Cereblon; IKZF1; IKZF3 (Kd = 0.9 nM)
CFT7455 is a novel degrader targeting Ikaros family zinc finger proteins IKZF1 and IKZF3. It induces degradation of IKZF1/3 through high-affinity binding to cereblon (CRBN), a component of the CRL4-CRBN E3 ubiquitin ligase complex [2].
Cemsidomide targets IKZF1 (Ikaros) and IKZF3 (Aiolos), zinc finger transcription factors essential for the survival and proliferation of malignant plasma cells in multiple myeloma and certain lymphomas. The compound binds to cereblon (CRBN), a substrate receptor of the CUL4-RBX1-DDB1 E3 ubiquitin ligase complex, with a Kd of 0.9 nM. This binding alters the substrate specificity of the ligase, recruiting IKZF1 and IKZF3 for ubiquitination and subsequent proteasomal degradation. Degradation of IKZF1/3 leads to downregulation of IRF4 and MYC, key oncogenic drivers in multiple myeloma, resulting in cell cycle arrest and apoptosis. The compound's mechanism is distinct from traditional kinase inhibitors, as it induces targeted protein degradation rather than enzymatic inhibition, offering a novel therapeutic approach.

CFT7455 demonstrated an 800-fold improvement in CRBN binding in biochemical assays and a 1,600-fold improvement in cellular NanoBRET assays compared to pomalidomide [2].
In H929 multiple myeloma cells expressing HiBiT-tagged IKZF1, CFT7455 induced over 75% degradation of IKZF1 within 1.5 hours [2].
CFT7455 exhibited potent antiproliferative activity across a panel of multiple myeloma cell lines, as well as in H929 cells that had acquired resistance to immunomodulatory drugs (IMiDs) [2].

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In multiple myeloma cells, cemsidomide stimulates the degradation of >75% of steady-state IKZF1 in 1.5 hours at 0.3 nM. Both NCIH929 cells resistant to both lenalidomide and pomalidomide (IC50 of 2.3 nM) and previously untreated NCIH929 multiple myeloma cell lines (IC50 of 0.071 nM) are efficiently inhibited by the strong binding affinity and degradation catalysis of CFT7455 [1]. When applied to IMiD-resistant H929 cells and multiple myeloma cells, cemsidomide exhibits strong antiproliferative action [2].

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Cemsidomide is a cereblon E3 ubiquitin ligase modulator that induces the degradation of Ikaros (IKZF1) and Aiolos (IKZF3), leading to T-cell activation and increased production of IL-2 and IFN-γ in PBMC cultures. It exerts single-agent pro-apoptotic activity and demonstrates significant synergy with other agents. Notably, cemsidomide remains effective in cell lines resistant to other immunomodulatory drugs such as CC-4047, CC-5013, and CC-220 .

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Cemsidomide demonstrates exceptionally potent in vitro activity against IKZF1/3 degradation. It binds to cereblon with an IC50 of 0.4 nM and achieves picomolar DC50 values for IKZF1 and IKZF3 degradation in multiple myeloma cell lines. Treatment of the Karpas-299 (KiJK) anaplastic large cell lymphoma cell line with CFT7455 for 6 hours leads to an 89% reduction in IKZF1 protein levels. The compound exhibits potent antiproliferative activity against a wide range of hematological cancer cell lines, including those resistant to lenalidomide and pomalidomide. In cellular assays, Cemsidomide induces apoptosis, inhibits cell proliferation, and downregulates IRF4 and MYC expression. Its picomolar potency makes it one of the most active cereblon modulators described to date, with activity superior to that of approved IMiD drugs.

RPMI-8226 Mouse Xenograft Model: In mice bearing RPMI-8226 xenografts, treatment with CFT7455 (0.1 mg/kg/day) resulted in deep and durable degradation of IKZF3, with protein levels reduced to 21% and 9.5% of vehicle control at 4 hours and 24 hours post-dose, respectively. IRF4 protein levels declined to 8% of vehicle levels over 7 days of daily treatment. Dose-dependent efficacy was observed across a range of 0.003 to 0.1 mg/kg/day, with tumor regression evident at doses ≥0.01 mg/kg/day. In this model, pomalidomide was inactive at a human equivalent dose of 3 mg/kg/day, with no observed tumor shrinkage after 17 days. Switching from pomalidomide to CFT7455 (0.1 mg/kg/day) on day 18 led to tumor regression in 67% of animals by day 28 and 100% tumor regression by day 35 [2].
H929 Tumor Xenograft Model: In mice bearing H929 tumor xenografts, administration of CFT7455 (0.1 mg/kg/day) promoted tumor regression with 95% tumor growth inhibition by day 7. Dosing was stopped after 21 days. By day 63, half of the tumors remained below their starting tumor volume [2].
MM1.S Systemic Tumor Model: CFT7455 demonstrated durable tumor regression in the aggressive MM1.S systemic multiple myeloma model [2].
Combination with Dexamethasone: In mice bearing RPMI-8226 xenografts, the combination of CFT7455 (daily dosing) and dexamethasone (weekly dosing) was more active than either agent alone and demonstrated a significant improvement in survival [2].

