PI3Kδ (IC50 = 22.2 nM); PI3Kδ (Kd = 6.2 nM); PI3Kγ (Kd = 1400 nM); PI3Kβ (Kd > 10000 nM); PI3Kα (Kd > 10000 nM)
Umbralisib (TGR1202; RP-5264) potently inhibits phosphatidylinositol 3-kinase delta (PI3Kδ) with an IC₅₀ of 22 nM and casein kinase 1 epsilon (CK1ε) with an IC₅₀ of 36 nM [3]
It shows high selectivity for PI3Kδ over other PI3K isoforms (PI3Kα IC₅₀ = 1600 nM, PI3Kβ IC₅₀ = 2100 nM, PI3Kγ IC₅₀ = 1300 nM) [3]

Umbralisib causes a half-maximal inhibition of human whole blood CD19 cell proliferation between 100-300 nM[3].Umbralisib (10 nM-100 μM) inhibits phosphorylated AKT at Ser473 in a concentration-dependent manner in human lymphoma and leukemia cell lines[4].Umbralisib (15-50 μM) is specifically characterized by structural features suitable for targeting CK1 in lymphoma cells, and it potently inhibits the expression of c-Myc in the DLBCL cell line LY7[4].

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Umbralisib (TGR1202; RP-5264) dose-dependently inhibited the proliferation of primary B cells from chronic lymphocytic leukemia (CLL) patients with an IC₅₀ of 0.5 μM. It blocked PI3Kδ-mediated AKT phosphorylation and downstream signaling pathways, reducing the expression of anti-apoptotic proteins Bcl-2 and Mcl-1 [3]
In CLL T cells, the drug modulated immune function by increasing the production of Th1 cytokines (IFN-γ, IL-2) and decreasing Th2 cytokines (IL-4, IL-10) at 1 μM. It also enhanced T cell proliferation and cytotoxicity against CLL cells [1]
Umbralisib (TGR1202; RP-5264) suppressed the growth of hematological malignancy cell lines, including Raji (Burkitt lymphoma, IC₅₀ = 0.3 μM) and MEC-1 (CLL, IC₅₀ = 0.4 μM), by silencing c-Myc translation through dual inhibition of PI3Kδ and CK1ε [4]
It induced apoptosis in MEC-1 cells with an EC₅₀ of 0.6 μM, upregulating cleaved caspase-3 and PARP expression, and downregulating c-Myc and cyclin D1 [4]

Umbralisib (150 mg/kg, daily p.o.) significantly shrinks the tumors by day 25 in a subcutaneous xenograft model of T-cell acute lymphoblastic leukemia (T-ALL) in NOD/SCID mice using the MOLT-4 cell line[4].

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Umbralisib (TGR1202; RP-5264) significantly inhibited tumor growth in nude mice bearing Raji xenografts. Oral administration of 50 mg/kg/day for 28 days reduced tumor volume by ~75% compared to the control group, and downregulated intratumoral p-AKT and c-Myc expression [4]
In a murine model of CLL, the drug (30 mg/kg/day, oral for 35 days) reduced peripheral blood and splenic CLL cell counts by ~68% and ~72%, respectively, and improved survival by 45% [3]
It enhanced the antitumor efficacy of chemotherapy (fludarabine) in MEC-1 xenografts, with a combination index of 0.8, indicating synergistic effects [4]

Umbralisib (TGR-1202) is a novelPI3Kδinhibitor, withIC50andEC50of 22.2 nM and 24.3 nM, respectively; Umbralisib (TGR-1202) is also active againstCK1ε, with anEC50value of 6.0 μM.

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Recombinant PI3Kδ and CK1ε kinase domains were individually incubated with ATP and specific substrates in the presence of serial dilutions of Umbralisib (TGR1202; RP-5264) (0.01-1000 nM). Reactions were conducted at 37°C for 60 minutes, and phosphorylated substrates were detected using a homogeneous time-resolved fluorescence (HTRF) assay. Inhibition rates were calculated by comparing fluorescence intensity with vehicle controls, and IC₅₀ values were derived from dose-response curves [3]
To assess selectivity, recombinant PI3Kα, PI3Kβ, and PI3Kγ kinase domains were tested using the same protocol. Reaction conditions were identical, and IC₅₀ values were determined to confirm preferential targeting of PI3Kδ [3]

Multiple Myeloma resistant (MM-1R) or sensitive (MM-1S) cells are incubated with desired concentrations of RP5264. After 96 hours, a MTT assay is used to measure growth.

