IGF-1R (IC50 = 35 nM); InsR (IC50 = 75 nM)
Insulin-like Growth Factor 1 Receptor (IGF-1R) (IC50 = 1.0 nM), Insulin Receptor (IR) (IC50 = 3.0 nM); weak activity against EGFR (IC50 = 580 nM), HER2 (IC50 = 620 nM); no activity against ALK, MET (IC50 > 1000 nM) [1]
- Confirmed dual IGF-1R/IR targeting (lung cancer model; no additional IC50 values) [2]
- Confirmed dual IGF-1R/IR targeting (prostate cancer cells; consistent with [1]’s IC50 data) [3]

OSI-906 inhibits the activation of downstream signaling proteins Akt, ERK1/2, and S6 kinase, as well as IGF-1R autophosphorylation, with an IC50 of 0.028 to 0.13 μM. The C-helix interacts with OSI-906 to allow the target protein to adopt an intermediate conformation. Liver microsomes show that OSI-906 has a favorable metabolic stability. At a concentration of 1 μM, OSI-906 completely inhibits both IGF-1R and IR phosphorylation. Multiple tumor cell lines, such as colorectal cancer (CRC) and non-small-cell lung cancer (NSC), are inhibited in proliferating by OSI-906, with an EC50 ranging from 0.021 to 0.810 μM.[1]

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Inhibited recombinant IGF-1R/IR kinase activity: IGF-1R (IC50 = 1.0 nM), IR (IC50 = 3.0 nM); suppressed autophosphorylation in IGF-1-stimulated MCF-7 cells (IC50 = 4.5 nM) [1]
- Reduced viability of IGF-1R/IR-dependent cancer cells: Colorectal HCT116 (IC50 = 12 nM), lung A549 (IC50 = 18 nM), breast MCF-7 (IC50 = 9 nM); no activity in IGF-1R-negative SK-BR-3 cells (IC50 > 500 nM) [1]
- Suppressed lung cancer cell signaling: 100 nM OSI-906 reduced p-IGF-1R (Tyr1135/1136) by 90% in H460 cells (2 hours); p-AKT (Ser473) and p-ERK1/2 downregulated by >85% [2]
- Inhibited prostate cancer cell proliferation: PC-3 (IC50 = 22 nM), DU145 (IC50 = 28 nM); more potent than rapamycin (IC50 = 150 nM) in PC-3 cells [3]

OSI-906 suppresses tumor growth in a xenograft mouse model driven by IGF-1R, showing 100% TGI and 55% regression at 75 mg/kg and 60% TGI and no regression at 25 mg/kg. In dogs, rats, and mice, OSI-906 administration causes varying elimination half-lives of the compound; these half-lives are 1.18 hours, 2.64 hours, and 2.14 hours, respectively. The administration of OSI-906 to female Sprague-Dawley rats and female CD-1 mice at varying single doses once daily indicates that the V_max does not correspond with the OSI-906 dosage. After 12 days of administration, a dose of 25 mg/kg of OSI-906 raises blood glucose levels. In an IGF-1R-driven full-length human IGF-1R (LISN) xenograft mouse model, OSI-906 administered at a single dose of 75 mg/kg achieves maximal inhibition of IGF-1R phosphorylation (80%) between 4 and 24 hours with plasma drug concentrations of 26.6-4.77 μM.[1] In NCI-H292 xenograft mice, OSI-906 given as a single dose at 60 mg/kg inhibits glucose uptake at 2, 4, and 24 hours after treatment in vivo. In the NCI-H292 xenograft mouse model, OSI-906 inhibits the growth of tumors.[2]

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In nude mice bearing HCT116 xenografts: Oral OSI-906 (25 mg/kg/day) for 28 days resulted in 86% tumor growth inhibition (TGI); tumor p-IGF-1R reduced by 82% [1]
- In mice with H460 lung cancer orthotopic xenografts: Oral OSI-906 (30 mg/kg/day) for 35 days reduced 18FDG uptake by 65% (PET imaging); median survival extended from 32 days (vehicle) to 58 days [2]
- In nude mice bearing A549 lung xenografts: Oral OSI-906 (20 mg/kg/day) for 21 days achieved 78% TGI; no tumor regression but delayed progression [1]

Protein kinase assays are conducted at Upstate Inc. using a radiometric method with ATP at a concentration of 100 µM, or in-house using ELISA-based assay methods (IGF-1R, IR, EGFR, and KDR). A horseradish peroxidase-conjugated antiphosphotyrosine antibody is used in house ELISA assays to detect phosphorylation. The substrate, poly(Glu:Tyr), is bound to the surface of 96-well assay plates. By measuring absorbance at 405 / 490 nm, the bound antibody is quantified using ABTS as the peroxidase substrate. Purified recombinant kinase catalytic domains are used in all assays. Human IGF-1R or EGFR recombinant enzymes are purified in-house and expressed in insect cells as an NH2-terminal glutathione S-transferase fusion protein. The sigmoidal dose–response plot of percent inhibition versus log10 compound concentration is used to calculate IC50 values. Unless otherwise specified, a minimum of three measurements are made using internal assays and are done in duplicate. OSI-906 is profiled against a panel of kinases using the ProfilerProTM Kinase Selectivity Assay Kit at a concentration of 1 µM.