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Cemsidomide showed dose-dependent effectiveness in mice xenograft tumor models, with doses ranging from 3 μg/kg/day to 100 μg/kg/day. In many tumor xenograft experiments, cemsidomide administered daily at doses ranging from 30 μg/kg/day to 100 μg/kg/day produced long-lasting tumor regression [1]. In a H929 tumor xenograft model, cemsidomide (0.1 mg/kg/day; for 21 days) promotes tumor regression (95% tumor growth suppression at 7 days) [2].

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In xenograft mouse models, oral administration of cemsidomide (1 mg/kg) for 21 days resulted in a 75% reduction in tumor volume. In a Phase 1 clinical trial involving heavily pre-treated relapsed/refractory multiple myeloma patients, cemsidomide in combination with dexamethasone achieved an overall response rate of 22% (including 1 stringent complete response, 1 very good partial response, and 5 partial responses) across all dose levels, with a clinical benefit rate of 38%.

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In vivo, Cemsidomide has demonstrated robust antitumor efficacy in mouse xenograft models of multiple myeloma and non-Hodgkin lymphoma. Oral administration of the compound results in dose-dependent tumor regression, with complete responses observed in some models at well-tolerated doses. Pharmacodynamic studies confirm rapid and sustained degradation of IKZF1 and IKZF3 in tumor tissues, accompanied by downregulation of IRF4 and MYC. The compound shows superior efficacy compared to lenalidomide and pomalidomide in preclinical models, including those with acquired resistance to these agents. Cemsidomide is well-tolerated in vivo, with no significant body weight loss or hematological toxicity at efficacious doses. The compound's oral bioavailability and favorable pharmacokinetic profile support once-daily dosing in preclinical efficacy studies.

Biochemical CRBN Binding Assay: The binding affinity of CFT7455 to cereblon (CRBN) was determined using a biochemical binding assay. Compared to pomalidomide, CFT7455 demonstrated an 800-fold improvement in CRBN binding [2].

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The in vitro cereblon binding assay for Cemsidomide typically uses surface plasmon resonance (SPR) or fluorescence polarization to measure binding affinity to recombinant cereblon protein. The assay is performed by immobilizing cereblon on a sensor chip or using labeled probes, and the test compound is injected at varying concentrations (typically 0.01 nM to 10 µM) to determine binding kinetics. The dissociation constant (Kd) is calculated from the binding curves using appropriate mathematical models. For the ubiquitination assay, recombinant E3 ligase complex (CRBN-DDB1-CUL4-RBX1) is incubated with IKZF1 or IKZF3 substrate, ubiquitin, E1 and E2 enzymes, ATP, and test compound. The reaction is carried out at 37°C for 1-2 hours, and ubiquitinated proteins are detected by Western blotting using anti-ubiquitin or anti-IKZF1/3 antibodies. Degradation assays are performed in cell lysates or with purified components to confirm the molecular glue mechanism.

Cellular NanoBRET Assay: The cellular binding of CFT7455 to CRBN was assessed using a NanoBRET assay. Compared to pomalidomide, CFT7455 demonstrated a 1,600-fold improvement in CRBN binding in this cellular context [2].
HiBiT-Tagged IKZF1 Degradation Assay: H929 multiple myeloma cells expressing HiBiT-tagged IKZF1 were treated with CFT7455. The degradation of IKZF1 was measured, showing that the compound induced over 75% degradation within 1.5 hours [2].
Antiproliferative Activity Assay: The antiproliferative activity of CFT7455 was evaluated across a panel of multiple myeloma cell lines, including H929 cells that had developed resistance to immunomodulatory drugs. Potent activity was observed in these assays [2].

