Trials-In-Progress, A Phase 1-2, Open-Label Study of the Safety, Pharmacokinetics, Pharmacodynamics, and Preliminary Activity of Tolinapant in Combination with Oral Decitabine/Cedazuridine and Oral Decitabine/Cedazuridine Alone in Subjects with Relapsed/Refractory Peripheral T-cell Lymphoma
There are limited treatment options for patients with PTCL after front line therapy has failed. Tolinapant (ASTX660) is a novel oral non-peptidomimetic, small-molecule antagonist of cellular/X-linked inhibitors of apoptosis proteins (cIAP1/2 and XIAP), which also induces necroptosis in T-cell lymphoma models (Ferrari et al., Blood Advances, 2021). An ongoing Phase 1/2 study demonstrates an overall response rate (ORR) of >20% in relapsed/refractory PTCL with single agent tolinapant (Michot et al., EHA 2022). While there are limited studies using hypomethylating agents (HMAs) in PTCL, a recent prospective study showed 40% ORR (Wong et al., Leukemia, 2022). Preclinical data demonstrate decitabine treatment leads to re-expression of gene expression critical for necroptosis and synergy between decitabine and tolinapant in T-cell tumor models (Ward et al. ASH 2021; Manavalan et al; EHA abstract 2022). These data suggest that this combination may have synergistic activity in PTCL. There are minimal overlapping toxicities between the study drugs and no expected drug-drug interactions. Oral decitabine and cedazuridine (an inhibitor that enhances the oral bioavailability of decitabine) is an oral fixed dose combination of the two drugs with pharmacokinetic equivalence to IV decitabine. This combination was recently approved in the US, Canada, and Australia for the treatment of intermediate and high-risk MDS and CMML.
ASTX660-03 is a Phase 1-2, open-label study investigating the safety and efficacy of combination tolinapant and oral decitabine/cedazuridine treatment in relapsed/refractory PTCL. To be eligible, subjects with ECOG PS ≤2 must have received at least two prior systemic therapies with evidence of documented progressive disease with at least one measurable lesion by CT. Subjects with CD30-positive disease must have received, be ineligible for, or intolerant to brentuximab vedotin. Key exclusion criteria include ejection fraction <50%, QTc >470 msec, and the use of concomitant medications that are either strong or moderate CYP3A4 inhibitors/inducers.
There is a lead-in phase to confirm tolerability of the MDS-approved regimen of oral decitabine/cedazuridine is tolerated in a PTCL population. Phase 1 is randomized to oral decitabine/cedazuridine alone or in combination with tolinapant. The combination arm will have escalation of tolinapant in dose ranges that have shown efficacy in PTCL. The oral decitabine/cedazuridine only arm will enroll 20-24 subjects. Once the combination arm reaches recommended Phase 2 dose/maximum tolerated dose there will be a dose expansion of 20 subjects in the combination arm prior to the initiation of the combination dosing in Phase 2, with an enrollment goal of 102 subjects. There will be no formal analysis in Phase 1. In Phase 2, there will be efficacy analysis for every 34 subjects, without a pause in enrollment. Anticipated study opening is May 2022.