Preclinical activity in non-Hodgkin’s lymphoma of selinexor, a Selective Inhibitor of Nuclear Export (SINE), is enhanced through combination with standard-of-care therapies Asfar S. Azmi1, Amro Aboukameel1, Robert O. Carlson2, Sivan Elloul2, Sharon Shacham2, Michael Kauffman2, Ran Frenkel3, Ramzi M. Mohammad1 1Wayne State University, Detroit, MI; 2Karyopharm Therapeutics, Newton, MA; 3Karyopharm Europe GmbH, Munich, Germany ABSTRACT RESULTS RESULTS DLBCL cell line Selinexor IC50 (µM) RL 0.020 0.050 0.057 0.063 0.070 0.096 0.120 0.150 0.29 0.44 0.48 Control SEL EVER SEL+EVER DLBCL cell lines were incubated with a range of selinexor concentra8ons over 72 hr. Resul8ng cell viability was determined using an MTT-‐based assay. (*Double hit) 1200 B Vehicle CHOP KPT-276 (75 mg/kg) 1000 KPT-276 (150 mg/kg) KPT 251 (25 mg/kg) KPT 251 (75 mg/kg) 800 avg. tumor vol. day 1: 125 ± 58 mm3 P<0.05 vs vehicle (Mann Whitney): CHOP Day 10 and 12; KPT-276 (150 mpk) Day 12 600 400 200 0 2 4 6 8 10 12 15 C Vehicle vehicle rituximab 20 mg/kg IV selinexor 20 mg/kg PO selinexor 30 mg/kg PO CHOP KPT-276 (75 mg/kg) KPT-276 (150 mg/kg) 10 KPT 251 (25 mg/kg) 75 KPT 251 (75 mg/kg) 5 0 ** 50 **** ** 25 avg. mouse et Day 1: 20.2 ± 1.5 g -5 **p<0.01; ****p<0.0001 vs vehicle (Greenwood) P<0.05 vs vehicle (Mann Whitney): all treatments, all time points Day 3-12, except KPT-276 (75 mpk) on Days 3 and 12 -10 Time (days) 0 2 4 6 8 10 12 0 Time (days) 0 10 20 30 40 50 60 70 80 90 Time (days post cell inoculation) Equivalent in vivo efficacy of single agent selinexor vs rituximab or CHOP. [A] and [B] Xenograft model of DLBCL. SINE Compounds KPT-251 and KPT-276 were administered sc and po, respectively, in cycles of once daily for ten consecutive days with a one day break prior to start of a new cycle. Cyclophosphamide, doxorubicin and vincristine (CHO) was administered once IV at MTD and prednisone (P) was administered po QDX5. [C] 10X106 WSU-FSCCL follicular lymphoma cells were injected IV in the tail veins of ICR-SCID mice and vehicle or drug treatments were started one week later. C vs Dex = 0.451209899 C vs Kpt = 0.383789488 C vs Combo = 0.025863099 this is for day 25 using ttest on excel, tail=2, type=2 Selinexor synergizes with either DEX or EVER. WSU-FSCCL or WSU-DLCL2 cells were incubated with 100 nM selinexor (SEL) or 100 nM dexamethasone (DEX) or 1.25 μM everolimus (EVER), each drug alone, SEL+DEX or SEL+EVER. [Left Panel] Resulting cell viability was determined using trypan blue staining and cell counting. [Right Panel] Annexin V FITC apoptosis analysis (Sel 100 nM; DEX 100 nM and EV 2.5 μM). SEL (100 nM) - + - + - + - + SEL (100 nM) - + - + - + - + EVER (2.5 µM) - - + + - - + + DEX (100 nM) - - + + - - + + WSU-DLCL2 PARP PARP Caspase 3 Caspase 3 XPO1 XPO1 β-actin β-actin WSU-DLCL2 WSU-FSCCL WSU-FSCCL SEL+Dexamethasone SEL+Everolimus 2000 Control SEL PO 10 mg/kg Ever PO 2.5 mg/kg SEL+Ever (10+2.5) 1500 1000 500 0 750 500 250 0 7 18 21 25 28 32 Days Post WSU-DLCL2 Bilateral Trasplantation Control SEL PO (10 mg/kg) DEX IP (7.5 mg/kg) SEL+DEX (10+7.5) 1000 7 18 21 25 WSU-DLCL2 days post transplantation Selinexor at sub-optimal doses enhances the activity of DEX or EVER in subcutaneous DLBCL xenografts. WSU-DLCL2 xenograft were established