PD-1/ PD-L1

PD-1-IN-17, an analogue of CA-170, is a programmed cell death-1 (PD-1) inhibitor.

[1]. 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives as immunomodulators. WO2015033301A1.

CA-170 is a selective small molecule PD-L1 inhibitor. The PD-L1/PD-L2/VISTA antagonist CA-170 is an orally bioavailable small molecule inhibitor that inhibits the immune checkpoint regulatory proteins programmed death-ligand-1 (PD-L1; B7-H1; CD274), PD-L2, and V-domain immunoglobulin (Ig) T-cell activation inhibitor (VISTA; programmed death-1 homolog; PD1H; PD-1H), exhibiting potential negative immune checkpoint modulation and antitumor activity. After oral administration, the PD-L1/PD-L2/VISTA antagonist CA-170 targets and binds to PD-L1, PD-L2, and VISTA. This drug inhibits the PD-L1/PD-L2/VISTA-mediated signaling pathway, eliminates the suppression of T lymphocyte immune responses induced by PD-L1, PD-L2, and VISTA, enhances the proliferation and activation of cytotoxic T cells, promotes T cell cytokine production, and inhibits tumor cell growth. PD-L1, PD-L2, and VISTA are negative checkpoint molecules of immune activation, playing a crucial role in suppressing T cell function. CA-170 is currently the only small molecule modulator undergoing clinical trials, targeting PD-L1 and VISTA proteins—important regulators of negative checkpoints of immune activation. Reported treatment results are somewhat similar to those of FDA-approved monoclonal antibodies, overcoming the limitations of the latter's high production costs and significant side effects. However, there is currently no conclusive biophysical evidence demonstrating that CA-170 binds to hPD-L1. Using established in vitro methods, including NMR binding assays, HTRF assays, and cell activation assays, we have clearly demonstrated that there is no direct binding between CA-170 and PD-L1. To further validate our findings, we conducted control experiments on the CA-170 precursor, the 29-peptide AUNP-12. Positive controls included well-reported small molecule PD-L1 inhibitors: BMS-1166 and peptide-57. [Molecules. 2019 Aug 1;24(15):2804.]

---

CA-170 is the first small molecule inhibitor targeting PD-L1 to enter Phase I and Phase II clinical trials. However, we definitively determined that there is no actual direct binding between CA-170 and its peptide precursor AUNP-12 and PD-L1. In NMR binding assays, neither CA-170 nor AUNP-12 interacted with human or mouse single-domain or double-domain PD-L1, nor with human PD-1. In in vitro systems of HTRF assays and cell assays simulating in vivo conditions, CA-170 and AUNP-12 also failed to dissociate the complex. All measurements were cross-validated using the positive control peptide-57 and the small molecule BMS-1166. Therefore, the mechanism by which CA-170 directly blocks the hPD-1/hPD-L1 interaction needs to be revised. [Molecules. Aug 1, 2019;24(15):2804.]

C13H22N6O7

374.3498

374.154

C, 41.71; H, 5.92; N, 22.45; O, 29.92

1673560-66-1

PD-1-IN-17 TFA

131998882

White to off-white solid powder

-6.7

7

10

10

26

507

4

O1C(C([H])(C([H])(C([H])([H])[H])O[H])N([H])[H])=NN=C1C([H])(C([H])([H])C([H])([H])C(N([H])[H])=O)N([H])C(N([H])C([H])(C(=O)O[H])C([H])([H])O[H])=O

SRNQPYBWRIETFQ-XKBZYTNZSA-N

InChI=1S/C13H22N6O7/c1-5(21)9(15)11-19-18-10(26-11)6(2-3-8(14)22)16-13(25)17-7(4-20)12(23)24/h5-7,9,20-21H,2-4,15H2,1H3,(H2,14,22)(H,23,24)(H2,16,17,25)/t5-,6+,7+,9+/m1/s1

(2S)-2-[[(1S)-4-amino-1-[5-[(1S,2R)-1-amino-2-hydroxypropyl]-1,3,4-oxadiazol-2-yl]-4-oxobutyl]carbamoylamino]-3-hydroxypropanoic acid

PD-1-IN-17; PD-1-IN-17 free base; PD1-IN-1; (2S)-2-[[(1S)-4-amino-1-[5-[(1S,2R)-1-amino-2-hydroxypropyl]-1,3,4-oxadiazol-2-yl]-4-oxobutyl]carbamoylamino]-3-hydroxypropanoic acid; (S)-2-(3-((S)-4-Amino-1-(5-((1S,2R)-1-amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-4-oxobutyl)ureido)-3-hydroxypropanoic acid; CHEMBL4458504; SCHEMBL19450456;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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

DMSO : ~125 mg/mL (~333.91 mM)
H2O : ≥ 100 mg/mL (~267.13 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.56 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 20.8 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.

---

Solubility in Formulation 2: ≥ 2.08 mg/mL (5.56 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 20.8 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.

---

View More

Solubility in Formulation 3: ≥ 2.08 mg/mL (5.56 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

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