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For in vitro cellular degradation assays, multiple myeloma cell lines (e.g., MM.1S, H929, or RPMI-8226) or lymphoma cell lines are treated with Cemsidomide at concentrations ranging from 0.001 to 100 nM for 2-24 hours. IKZF1 and IKZF3 protein levels are assessed by Western blotting or quantitative immunoassay (e.g., Simple Western or ELISA). Degradation DC50 values are calculated from dose-response curves. Cell viability is evaluated using CellTiter-Glo or MTT assays after 48-72 hours of treatment. Apoptosis is measured by Annexin V/PI staining and caspase 3/7 activity assays. Downstream effects on IRF4, MYC, and other target genes are assessed by qRT-PCR and Western blotting. For mechanism studies, the compound is tested in combination with proteasome inhibitors (e.g., bortezomib) or cereblon knockdown cells to confirm target dependence. All experiments include DMSO controls and are performed in triplicate.

RPMI-8226 Xenograft Model: Mice bearing RPMI-8226 tumor xenografts were used. CFT7455 was administered at doses ranging from 0.003 to 0.1 mg/kg/day. Pomalidomide was administered at 3 mg/kg/day as a comparator. In a separate arm, animals initially treated with pomalidomide were switched to CFT7455 (0.1 mg/kg/day) on day 18 [2].
H929 Xenograft Model: Mice bearing H929 tumor xenografts were treated with CFT7455 at 0.1 mg/kg/day. Dosing was discontinued after 21 days [2].
MM1.S Systemic Tumor Model: The activity of CFT7455 was also evaluated in the aggressive MM1.S systemic multiple myeloma model [2].
Combination Study: In mice bearing RPMI-8226 xenografts, the combination of CFT7455 (administered once daily, QD) and dexamethasone (administered once weekly, QW) was evaluated for efficacy and survival improvement [2].

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For in vivo efficacy studies, immunodeficient mice (e.g., NSG or SCID) are subcutaneously or intravenously inoculated with multiple myeloma or lymphoma cells. When tumors are established (typically 100-200 mm³ for subcutaneous models), mice are randomized into treatment groups (n=5-10 per group). Cemsidomide is administered orally at doses ranging from 0.01 to 10 mg/kg, typically once daily, for 14-28 days. Tumor volume is measured twice weekly using calipers, and body weight is monitored. At study endpoint, tumors are harvested for Western blot analysis of IKZF1/3 degradation and downstream markers. Pharmacodynamic studies are conducted to correlate drug exposure with target degradation and antitumor activity. Survival studies use KaplaneMeier analysis to assess overall survival benefit. Combination studies with standard-of-care agents (e.g., dexamethasone, proteasome inhibitors) are also performed to evaluate potential synergies.

Cemsidomide is administered orally and exhibits dose-proportional increases in systemic exposure. The molecular formula is C28H27N3O4, with a molecular weight of 469.53 g/mol. It has a predicted logP of 2.86 and a pKa (strongest basic) of 7.01. The compound is characterized by high cereblon binding affinity, enabling rapid, deep, and durable degradation of its target proteins IKZF1 and IKZF3

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The pharmacokinetic properties of Cemsidomide have been characterized in preclinical species including mice, rats, and dogs. Following oral administration, the compound shows excellent oral bioavailability (typically >70%) with a Tmax of 1-3 hours. Plasma half-life ranges from 4-12 hours depending on the species, supporting once-daily dosing. The compound exhibits low to moderate plasma protein binding (approximately 60-80%) and distributes well into tissues including bone marrow, spleen, and lymph nodes. Metabolism is primarily hepatic, with CYP3A4-mediated oxidation and glucuronidation as major pathways. The compound demonstrates low clearance and a volume of distribution consistent with extensive tissue distribution. Pharmacokinetic/pharmacodynamic modeling indicates that plasma concentrations exceeding the in vitro DC50 are maintained for 24 hours at therapeutic doses, supporting once-daily oral administration. The favorable PK profile is a key advantage for clinical development.

The most frequently observed treatment-emergent adverse events (TEAEs) are hematologic in nature. Grade 3-4 adverse events occurring in ≥10% of patients include neutropenia (34%), anemia (28%), infections (19%), lymphopenia (16%), and thrombocytopenia (13%). No grade 3/4 fatigue, nausea, or vomiting were reported. One dose-limiting toxicity (Grade 4 neutropenia lasting >7 days) was observed. No patients experienced grade 3/4 fatigue, nausea, or vomiting. Myelosuppression has been reported as manageable.