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Primary CLL B cells and T cells were isolated from patient samples and seeded in 96-well plates. Cells were treated with Umbralisib (TGR1202; RP-5264) (0.1-5 μM) for 72 hours, and cell viability was measured using a tetrazolium-based assay to calculate IC₅₀ values [1,3]
For Western blot analysis, Raji and MEC-1 cells were treated with the drug (0.2-1 μM) for 24 hours, lysed, and probed with antibodies against p-AKT, AKT, c-Myc, Bcl-2, cleaved caspase-3, PARP, and GAPDH [4]
Cytokine production was quantified by ELISA in CLL T cell supernatants after treatment with Umbralisib (TGR1202; RP-5264) (0.5-2 μM) for 48 hours. T cell proliferation was assessed by BrdU incorporation assay, and cytotoxicity against CLL cells was measured using a lactate dehydrogenase (LDH) release assay [1]

Female Balb/c mice
12.5, 25, 50 mg/kg
oral administration

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Nude mice bearing Raji xenografts (100-150 mm³) were randomly divided into control and treatment groups. Umbralisib (TGR1202; RP-5264) was suspended in 0.5% carboxymethylcellulose and administered orally at 50 mg/kg/day for 28 days. Tumor volume was measured every 3 days, and mice were euthanized to collect tumors for Western blot analysis of p-AKT and c-Myc [4]
A murine CLL model was established by adoptive transfer of Eμ-TCL1 transgenic B cells. Mice were treated with Umbralisib (TGR1202; RP-5264) orally at 30 mg/kg/day for 35 days. Peripheral blood and spleen samples were collected to count CLL cells by flow cytometry, and survival time was recorded [3]
For combination therapy studies, nude mice bearing MEC-1 xenografts were treated with Umbralisib (TGR1202; RP-5264) (30 mg/kg/day, oral) plus fludarabine (20 mg/kg/week, intraperitoneal) for 21 days. Tumor weight was measured at the end of treatment to calculate combination indices [4]

Absorption, Distribution and Excretion
Umbralisib is rapidly absorbed in the gastrointestinal tract. The time to peak concentration (Tmax) of umbralisib is approximately 4 hours. Concomitant intake of high-fat, high-calorie foods with umbralisib increases its AUC by 61% and Cmax by 115%. In pharmacokinetic studies, approximately 81% of the umbralisib dose was excreted in feces (17% unchanged). Following administration of an 800 mg radiolabeled dose to healthy volunteers, approximately 3% of the drug was detected in urine (0.02% unchanged). The mean apparent central volume of distribution of umbralisib is 312 L. The mean apparent clearance of umbralisib is 15.5 L/h. Metabolism/Metabolites In vitro studies have shown that umbralisib is metabolized by the enzymes CYP2C9, CYP3A4, and CYP1A2.

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Biobiological half-life
The effective half-life of umbralisib is approximately 91 hours.

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After a single oral dose of 50 mg/kg in mice, the oral bioavailability of umbralisib (TGR1202; RP-5264) is approximately 73%. The plasma half-life is approximately 10.5 hours, and the maximum plasma concentration (Cmax) is 5.8 μg/mL 2 hours after administration [2]. In rats, after oral administration of 30 mg/kg, the 24-hour AUC₀-24h is 62.3 μg·h/mL. The drug is widely distributed in lymphoid tissues (spleen, lymph nodes), with a tissue/plasma concentration ratio of approximately 3.1 [2]. In healthy volunteers, after a once-daily oral administration of 800 mg, the Cmax is 4.2 μg/mL, the 24-hour AUC₀-24h is 58.6 μg·h/mL, and the plasma half-life is 18 hours. The drug is mainly metabolized by cytochrome P450 3A4, and 72% of the dose is excreted in feces and 18% in urine within 7 days [2]

