A randomized, multi-center, phase 2 study of ivaltinostat (Ival) plus capecitabine (Cape) versus capecitabine alone in the maintenance setting in patients with metastatic pancreatic adenocarcinoma (mPDAC).

Abstract

TPS4206 Background: Front-line chemotherapy for patients (pts) with advanced or mPDAC typically consists of mFOLFIRINOX or gemcitabine/nab-paclitaxel given until disease progression or intolerable toxicity. For pts with durable disease control on front-line treatment, maintenance therapy that can effectively delay disease progression while preserving quality of life with minimal cumulative toxicity is highly desirable. Ivaltinostat (ival) is a pan-histone deacetylase inhibitor that increases histone acetylation, suppresses PDAC cell proliferation, and promotes apoptosis in PDAC cell lines. Preclinical data demonstrated synergy with 5-FU/cape in mouse models. RP2D of the Phase 1b combination study of ival and cape in advanced pancreatic cancer was ival 250mg/m2 IV on days 1 and 8 with cape 1000mg/m2 po days 1-14 of a 21-day cycle. Both ival and cape treatment-related AEs >15% were fatigue, nausea, diarrhea, and decreased appetite. Palmar-plantar erythrodysaesthesia syndrome was also commonly observed; all events were attributed to cape. PK and PD demonstrated dose proportionality. Overall and progression-free survival (PFS) were immature, but 70% of pts who enrolled with measurable disease had stable disease as best response. Several pts remained on study with the longest duration of response about 10 months, as of the data cut off for ASCO GI 2024. Based on this data, a randomized phase 2 study is being conducted comparing the combination of ival and cape versus cape alone in the maintenance setting for pts with mPDAC after first line FOLFIRINOX, mFOLFIRINOX or NALFIRINOX therapy. Methods: Key eligibility criteria for the randomized Phase 2 study include: mPDAC; no evidence of disease progression following at least 16 weeks of front-line FOLFIRINOX or NALIRIFOX at full or modified doses; ECOG PS 0-1; and no known germline BRCA1/2 mutation. A total of 52 pts will be randomized 1:1 to receive cape with or without ival until disease progression, with tumor assessments occurring at 6-week intervals. The primary endpoint is investigator-adjudicated PFS, and the primary analysis will compare PFS distributions in the ival/cape and cape alone arms using a one-sided log rank test with an alpha=0.10. The assumed 6-mo PFS rates are 35% (cape), based on historic data, and 60% (ival/cape), corresponding to an HR of 0.487. Enrollment in the phase 2 study began in January 2024 across multiple sites in the US. Accrual is anticipated to complete 4Q2024. Clinical trial information: NCT05249101 .