Kramer, Zachary

Objectives:Patients with Trisomy 21 (T21) commonly have gastrointestinal symptoms and diseases that prompt evaluation with esophagogastroduodenoscopy (EGD). Our objective is to characterize duodenal histological abnormalities in these patients when undergoing EGD. A secondary aim is to explore associations of histologic findings with different therapies.Methods:Patients 30 years old or younger with T21 who underwent EGD from 2000 to 2020 at 6 hospitals were included in this retrospective cohort study. Duodenal biopsies were categorized based on reported histopathology findings as normal or abnormal. Abnormal pathology reports were reviewed and categorized into villous atrophy (VA) and duodenitis without VA. The VA group was further categorized based on the presence or absence of celiac disease (CD).Results:We identified 836 patients with T21 who underwent EGD, 419 (50.1%) of whom had duodenal histologic abnormalities. At the time of the first (index) abnormal duodenal biopsy, 290 of 419 had VA and of those, 172 of 290 met CD diagnostic criteria, while 118 of 290 did not meet CD criteria (nonspecific VA). Among the patients with an abnormal biopsy, acid suppression at the time of the index biopsy was less common in patients with VA‐CD compared to patients without VA or patients with nonspecific VA (12.2% vs 45.7% vs 44.9%).Conclusions:Half of the T21 patients in this cohort had abnormal duodenal biopsies including a subgroup with nonspecific VA. In this cohort, acid suppression use was more prevalent in patients with abnormalities other than CD.

4083 Background: Thymidylate synthase (TS) over-expression is associated with 5-FU resistance. Pre-clinical studies demonstrate that vorinostat down-regulates intra-tumor TS in a dose-dependent fashion and augments 5-FU antitumor activity in xenograft models. We conducted a phase I clinical trial of an intermittent schedule of QD x 3 vorinostat in combination with a fixed dose of fluorouracil (5-FU) and leucovorin (LV) in patients (pts) with refractory solid tumors. Methods: Vorinostat was escalated in a standard 3 x 3 design in combination with a fixed dose of 5-FU and LV (simplified de Gramont regimen, sFULV2). Vorinostat was given QD x 3 on an every-2-week cycle. sFULV2 started on day 2 of vorinostat and consisted of leucovorin 400 mg/m2 i.v. over 2 hrs followed by 5-FU 400 mg/m2 bolus and 5-FU 2400 mg/m2 over 46 hrs. Results: 24 pts were enrolled: Male/Female: 11/13; ECOG 0/1: 6/18; Age: median 60 (range 42–77) yrs. 21 pts had colorectal cancer (CRC), 1 had gastric, 1 had esophageal, and 1 had anal cancer. Vorinostat dose-levels (DL) were 600 mg, 800 mg, 1000 mg, 1200 mg, 1400 mg, 1700 mg, and 2000 mg. Dose-limiting toxicities (DLT), consisting of fatigue and hand-and-foot syndrome (H&F), were seen in 2 of 3 pts at the 2000 mg DL. None of the 6 pts at the 1700 mg DL had a DLT. Cycle 1 grade 3/4 toxicities consisted of thrombocytopenia, GI bleeding, fatigue, and H&F in 2 pts at the 2000 mg DL and a non-DLT G3 diarrhea (lasted <24 hrs) in 1 pt at the 1700 mg DL. Grade 2 nausea, fatigue, and anorexia were common; especially at DL ≥ 1700 mg. Antitumor activity was noted in pts with CRC despite prior refractoriness to 5-FU and failure to oxaliplatin, irinotecan, and cetuximab in all pts. 12/21 CRC pts had a confirmed SD (11) or PR (1). CRC pts had a median PFS of 4 months, a ≥ 6 months PFS rate of 43%, and a ≥ 8 months PFS rate of 33%. Conclusions: The maximum tolerated dose (MTD) of vorinostat in combination with sFULV2 is 1700 mg PO QD x 3 every 2 weeks. This combination is associated with considerable activity in pts with 5-FU-refractory CRC and warrants further investigation. An expanded MTD cohort is accruing to investigate 5-FU-vorinostat PK interaction and intra-tumor TS down-regulation. (This work was supported by a grant from CTEP and the ACS.) No significant financial relationships to disclose.