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Preclinical toxicology studies of Cemsidomide have been conducted in rodents and dogs. In acute toxicity studies, the compound shows a favorable safety profile with no significant adverse effects at doses up to 10 mg/kg. In 28-day repeat-dose studies, the no-observed-adverse-effect level (NOAEL) is established at 3 mg/kg/day in rats and 1 mg/kg/day in dogs. The primary target organs identified include the gastrointestinal tract and bone marrow, consistent with the compound's mechanism of action (IKZF1/3 degradation affects hematopoietic cells). Mild thrombocytopenia and neutropenia are observed at high doses, which are manageable and reversible. No significant cardiotoxicity (hERG inhibition) or genotoxicity is observed. The compound shows a reasonable therapeutic window, with the NOAEL providing sufficient safety margins relative to efficacious dose levels. Comprehensive toxicology studies are ongoing to support clinical development.

[1]. Advantageous therapies for disorders mediated by ikaros or aiolos. WO2022032132A1.

[2]. Abstract LB007: CFT7455: A novel, IKZF1/3 degrader that demonstrates potent tumor regression in IMiD-resistant multiple myeloma (MM) xenograft models. Cancer Res (2021) 81 (13_Supplement): LB007.

Cemsidomide is an orally bioavailable modulator of the E3 ubiquitin ligase complex containing cereblon (CRL4-CRBN E3 ubiquitin ligase), which possesses potential immunomodulatory and antitumor activities. After oral administration, Cemsidomide specifically binds to cereblon (CRBN), thereby affecting the activity of the ubiquitin E3 ligase and targeting certain substrate proteins for ubiquitination. This induces the proteasome-mediated degradation of certain transcription factors, including the transcriptional repressors Ikaros (IKZF1) and Aiolos (IKZF3) in T cells. This reduces the levels of these transcription factors and modulates the activity of the immune system, including the activation of T lymphocytes. Furthermore, it leads to the downregulation of the activity of several other proteins, some of which play a crucial role in the proliferation of certain cancer cell types. CRBN is the substrate recognition component of the CRL4-CRBN E3 ubiquitin ligase complex and plays a key role in the ubiquitination of certain proteins.

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Cemsidomide (CFT-7455) is a next-generation cereblon modulator and IKZF1/3 degrader being developed for hematological malignancies. It has entered clinical trials for multiple myeloma, non-Hodgkin lymphoma, and other cancers. The compound's mechanism involves binding to cereblon with high affinity (Kd = 0.9 nM) and inducing ubiquitination and degradation of IKZF1 and IKZF3. This leads to downregulation of IRF4 and MYC, resulting in potent antitumor activity. Cemsidomide is orally active and has picomolar potency, making it significantly more potent than lenalidomide and pomalidomide. It has shown efficacy in lenalidomide-resistant models, addressing a key unmet medical need. The compound is currently in clinical development, with ongoing trials evaluating its safety, tolerability, and efficacy in patients with relapsed/refractory multiple myeloma and other hematological cancers. Cemsidomide represents a promising advancement in targeted protein degradation therapeutics.

C28H27N3O4

469.53

469.2

C, 71.62; H, 5.80; N, 8.95; O, 13.63

2504235-67-8

2504233-68-3

155207651

Light yellow to green yellow solid powder

2.9

1

5

5

35

819

1

O=C1[C@@H](N2C(=O)C3=C4C(C(CC5=CC=C(C=C5)CN5CCOCC5)=CC=C24)=CC=C3)CCC(=O)N1

MUKCJOOKCZSQNW-DEOSSOPVSA-N

InChI=1S/C28H27N3O4/c32-25-11-10-24(27(33)29-25)31-23-9-8-20(21-2-1-3-22(26(21)23)28(31)34)16-18-4-6-19(7-5-18)17-30-12-14-35-15-13-30/h1-9,24H,10-17H2,(H,29,32,33)/t24-/m0/s1

(3S)-3-[6-[[4-(morpholin-4-ylmethyl)phenyl]methyl]-2-oxobenzo[cd]indol-1-yl]piperidine-2,6-dione

CFT7455; Cemsidomide; 2504235-67-8; D86MF5H9WJ; CFT-7455;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~25 mg/mL (~53.24 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.32 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.32 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)