as described above. Drugs were administered at indicated doses 5 days a week for three weeks. [Left panel] SEL +EVER and [Right Panel] SEL+DEX combination (study continuing beyond 25 days). CONCLUSIONS KPT-‐251 KPT-‐276 DB 0.55 A 100 Percent survival SEL+DEX median mouse wt (% change from day 1) DEX 0 selinexor OCILY A3/ OCILY SUDH SUDH DOHH WSUD SUDH TOLE PFEIF 3 KAW 19 L5 L8 2* LCL2 L6 DO FER SEL Tumor Weight (mg) Methods: Diffuse large B cell lymphoma (WSU-DLCL2) and follicular small cleaved cell lymphoma cell lines have been previously developed at Wayne State University. All lines are GCB type with the exception of OCI-LY3 (ABC), WSU-DLCL2 (neither) and A3/KAW (unknown). Cell growth inhibition was performed using trypan blue viability assay and MTT assay (CellTiter 96® from Promega) and IC50 values were calculated using GraphPad Prism® software. Apoptosis was detected using Annexin V FITC assay. Changes in protein expression was evaluated using western blotting. For xenograft model of DLBCL, pieces (~50 mg) of serially passaged WSU-DLCL2 tumors were transplanted into the flanks of 4-5 wk old ICR-SCID mice and vehicle or drug treatments were started one week later. 10X106 WSU-FSCCL follicular lymphoma cells were injected IV in the tail veins of ICR-SCID mice and vehicle or drug treatments were started one week later. Control Tumor Weight (mg) METHODS WSU-FSCCL disseminated follicular lymphoma model WSU-DLCL2 DLBCL xenograft model median tumor volume (% of day 1) Introduction: The nuclear export protein Exportin 1 (XPO1) is overexpressed in diffuse large B-cell lymphoma (DLBCL), follicular small cell cleaved lymphoma (FSCCL) and a wide variety of other cancers, which often correlates with poor prognosis. Selinexor is an oral SINE currently in Phase 1/2 clinical testing, which targets XPO1 to induce apoptosis across a broad spectrum of tumor types. This broad action is primarily due to forced nuclear retention and reactivation of tumor suppressor proteins (TSPs), resulting in selective tumor cell death. Here we report combination studies involving selinexor/dexamethasone and selinexor/mTOR inhibitor everolimus in Non Hodgkin’s lymphoma relative to front-line standard-of-care therapies. RESULTS Molecular analysis of SEL-DEX and SEL-EVER synergy. WSU-DLCL2 or WSU-FSCCL were exposed to indicated concentrations of drugs for 72 hrs followed by protein isolation and western blotting. [Upper panel] Results showing enhanced PARP cleavage, full length caspase 3 reduction and decrease in XPO1 expression for combination treatments compared to single agents. β-actin was used as loading control. [Lower panel] Structures of SINEs. • The enhanced in vitro and in vivo efficacy of selinexor in combination with DEX or the mTOR inhibitor everolimus provides rationale for further clinical investigation. • The equivalent efficacy of single agent selinexor vs rituximab or CHOP is consistent with observed clinical activity of selinexor in refractory DLBCL and follicular lymphoma. • A Phase 2 study of selinexor in DLBCL is currently recruiting patients. (Study of Selinexor (KPT-330) in Patients With Relapsed/Refractory Diffuse Large B-Cell Lymphoma” (SADAL – NCT02227251).
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