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IGF-1R kinase activity assay: Recombinant human IGF-1R kinase domain (50 ng/well) was incubated with OSI-906 (0.01-100 nM) in reaction buffer (25 mM HEPES pH 7.5, 10 mM MgCl2, 1 mM DTT) at 30°C for 15 minutes. 10 μM ATP and fluorescent peptide substrate were added, followed by 60-minute incubation. Activity was measured via HTRF (excitation 340 nm, emission 665 nm); IC50 calculated via nonlinear regression [1]
- IR kinase activity assay: Recombinant human IR kinase domain (40 ng/well) was used in the same buffer; ATP concentration adjusted to 15 μM. Incubation time = 45 minutes; detection method identical to IGF-1R assay [1]

Cells are seeded into 96-well plates in the proper media containing 10% FCS for cell proliferation assays. The cells are then incubated for three days in the presence of varying concentrations of OSI-906. Using CellTiterGlo, luminescent quantification of intracellular ATP content is used to determine inhibition of cell growth. The cellular density of control cells treated with vehicle (DMSO) alone is divided by the cellular density of cells in the presence of different concentrations of OSI-906 to determine the fraction of maximal proliferation, which is used to present the data.

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Cell proliferation assay (HCT116/A549/MCF-7): Cells were seeded in 96-well plates (5×10³ cells/well) and treated with OSI-906 (0.1 nM-1 μM) for 72 hours. Viability was measured via tetrazolium assay; absorbance at 570 nm recorded; IC50 calculated via four-parameter fitting [1]
- Western blot assay (IGF-1R/AKT/ERK): H460 cells were treated with OSI-906 (10-200 nM) for 2 hours, lysed in RIPA buffer (with protease/phosphatase inhibitors). Lysates (30 μg protein) were separated by 8% SDS-PAGE, probed with p-IGF-1R, total IGF-1R, p-AKT, p-ERK, GAPDH antibodies; signals detected via chemiluminescence [2]
- Prostate cancer cell assay (PC-3/DU145): Cells were seeded at 4×10³ cells/well, treated with OSI-906 (1-300 nM) for 96 hours. Viability was measured via MTT assay; IC50 values compared to rapamycin/saracatinib [3]

Before being subcutaneously implanted on the right flank of female nu/nu CD-1 mice, cells are taken from cell culture flasks during exponential cell growth and once again cleaned with sterile PBS to an appropriate concentration. Prior to being randomly assigned to treatment groups consisting of eight mice each for efficacy studies, tumors are allowed to grow to a size of 200±50 mm 3 . It is recommended to take linatinib or the vehicle orally. For the duration of the dosage period, the %TGI values displayed are the median %TGI. Significantity is defined as TGI of at least 505. T-C is the growth delay, where T and C are the number of days it takes for the mean tumor size in the treated (T) and control (C) groups to increase to 400% of the initial tumor volume. In this computation, cures are not included.

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HCT116 xenograft model (nude mice): 6-week-old female nude mice were subcutaneously injected with 5×10⁶ HCT116 cells. When tumors reached 100-120 mm³, mice received OSI-906 (25 mg/kg/day, oral gavage) for 28 days. Drug dissolved in 0.5% methylcellulose + 0.2% Tween 80; tumor volume measured every 3 days [1]
- H460 orthotopic lung model (nude mice): 1×10⁶ H460 cells were injected into left lung lobe. Seven days later, mice received OSI-906 (30 mg/kg/day, oral gavage) for 35 days. 18FDG-PET imaging was performed every 7 days to assess tumor metabolism [2]
- A549 xenograft model (nude mice): Mice were implanted with 2×10⁶ A549 cells subcutaneously. When tumors reached 150 mm³, mice received OSI-906 (20 mg/kg/day, oral gavage) for 21 days [1]

In mice: Oral bioavailability of OSI-906 = 52% (25 mg/kg); plasma half-life (t1/2) = 4.8 h; peak plasma concentration (Cmax) 1.2 h after oral administration = 4.1 μM [1] - In rats: Intravenous clearance (10 mg/kg) = 13 mL/min/kg; steady-state volume of distribution (Vss) = 0.9 L/kg [1] - In dogs: Oral bioavailability = 48% (15 mg/kg); half-life (t1/2) = 6.5 h [1] - Plasma protein binding: 99.2% (human plasma, ultrafiltration) [1]

In the 28-day HCT116 study (25 mg/kg/day, orally): no weight loss (>8%); serum ALT = 29 ± 5 U/L, BUN = 18 ± 3 mg/dL (normal range) [1]
- In the 35-day H460 study (30 mg/kg/day, orally): 1 out of 8 mice experienced mild diarrhea (resolved on day 10); no histopathological changes were observed in the liver and kidneys [2]

[1]. Discovery of OSI-906: a selective and orally efficacious dual inhibitor of the IGF-1 receptor and IR. Future Med Chem. 2009 Sep;1(6):1153-71.

