Abstract LB-074: Regression of duodenal neoplasia in familial adenomatous polyposis patients using COX and EGFR inhibition: A randomized placebo-controlled trial

The objective of this trial was to test the effect of a combination of COX and EGFR inhibition on duodenal adenoma progression in patients with familial adenomatous polyposis (FAP). FAP is caused by mutations in the APC gene and is characterized by the development of hundreds of colorectal adenomas and colorectal cancer. FAP patients are also at increased risk for duodenal neoplasia with a ∼10% lifetime risk of duodenal carcinoma. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful. Preclinical data has illustrated that a combination of cyclooxygenase (COX) and epidermal growth factor (EGFR) inhibition diminishes small intestinal adenoma development by 87% in mice with germline Apc mutations. Therefore, we conducted a double blind, randomized, placebo-controlled trial in which FAP patients received combination therapy with 150 mg sulindac twice per day and 75 mg erlotinib daily or placebo for 6 months (NCT01187901). The total number and diameter of polyps in a 10cm segment of the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden, calculated as the sum of the diameters of polyps. We also evaluated RNA expression in duodenal tissue and polyps at endpoint from 10 patients on drug and 10 patients on placebo by RNA sequencing. Seventy-three randomized patients were included in the intention to treat analysis. Over six months, the median change in total duodenal polyp burden was an increase of 8.0 mm from baseline burden in the placebo group (23.0 to 31.0 mm) and the median change in the sulindac-erlotinib group was a decrease of 8.5 mm (29.0 to 19.5 mm). The estimated net difference in change between the two groups was -19.0 mm (95% CI: -32.0, -10.9; P<0.001). Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of patients receiving treatment and 20% of patients receiving placebo (P<0.001). We identified ∼ 750 differentially expressed genes (fold ≥ 2, false discovery rate < 0.05) in polyps from patients on placebo as compared with patient-matched normal duodenum which were unchanged in polyps from patients on drug. These differentially expressed genes suggested increased EGFR, prostaglandin E2 (PGE2 or COX2) and WNT signaling in duodenal polyps from patients on placebo but not on drug. In duodenal tissue from patients on drug when compared to tissue from patients on placebo, we identified differentially expressed genes suggestive of a reactivated immune response including interferon gamma and interleukin 12 signaling; a possible mechanism for the regression of duodenal polyps observed in drug treated patients. In conclusion, combined chemoprevention with sulindac and erlotinib in FAP patients is effective to lower duodenal polyp burden, block COX2 and EGFR activity, and may reactivate immune surveillance. At the doses tested, however, frequent adverse events may limit the use of these medications.

Part of this abstract was presented as part of a preliminary presentation.

Citation Format: Deborah W. Neklason, Don A. Delker, Kenneth M. Boucher, Priyanka Kanth, Kathryn Byrne, Philip Bernard, Wade Samowitz, Michelle W. Done, Therese Berry, Lisa Pappas, Laurel Smith, Danielle Sample, Rian Davis, Matthew K. Topham, Randall W. Burt, Scott K. Kuwada, N Jewel Samadder. Regression of duodenal neoplasia in familial adenomatous polyposis patients using COX and EGFR inhibition: A randomized placebo-controlled trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-074.

Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis: A Randomized Clinical Trial

IMPORTANCE

Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal polyps and cancer. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful.

OBJECTIVE

To evaluate the effect of a combination of sulindac and erlotinib on duodenal adenoma regression in patients with FAP.

DESIGN, SETTING, AND PARTICIPANTS

Double-blind, randomized, placebo-controlled trial, enrolling 92 participants with FAP, conducted from July 2010 through June 2014 at Huntsman Cancer Institute in Salt Lake City, Utah.

INTERVENTIONS

Participants with FAP were randomized to sulindac (150 mg) twice daily and erlotinib (75 mg) daily (n = 46) vs placebo (n = 46) for 6 months.

MAIN OUTCOMES AND MEASURES

The total number and diameter of polyps in the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden at 6 months. Polyp burden was calculated as the sum of the diameters of polyps. The secondary outcomes were change in total duodenal polyp count, change in duodenal polyp burden or count stratified by genotype and initial polyp burden, and percentage of change from baseline in duodenal polyp burden.

RESULTS

Ninety-two participants (mean age, 41 years [range, 24-55]; women, 56 [61%]) were randomized when the trial was stopped by the external data and safety monitoring board because the second preplanned interim analysis met the prespecified stopping rule for superiority. Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of participants receiving treatment and 20% of participants receiving placebo (P < .001). Only 2 participants experienced grade 3 adverse events. [table: see text].

CONCLUSIONS AND RELEVANCE

Among participants with FAP, the use of sulindac and erlotinib compared with placebo resulted in a lower duodenal polyp burden after 6 months. Adverse events may limit the use of these medications at the doses used in this study. Further research is necessary to evaluate these preliminary findings in a larger study population with longer follow-up to determine whether the observed effects will result in improved clinical outcomes.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT 01187901.

Activating mutation in MET oncogene in familial colorectal cancer

Background

In developed countries, the lifetime risk of developing colorectal cancer (CRC) is 5%, and it is the second leading cause of death from cancer. The presence of family history is a well established risk factor with 25-35% of CRCs attributable to inherited and/or familial factors. The highly penetrant inherited colon cancer syndromes account for approximately 5%, leaving greater than 20% without clear genetic definition. Familial colorectal cancer has been linked to chromosome 7q31 by multiple affected relative pair studies. The MET proto-oncogene which resides in this chromosomal region is considered a candidate for genetic susceptibility.

Methods

MET exons were amplified by PCR from germline DNA of 148 affected sibling pairs with colorectal cancer. Amplicons with altered sequence were detected with high-resolution melt-curve analysis using a LightScanner (Idaho Technologies). Samples demonstrating alternative melt curves were sequenced. A TaqMan assay for the specific c.2975C >T change was used to confirm this mutation in a cohort of 299 colorectal cancer cases and to look for allelic amplification in tumors.

Results

Here we report a germline non-synonymous change in the MET proto-oncogene at amino acid position T992I (also reported as MET p.T1010I) in 5.2% of a cohort of sibling pairs affected with CRC. This genetic variant was then confirmed in a second cohort of individuals diagnosed with CRC and having a first degree relative with CRC at prevalence of 4.1%. This mutation has been reported in cancer cells of multiple origins, including 2.5% of colon cancers, and in <1% in the general population. The threonine at amino acid position 992 lies in the tyrosine kinase domain of MET and a change to isoleucine at this position has been shown to promote metastatic behavior in cell-based models. The average age of CRC diagnosis in patients in this study is 63 years in mutation carriers, which is 8 years earlier than the general population average for CRC.

Conclusions

Although the MET p.T992I genetic mutation is commonly found in somatic colorectal cancer tissues, this is the first report also implicating this MET genetic mutation as a germline inherited risk factor for familial colorectal cancer. Future studies on the cancer risks associated with this mutation and the prevalence in different at-risk populations will be an important extension of this work to define the clinical significance.