A45 INFLIXIMAB IN COMBINATION WITH AN IMMUNOMODULATOR IS ASSOCIATED WITH AN ATTENUATED ANTIBODY RESPONSE TO BNT162B2 SARS-COV-2 VACCINE IN PEDIATRIC INFLAMMATORY BOWEL DISEASE PATIENTS

Background

Adult data have shown that Infliximab (IFX) impairs the antibody response to a single dose of the mRNA-BNT162b2 SARS-CoV-2 vaccine in patients with inflammatory bowel disease (IBD). The true impact of IFX on SARS-CoV-2 vaccine efficacy in pediatric IBD (PIBD) patients is unknown.

Aims

To evaluate the humoral immune response to the BNT162b2 SARS-CoV-2 in PIBD patients treated with anti-tumor necrosis factor (TNF) therapy.

Methods

PIBD patients treated with anti-TNF therapy either alone or in combination with an immunomodulator, who received at least one dose of the BNT162b2 SARS-CoV-2 vaccine, were prospectively enrolled from 1st June 2021 at BC Children’s Hospital. Serum antibody levels for [spike (S) protein and receptor-binding domain (RBD)] were determined at baseline and 28 days after their first and second vaccine doses. Antibody responses were assessed using multiplex serology IgG assay against four SARS-CoV-2 antigens: S-protein, RBD, N-terminal domain (NTD) and N-protein using the SARS-CoV-2 Panel 2 (Meso Scale Diagnostics).

Results

Forty-two PIBD patients received a single dose of BNT162b2 (median age 14.5yrs (IQR 14–16); 43% female; 79% crohn’s disease, 21%, ulcerative colitis). Of those on IFX monotherapy (43%), both S-protein and RBD antibody concentrations 28 days post BNT162b2 were comparable to healthy adult controls (n=20, median age: 36yrs (IQR 29–40); 65% female) who had received one dose of BNT162b2 (p = 0.07) [Figure 1]. In PIBD patients on IFX in combination with either azathioprine or methotrexate (57%) both S-protein and RBD antibody concentrations were significantly lower than controls after 1 dose of BNT162b2 (p = 0.0003) [Figure 1].

In the PIBD cohort (n=27) who received 2 doses of BNT162b2 vaccine (median age 14yrs (IQR 14–16);41% female;63% crohn’s disease, 37% ulcerative colitis; median interval between doses 56 days (IQR 22–105)), there was no difference in antibody response after 2 doses compared to healthy adult controls (n=14, median age: 44 years (IQR 36–51); 29% female) whether they were on IFX monotherapy (41%) or in combination with an immunomodulator (59%) [Figure 1].

Conclusions

We provide evidence of an attenuated antibody response in PIBD patients on IFX in combination with an immunomodulator after a single dose of BNT162b2. However, our data show a robust antibody response in PIBD patients, despite their infliximab treatment, after two doses of BNT162b2 vaccine. Our results are consistent with adult IBD data and highlight the importance of administering the second vaccine dose to achieve protection in this vulnerable patient population. Long-term follow-up to assess longevity of vaccine protection is warranted.

Funding Agencies

None

Abstract 1426: Multiomic analysis identifies CPT1A and fatty acid oxidation as a potential therapeutic target in platinum-refractory high grade serous ovarian cancer

Platinum-based DNA cross-linking agents are widely used anti-cancer drugs. Tumor resistance to platinum compounds is a major determinant of patient survival, including in high grade serous ovarian cancer (HGSOC). Remarkably, despite >30 years of literature on platinum responses in human cancer, none of these findings is used clinically as a predictive biomarker to stratify patients for platinum resistance, nor exploited therapeutically to treat platinum-resistant disease. Thus, understanding mechanisms of platinum resistance is an urgent goal, both to identify predictive biomarkers of platinum response (to spare patients with platinum-resistant tumors futile platinum therapy) and to develop efficacious therapies for platinum-resistant disease. To better understand mechanisms underlying platinum resistance in HGSOC, we performed comprehensive, dynamic (+/-carboplatin), multiomic profiling of DNA, RNA, protein and post-translational modifications (phosphorylation, ubiquitination, acetylation) to identify the cellular networks that respond to platinum treatment and associate with platinum resistance in three HGSOC intra-patient cell line pairs (PEA1S/PEA2R, PEO1S/PEO4R, PEO14S/PEO23R). The cell line pairs were derived from ascites or pleural effusions (Langdon et al., 1988) from three patients both before (PEA1S, PEO1S, PEO14S) and after (PEA2R, PEO4R, PEO23R, respectively) their tumors became clinically platinum resistant (i.e., in vivo development of resistance). The molecular profiles revealed extensive responses to carboplatin and differential responses between platinum-sensitive and platinum-resistant cells. Higher oxidative phosphorylation and fatty acid oxidation (FAO) pathway expression were observed in the platinum-resistant cells, which was further validated in patient-derived xenograft (PDX) models. We show that pharmacologic inhibition or CRISPR knockout of CPT1A, which represents a rate limiting step of FAO, sensitize HGSOC cells to platinum. Thus, FAO, and CPT1A in particular, represent a candidate therapeutic target to overcome platinum resistance in HGSOC.

