Cited by 137Protein Degradation and InhibitorsMultiple Myeloma Research and TreatmentsUbiquitin and proteasome pathways

The DOI matches its Crossref record; 240 of the 240 references it cites were found in a registry or an index; 12 of the 277 sources its claims cite were checked for support.

Cancer therapies based on targeted protein degradation — lessons learned with lenalidomide

Open access
Jan, Max, Sperling, Adam S., Ebert, Benjamin L.·2021·Nature Reviews Clinical Oncology

Abstract

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of ‘degrader’ drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies. The discovery that the anticancer activity of thalidomide and its analogues, such as lenalidomide, reflects drug-induced degradation of specific target proteins has heightened interest in novel ‘degrader’ drugs. Herein, the authors review the wide and expanding use of thalidomide analogues in the treatment of multiple cancers and outline how lessons learned from this experience, particularly with lenalidomide, can guide the clinical development of new targeted protein degradation platforms. Thalidomide analogues including lenalidomide and pomalidomide are anticancer agents used in the treatment of multiple haematological malignancies; induction of targeted protein degradation of disease-relevant proteins is the dominant mechanism of action of these agents. ‘Degrader’ therapeutics have a catalytic, event-driven pharmacology, and their biological effects are a summation of the polypharmacology of multiple degraded neosubstrate proteins. Cancers acquire resistance to thalidomide analogues by circumventing target protein degradation or by rewiring pathways downstream of target protein degradation. Quantitative clinical proteomic assays can be used for pharmacodynamic monitoring of degrader therapeutics. Molecular switches gated by degrader therapeutics can be used to control genetically engineered adoptive cell products that are being developed for anticancer immunotherapy. Multiple classes of degrader therapeutics are expanding the druggable proteome to include previously undruggable, noncatalytic, cancer-relevant proteins, such as transcription factors, mRNA-splicing factors and cyclins. Thalidomide analogues including lenalidomide and pomalidomide are anticancer agents used in the treatment of multiple haematological malignancies; induction of targeted protein degradation of disease-relevant proteins is the dominant mechanism of action of these agents. ‘Degrader’ therapeutics have a catalytic, event-driven pharmacology, and their biological effects are a summation of the polypharmacology of multiple degraded neosubstrate proteins. Cancers acquire resistance to thalidomide analogues by circumventing target protein degradation or by rewiring pathways downstream of target protein degradation. Quantitative clinical proteomic assays can be used for pharmacodynamic monitoring of degrader therapeutics. Molecular switches gated by degrader therapeutics can be used to control genetically engineered adoptive cell products that are being developed for anticancer immunotherapy. Multiple classes of degrader therapeutics are expanding the druggable proteome to include previously undruggable, noncatalytic, cancer-relevant proteins, such as transcription factors, mRNA-splicing factors and cyclins.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This review uses lenalidomide and other thalidomide analogues as a clinical template for targeted protein degradation, covering molecular glue mechanisms, approved oncology uses, resistance, toxicities, and next-generation degraders. It argues that decades of IMiD experience provide key lessons for developing new degraders against previously undruggable proteins.

Key findings

  • Thalidomide analogues act as molecular glues that recruit neosubstrates to CRL4^CRBN for ubiquitination and proteasomal degradation; lenalidomide degrades IKZF1/IKZF3 in multiple myeloma and CK1α in del(5q) MDS.
  • Clinical activity is broad: lenalidomide plus dexamethasone produced ORRs up to 90% in newly diagnosed MM and superior 4-year OS versus melphalan–thalidomide–prednisone (59% versus 51%; HR 0.78, p=0.02); in relapsed/refractory MCL, lenalidomide improved median PFS versus investigator’s choice (8.7 versus 5.2 months; HR 0.61; p=0.004); in del(5q) MDS, ORRs were 76–83% with cytogenetic CR in 45–50%.
  • Resistance can arise through CRBN pathway alterations, including CRBN mutations in up to a third of pomalidomide-refractory disease, substrate competition, and downstream escape such as TP53 mutations in del(5q) MDS.
  • Toxicities include grade 3/4 neutropenia (28%) and thrombocytopenia (8%), second primary malignancies with lenalidomide maintenance (5.3% versus 0.8% with placebo/observation), and venous thromboembolism (OR 3.51; p<0.001); next-generation agents include avadomide, iberdomide, CC-92480, and CC-90009.

