, respectively) are the first cereblon substrates identified, and their interaction with cereblon (CRBN) modulating ligands triggers their recruitment and degradation. These transcription factors play critical roles in hematological development, differentiation, and the downstream effects of protein degradations.
The potential breadth of activity of CRBN modulators has been targeted via three unrelated classes of proteins, zinc finger transition factors, protein kinases, and protein translation factors. Cereblon modulators provide an important proof-of-principle as therapeutic tools for the further development of compounds that target specific proteins for destruction that have been considered undruggable. Thalidomide, which binds to CRBN, has been approved for the treatment of a number of immunological indications, including multiple myeloma and a variety of other types of cancer. The precise mechanism of thalidomide’s antitumor activity is not well understood; however, it is known to alter the specificity of the CRBN–thalidomide complex that induces the ubiquitination and degradation of Ikaros and Aiolos transcription factors that are essential for multiple myeloma growth. Therefore, there exists the need for small molecule therapeutic agents that potentiate CRBN’s substrate specificity for a wide range of protein classes.
This Patent Highlight describes bifunctional compounds which function to recruit endogenous proteins to an E3 ubiquitin ligase for degradation. The bifunctional or PROTAC compounds comprise of an E3 ubiquitin ligase binding moiety (ULM group), a linker (L), and a moiety that binds a target protein (i.e., a protein/polypeptide targeting ligand (PTM group)) such that the target protein is placed in proximity to the ubiquitin ligase to effect degradation of that protein.
Definitions
W = CH2, CHR, C = O, SO2, NH and N-alkyl;
R1 = N, CH, CN, C1–C3 alkyl;
R2 = H or OH;
Rn = functional group or an atom;
X = H or halogen;
L = Linker comprising one or more covalently connected structural units.
Key Structures
Biological Assay
ERE Luciferase Assay, estrogen receptor-alpha (ERα) degradation assay in various cells using Western Blot method, AR ELISA Assay and BRaf in-cell Western cellular degradation assay.
Biological Data
The table below shows characterization
of representative estrogen receptor PROTAC compounds. The ER DC50 (nM), where A < 1; 1 ≤ B < 10; 10 ≤
C < 100. ER Dmax (% degraded), where
A ≥ 75; 50 ≤ B < 75.
Recent Review Articles
-
1.
Gowda C.; Song C.; Ding Y.; Iyer S.; Dhanyamraju P. K.; McGrath M.; Bamme Y.; Soliman M.; Kane S.; Payne J. L.; Doval S.. Adv. Biol. Regul. 2019, 100, 665.
-
2.
Buhimschi A. D.; Crews C. M.. Biochemistry 2019, 58, 861.
-
3.
Powell M. D.; Read K. A.; Sreekumar B. K.; Oestreich K. J.. Front. Immunol. 2019, 101, 299.
-
4.
Chen Q.; Shi Y.; Chen Y.; Ji T.; Li Y.; Yu L.. Gene 2019, 684, 47.
-
5.
Heizmann B.; Kastner P.; Chan S.. Curr. Opin. Immunol. 2018, 51, 14.
The author declares no competing financial interest.