[2]. 18FDG-PET predicts pharmacodynamic response to OSI-906, a dual IGF-1R/IR inhibitor, in preclinical mouse models of lung cancer. Clin Cancer Res. 2011 May 15;17(10):3332-40.

[3]. Effectiveness of inhibitor rapamycin, saracatinib, linsitinib and JNJ-38877605 against human prostate cancer cells. Int J Clin Exp Med. 2015 Apr 15;8(4):6563-7.

3-[8-amino-1-(2-phenyl-7-quinolinyl)-3-imidazo[1,5-a]pyrazinyl]-1-methyl-1-cyclobutanol belongs to the quinoline and cyclobutane classes of compounds. OSI-906 is a small molecule insulin-like growth factor 1 receptor (IGF-1R) inhibitor with high oral bioavailability and potential antitumor activity. The IGF-1R inhibitor OSI-906 selectively inhibits IGF-1R, thereby inhibiting tumor cell proliferation and inducing tumor cell apoptosis. Linsitinib is a small molecule insulin-like growth factor 1 receptor (IGF-1R) inhibitor with high oral bioavailability and potential antitumor activity. Linsitinib selectively inhibits IGF-1R, thereby inhibiting tumor cell proliferation and inducing tumor cell apoptosis. IGF-1R is overexpressed in various human cancers; it can stimulate cell proliferation, promote carcinogenesis, and inhibit apoptosis. Drug Indications Investigating for the treatment of cancer/tumors (unspecified) and solid tumors. Mechanism of Action IGF-1R stimulates cell proliferation, promotes carcinogenesis, and inhibits apoptosis. Because overexpression of IGF-1R and/or its ligands, or downregulation of ligand-binding proteins, occurs in a variety of human malignancies, including lung cancer, colon cancer, breast cancer, prostate cancer, brain cancer, and skin cancer, IGF-1R inhibitors hold promise for broad applications in oncology. Furthermore, the IGF signaling pathway has been shown to protect tumor cells from apoptosis induced by anticancer therapies (e.g., cytotoxic drugs and EGFR inhibitors). Pharmacodynamics In laboratory studies of 28 human tumor cell lines, OSI-906 inhibited the growth of 15 cell lines representing colorectal cancer, lung cancer, breast cancer, pancreatic cancer, and pediatric tumors, as well as mouse models. OSI-906 was particularly effective against tumors highly dependent on IGF, such as colorectal cancer. Researchers say that OSI-906 can not only slow the growth of tumors in mice, but also shrink some existing tumors. OSI-906 (lincitinib) is an ATP-competitive dual IGF-1R/IR inhibitor designed to target cancers that depend on the IGF-1R/IR signaling pathway (colorectal cancer, lung cancer, prostate cancer)[1] - 18FDG-PET imaging can predict the response of lung cancer patients to OSI-906 and is associated with tumor growth inhibition[2] - In prostate cancer cells, OSI-906 is more potent than rapamycin (in PC-3 cells, the IC50 of OSI-906 is 22 nM, while that of rapamycin is 150 nM)[3]

C26H23N5O

421.49

421.19

C, 74.09; H, 5.50; N, 16.62; O, 3.80

867160-71-2

11640390

White to yellow solid powder

1.4±0.1 g/cm3

1.748

3.23

2

5

3

32

663

0

NC1=NC=CN2C([C@@H]3C[C@@](O)(C)C3)=NC(=C12)C1C=CC2C=CC(C3C=CC=CC=3)=NC=2C=1

PKCDDUHJAFVJJB-UHFFFAOYSA-N

InChI=1S/C26H23N5O/c1-26(32)14-19(15-26)25-30-22(23-24(27)28-11-12-31(23)25)18-8-7-17-9-10-20(29-21(17)13-18)16-5-3-2-4-6-16/h2-13,19,32H,14-15H2,1H3,(H2,27,28)

3-[8-amino-1-(2-phenylquinolin-7-yl)imidazo[1,5-a]pyrazin-3-yl]-1-methylcyclobutan-1-ol

OSI906; Linsitinib; OSI-906; OSI 906

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)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.93 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 (5.93 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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Solubility in Formulation 3: 30% PEG 400+0.5% Tween 80+5% Propylene glycol: 30 mg/mL

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Solubility in Formulation 4: 5 mg/mL (11.86 mM) in 30% Solutol HS-15 (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.

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