LCL161

XIAP (IC50 = 35 nM); cIAP1 (IC50 = 0.40 nM)

LCL161 has a strong affinity for inhibitors of apoptosis proteins (IAPs) and starts the destruction of cIAP1 and cIAP2 to further induce apoptosis by activating caspase. When given alone, LCL161 only weakly inhibits the growth of FLT3-ITD-expressing cells, with an IC50 ranging from 0.5 μM (Ba/F3-FLT3-ITD cells) to 4 μM (MOLM13-luc+ cells). When tested against Ba/F3-D835Y cells, LCL161's potency against the D835Y mutant is found to be significantly higher, with an IC50 of less than 50 nM. LCL161 and PKC412 treatment of MOLM13-luc+ cells significantly increases cell death compared to treatment with either agent alone, with Calcusyn combination indices indicating synergy. For MOLM13-luc+ cells, PKC412 and LCL161 cause apoptosis. In comparison to either agent alone, the combination of PKC412 and LCL161 increases the induction of apoptosis. By working well with PKC412 in combination, LCL161 can prevent stromal-mediated rescue of mutant FLT3-expressing cells. A 100 nM IC50 value for LCL161 prevents the growth of Ba/F3.p210 cells. Imatinib, an ABL inhibitor, and LCL161 work together synergistically to kill cells that express the BCR-ABL gene. Drug-resistant cells that express point mutations in the target proteins have also been shown to be active against LCL161. Ba/F3-derived cell lines that express FLT3-ITD and carry point mutations in the ATP-binding pocket of FLT3 can be mostly or completely eliminated by LCL161 at a concentration of 1000 nM. Additionally, LCL161 exhibits activity against Ba/F3 cells expressing various imatinib- and nilotinib-resistant BCR-ABL point mutations at concentrations ranging from 100 to 1000 nM.[1] Using 96 hours, LCL161 is compared to the 23 cell lines in the Pediatric Preclinical Testing Program (PPTP) in vitro panel. Only three of the 23 PPTP cell lines tested by LCL161 exhibit 50% growth inhibition at a concentration of 10 μM. Two of the three cell lines are T-cell ALL cell lines (COG-LL-317 and CCRF-CEM) and one is an anaplastic large cell lymphoma cell line (Karpas-299), with CCRF-CEM and Karpas-299 exhibiting the lowest relative IC50 values (0.25 and 1.6 μM, respectively). [2] On human immune subsets, LCL161 exhibits immunomodulatory properties. With little impact on CD4 and CD8 T-cell survival or proliferation, LCL161-treated T lymphocytes exhibit significantly increased cytokine secretion upon activation. Naive T cell priming in vitro with synthetic peptides is significantly improved by LCL161 treatment of peripheral blood mononuclear cells. The phenotypic maturation of myeloid dendritic cells in response to LCL161 results in a diminished ability to cross-present a tumor antigen-based vaccine. The observed activation of the canonical and non-canonical NF-κB pathways in response to LCL161 and the subsequent upregulation of anti-apoptotic molecules are thought to be the possible mechanisms by which these effects are mediated. [3]

LCL161 significantly improves PKC412's capacity to prevent the development of Ba/F3-FLT3-ITD-luc+ cells in vivo. LCL161 has also been shown to effectively combat FLT3-ITD- and D835Y-expressing cells when combined with the common chemotherapeutic drugs Ara-c and Doxorubicin. Combining nilotinib and lcl161 can suppress leukemia growth in a way that is additive. Nilotinib (100 mg/kg) in high-moderate doses improves the in vivo effects on the burden of leukemia in mice when combined with LCL161 (100 mg/kg).[1] CL161 is evaluated against the in vivo panels of the Pediatric Preclinical Testing Program (PPTP) (30 or 75 mg/kg [solid tumors] or 100 mg/kg [ALL]) when given orally twice per week. About one-third of solid tumor xenografts (glioblastoma and osteosarcoma) show significant differences in EFS distribution in response to LCL161, but not ALL xenografts. There are no detectable objective tumor responses. LCL161 exhibits only modest single agent activity in vivo against the pediatric preclinical models investigated. [2]

In vitro testing is performed using DIMSCAN.

Mice: Male NCr athymic nude mice (5-7 weeks of age) are used. Each mouse is inoculated s.c. in the dorsal flank with 1×106 Huh-7 cells suspended in 0.1 mL of serum-free medium containing 50% Matrigel. When tumors grow to 200–300 mm3, mice are given LCL161 (50 mg/kg) or SC-2001 (10 mg/kg) or both once daily via oral administration. Vehicle is received by controls. Weekly caliper measurements of tumors are performed, and the volume of each tumor is determined using the following formula: width2×length×0.52. LCL161 is a first-in-class oral Smac mimetic that has been shown to cause the cleavage of caspase 3 and the degradation of cIAP1 in mouse xenograft models.
Rats: LCL161 is given orally once weekly over the course of 21 days, with a starting dose of 10 mg (which is equal to one-tenth of the dose that caused severe toxicity in 10% of rats). Once-weekly and twice-daily LCL161 dosing are equally effective in the MDA-MB-231 triple-negative breast cancer xenograft model. Better tolerated with less weight loss is once per week.

[1]. Potent, Dual cIAP1/XIAP Antagonists Induce Apoptosis in a Melanoma Stem Cell Population.

[2]. Inhibition of Bcl-2 improves effect of LCL161, a SMAC mimetic, in hepatocellular carcinoma cells. Biochem Pharmacol. 2012 Aug 1;84(3):268-77.

[3]. Time-dependent inhibition and induction of human cytochrome P4503A4/5 by an oral IAP antagonist, LCL161, in vitro and in vivo in healthy subjects. J Clin Pharmacol. 2013 Jun;53(6):642-53.

[4]. Phase I dose-escalation study of LCL161, an oral inhibitor of apoptosis proteins inhibitor, in patients with advanced solid tumors. J Clin Oncol. 2014 Oct 1;32(28):3103-10.

C26H33FN4O3S

500.63

500.63

C, 62.38; H, 6.64; F, 3.79; N, 11.19; O, 9.59; S, 6.40

1005342-46-0

Solid powder

C[C@@H](C(=O)N[C@@H]

UFPFGVNKHCLJJO-SSKFGXFMSA-N

InChI=1S/C26H33FN4O3S/c1-16(28-2)24(33)30-22(17-7-4-3-5-8-17)26(34)31-14-6-9-21(31)25-29-20(15-35-25)23(32)18-10-12-19(27)13-11-18/h10-13,15-17,21-22,28H,3-9,14H2,1-2H3,(H,30,33)/t16-,21-,22-/m0/s1

(2S)-N-[(1S)-1-cyclohexyl-2-[(2S)-2-[4-(4-fluorobenzoyl)-1,3-thiazol-2-yl]pyrrolidin-1-yl]-2-oxoethyl]-2-(methylamino)propanamide

LCL161; LCL 161; LCL-161

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)