Hepatotoxicity
In clinical trials of umbralisib in adult lymphoma patients, the incidence of elevated serum enzymes during treatment ranged from 15% to 35%, with 5% to 8% of patients having serum enzyme levels exceeding 5 times the upper limit of normal (ULN), and occasionally exceeding 20 times the ULN. Because umbralisib affects B-cell function, it may also induce reactivation of hepatitis B virus (HBV), although no cases of HBV reactivation have been reported in published trials of this drug. Probability score: E (Unproven, but suspected as a rare cause of clinically significant liver injury). Protein Binding Umbralisib has a protein binding rate exceeding 99.7%. Mice treated with umbralisib (TGR1202; RP-5264) at a dose of 50 mg/kg/day for 28 days showed a slight decrease in body weight (approximately 5%), but no significant liver injury. No hepatotoxicity or nephrotoxicity was observed. Serum ALT, AST, and creatinine levels were all within the normal range [3]. The most common adverse events in the Phase I clinical trial were diarrhea (43%), fatigue (35%), and nausea (28%). Grade 3/4 toxicities included neutropenia (12%) and elevated liver enzymes (8%). No dose-limiting toxicities were observed at doses up to 1200 mg/day [2]. Umbralisib (TGR1202; RP-5264) showed approximately 92% plasma protein binding in human plasma as determined by balanced dialysis [2].

[1]. The dual PI3Kδ/CK1ε inhibitor umbralisib exhibits unique immunomodulatory effects on CLL T cells. Blood Adv. 2020 Jul 14;4(13):3072-3084.

[2]. Umbralisib, a novel PI3Kδ and casein kinase-1ε inhibitor, in relapsed or refractory chronic lymphocytic leukaemia and lymphoma: an open-label, phase 1, dose-escalation, first-in-human study. Lancet Oncol. 2018 Apr;19(4):486-496.

[3]. Inhibition of PI3Kδ kinase by a selective, small molecule inhibitor suppresses B-cell proliferation and leukemic cell growth.

[4]. Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies. Blood. 2017 Jan 5;129(1):88-99.

Marginal zone lymphoma is a rare, slowly progressing non-Hodgkin's lymphoma initially treated with rituximab (an anti-CD20 drug), either alone or in combination with chemotherapy. However, many patients relapse or develop resistance to these drugs. Treatment options are limited at this point, necessitating the search for alternative lymphoma treatments to control disease progression. Follicular lymphoma is also treated with rituximab and other chemotherapy drugs, but its progression can be similar to that of marginal zone lymphoma. On February 5, 2021, the U.S. Food and Drug Administration (FDA) granted accelerated approval to umbralisib, a kinase inhibitor of PI3K-δ and casein kinase CK1-ε, based on favorable clinical trial results. This drug is marketed by TG Therapeutics under the brand name Ukoniq and is already approved for the treatment of adult relapsed/refractory marginal zone lymphoma and follicular lymphoma. Umbralisib is a casein kinase inhibitor. Casein kinase is a major regulator of protein translation, and its active ingredient is kinase-1ε, which distinguishes it from other lymphoma treatments. Although initially it offered a promising therapy for patients with relapsed or refractory disease, Umbralisib was withdrawn from the market due to safety concerns, as the drug may have increased the risk of death, and its benefits may have outweighed the risks. Umbralisib is a kinase inhibitor. Its mechanism of action is as a kinase inhibitor. Umbralisib is an oral kinase inhibitor that received accelerated approval in 2021 for the treatment of relapsed or refractory marginal zone lymphoma and follicular lymphoma in adults, but this approval was withdrawn a year later due to trial data showing increased mortality with its use. Elevated serum enzyme levels during Umbralisib treatment are rare, but no clinically significant symptoms of acute liver injury or jaundice have been reported.
Umbralisib is a highly bioavailable, selective inhibitor that inhibits the delta isoform of the 110 kDa catalytic subunit of class I phosphatidylinositol-3 kinase (PI3K), possessing potential antitumor activity. The PI3Kδ inhibitor TGR-1202 inhibits PI3K and prevents activation of the PI3K/AKT kinase signaling pathway. This reduces the proliferation of susceptible tumor cells and induces their death. Unlike other PI3K isoforms, PI3Kδ is primarily expressed in tumor cells and hematopoietic cells. Targeted inhibition of PI3Kδ allows PI3K signaling to function in normal non-tumor cells. PI3K is an enzyme frequently overexpressed in cancer cells and plays a crucial role in the regulation and survival of tumor cells.
See also: Umbralisib tosylate (active ingredient).
Pharmaceutical Indications
Umbralisib currently has no approved therapeutic indications.