Methods

  • Narrative review of thalidomide analogues and targeted protein degradation, synthesizing mechanistic, preclinical, and clinical literature rather than reporting a new primary study.
  • Data sources are published clinical trials and mechanistic studies across MM, NHL, MDS, AML, KS, and related malignancies; no new patient cohort or systematic search strategy is described.
  • Main analysis is a conceptual and clinical synthesis of degrader pharmacology, resistance mechanisms, toxicities, and emerging therapeutic platforms, including PROTACs and molecular glue degraders.

Limitations

  • The paper does not explicitly state limitations of the review itself.
  • Evident from the text: it is a narrative review without a described systematic search strategy or formal evidence-quality appraisal, so selection and interpretation of cited literature may be subject to bias.
  • The authors also note field limitations: clinical pharmacodynamic monitoring has been limited by semi-quantitative protein detection and limited deployment of such assays, and quantitative proteomic datasets from clinical specimens are currently lacking.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41571-021-00479-z

Cites

240 of 240 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

153 Not checked yet · 19 Own interpretation · 7 No basis given · 2 Partly supported · 1 Not supported · accuracy not yet measured

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Show all 99 claims

  • It may state two separate claims as one. 71
  • Probably not a substantial claim. 15
  • The quote only partly states this claim. 1
83 of 83
  • The authors state this as an assumption.

    The teratogenic effect is common to all thalidomide analogues.

    “Nevertheless, this adverse effect is assumed to be common to all thalidomide analogues, and appropriate precautions are recommended for all drugs of this class.”
  • The paper relies on this without support.

    Transcription factors, scaffolding proteins and other proteins central to cancer biology typically lack catalytic activity and have remained mostly recalcitrant to drug development.

    “Novel approaches are required, however, to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development.”
  • The paper relies on this without support.

    Many degraded neosubstrates, such as zinc finger transcription factors, do not contain ligand-binding sites that could be targeted using traditional therapeutic agents.

    “Many of the degraded neosubstrates, such as zinc finger transcription factors, do not contain ligand-binding sites that could be targeted using traditional therapeutic agents.”
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Metadata

Authors
Jan, M., Sperling, A. S., & Ebert, B. L.
Affiliations
Broad Institute (US)
Corresponding author
Ebert, Benjamin L.
Venue
Nature Reviews Clinical Oncology
Published
2021-03-02
Volume
18
Issue
7
Pages
401-417
ISSN
  • 1759-4774 (ISSN-L)
  • 1759-4782
OpenAlex
W3135294709
Cited by
137
References
240
Citations by year
2026: 16 · 2025: 33 · 2024: 21 · 2023: 33 · 2022: 23 · 2021: 11
FWCI
2.31
Type
journal article
Language
en
Open access
Locations
  • Nature Reviews Clinical Oncology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Howard Hughes Medical Institute
  • European Hematology Association (TRTH160)
  • National Heart, Lung, and Blood Institute (R01HL082945)
  • National Cancer Institute (K08CA252174, R35CA253125, P01CA108631, P50CA206963, T32CA009216, P01CA066996)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Degradation and Inhibitors
  • Health Sciences › Medicine › Hematology › Multiple Myeloma Research and Treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ubiquitin and proteasome pathways
Keywords
targeted protein degradation, lenalidomide, thalidomide analogues, E3 ubiquitin ligase, proteasomal degradation, undruggable proteins, druggable proteome, fulvestrant, pomalidomide, hematologic malignancies, resistance mechanisms, clinical development
MeSH terms
Drug Development, Lenalidomide, Animals, Antineoplastic Agents, Humans, Neoplasms, Drugs, Investigational, Proteome, Molecular Targeted Therapy, Proteolysis

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