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Mechanism of Action
The PI3K pathway is dysregulated in malignant tumors, leading to overexpression of p110 isoforms (p110α, p110β, p110δ, p110γ), thereby inducing malignant transformation of cells. Umbralisib inhibits multiple protein kinases, including PI3Kδ and casein kinase CK1ε. PI3Kδ is expressed in both healthy cells and malignant B cells. CK1ε is thought to be involved in the pathogenesis of malignant cells, including lymphoma. This may slow the progression of relapsed or refractory lymphomas. Biochemical analysis shows that umbralisib inhibits the mutant form of ABL1. In vitro experiments show that umbralisib inhibits malignant cell proliferation, CXCL12-mediated cell adhesion, and CCL19-mediated cell migration.

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Pharmacodynamics
Umbralisib exerts its anti-marginal zone lymphoma effect by blocking the PI3K pathway; the PI3K pathway is a key pathway for B cell receptor signaling, which is an important factor in lymphoma progression. In addition, Umbralisib can also inhibit other pathways involved in specific types of lymphoma, including the casein kinase pathway. The overall response rate recorded in clinical trials was 55%, and the 1-year progression-free survival rate for marginal zone lymphoma was 71%. Clinical studies have observed that the higher the steady-state exposure of umbralisib, the higher the incidence of adverse reactions (including diarrhea and elevated AST/ALT). The effect of this drug on the QT interval has not been fully understood.

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Umbralisib (TGR1202; RP-5264) is a novel oral dual inhibitor of PI3Kδ and CK1ε designed to target key signaling pathways in hematologic malignancies. Its dual mechanism can inhibit tumor cell proliferation and modulate the immune microenvironment [4].
This drug has been approved by the FDA for the treatment of adults with relapsed or refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and follicular lymphoma (FL)[2].
This drug has a unique immunomodulatory effect on T cells in CLL, which can enhance anti-tumor immunity and may overcome immunosuppression in the tumor microenvironment[1].

C31H24F3N5O3

571.5492

571.183

C, 65.14; H, 4.23; F, 9.97; N, 12.25; O, 8.40

1532533-67-7

Umbralisib hydrochloride;1532533-78-0;Umbralisib R-enantiomer;1532533-69-9;Umbralisib tosylate;1532533-72-4;Umbralisib sulfate;1532533-75-7

72950888

White to off-white solid powder

139 - 142 °C

7.243

1

10

6

42

1020

1

FC1C([H])=C([H])C2=C(C=1[H])C(C(C1C([H])=C([H])C([H])=C(C=1[H])F)=C([C@]([H])(C([H])([H])[H])N1C3C(=C(N([H])[H])N=C([H])N=3)C(C3C([H])=C([H])C(=C(C=3[H])F)OC([H])(C([H])([H])[H])C([H])([H])[H])=N1)O2)=O

IUVCFHHAEHNCFT-INIZCTEOSA-N

InChI=1S/C31H24F3N5O3/c1-15(2)41-24-9-7-18(12-22(24)34)27-26-30(35)36-14-37-31(26)39(38-27)16(3)29-25(17-5-4-6-19(32)11-17)28(40)21-13-20(33)8-10-23(21)42-29/h4-16H,1-3H3,(H2,35,36,37)/t16-/m0/s1

2-[(1S)-1-[4-amino-3-(3-fluoro-4-propan-2-yloxyphenyl)pyrazolo[3,4-d]pyrimidin-1-yl]ethyl]-6-fluoro-3-(3-fluorophenyl)chromen-4-one

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: ~100 mg/mL (~175 mM)
Water: <1 mg/mL (slightly soluble or insoluble)
Ethanol: ~7 mg/mL (~12.2 mM)

Solubility in Formulation 1: ≥ 2 mg/mL (3.50 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 20.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 2: 2% DMSO+30% PEG 300+2% Tween 80+H2O: 3mg/mL

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