Citation Format: Hong Wang, Dongqing Hugang, Shrabanti Chowdhury, Sara Savage, Richard Ivey, Jacob Kennedy, Jeffrey Whiteaker, Chenwei Lin, Xiaonan Hou, Catherine Huntoon, Uliana Voytovich, Zahra Shire, Qing Yu, Steven Gygi, Andrew Hoofnagle, Zachary Herbert, Anna Calinawan, Larry Karnitz, S. John Weroha, Scott Kaufmann, Bing Zhang, Pei Wang, Michael Birrer, Amanda Paulovich. Multiomic analysis identifies CPT1A and fatty acid oxidation as a potential therapeutic target in platinum-refractory high grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1426.

Abstract PR02: Proteogenomic approach to identify mechanisms of platinum refractoriness in high-grade serous ovarian cancers

Although high-grade serous ovarian cancers (HGSOC) are highly chemosensitive with an 85% initial response rate to platinum-based chemotherapy, 15% of patients are “exceptional nonresponders,” with platinum-refractory tumors that remain stable or progress during treatment. Unfortunately, we have no predictive biomarkers to identify refractory patients up front, and they receive futile chemotherapy through which most patients become too ill to be eligible for clinical trials. Hence, no progress has been made in treating these deadly tumors. The goal of this study is to identify mechanisms of platinum refractoriness to: i) predict refractory HGSOCs up front and ii) identify potential new drug targets in refractory disease to point to desperately needed new therapeutic approaches. Of note, 80-90% of patients who are initially platinum responsive will relapse and develop platinum-resistant disease, and it is possible that findings in platinum-refractory tumors might also provide insights into platinum-resistant tumors. Our NCI Clinical Proteomic Tumor Analysis Consortium (CPTAC)-funded approach combines genomic and proteomic (“proteogenomic”) analyses of both preclinical models (0, 8, and 24 hours post-platinum exposure) and treatment-naïve human tumors. For preclinical models, we studied a well-characterized collection of patient-derived xenograft (PDX) models (10 sensitive, 10 refractory), as well as intrapatient HGSOC cell line pairs derived from patients before and after the development of platinum resistance. For the PDX models, proteogenomic profiling included RNASeq, WES, global proteomics, and phosphoproteomics at all 3 time points (0, 8, 24 hours). For cell line models (3 sensitive, 3 resistant), proteogenomic profiling was performed at all 3 timepoints (0, 8, 24 hours), and experiments were performed in complete biologic triplicate. Analyses included RNASeq, WES, global proteomics, phosphoproteomics, ubiquitin proteome, acetylated proteome, and pTyr. A large collection of 275 human HGSOCs (an approximate equal balance of platinum sensitive and refractory tumors) is currently undergoing proteomic profiling, and genomic profiles (WGS, RNASeq) will be performed on a subset. In parallel, we have performed a comprehensive review of 31 years of published work on platinum responses of human cancers, identifying ~700 genes implicated in the response and scoring each gene with respect to strength of the published evidence. Using a Bayesian approach, we are integrating the curated candidates from the literature with our empirical proteogenomic datasets to identify a candidate signature for detecting platinum-refractory disease prior to chemotherapy. We are also performing gene-regulatory network analysis to identify potential drivers of chemo response. NextGen, targeted, multiplex, multiple reaction monitoring mass spectrometry-based assays are being developed to quantify proteins in the signature for validation studies, using independent patient cohorts.

This abstract is also being presented as Poster A62.

Citation Format: Jacob J. Kennedy, Shrabanti Chowdhury, Sara R. Savage, Xiaonan Hou, Catherine J. Huntoon, Richard G. Ivey, Qing Yu, Chenwei Lin, Dongqing Huang, Lei Zhao, Uliana J. Voytovich, Regine M. Schoenherr, Zahra Shire, Steven J. Skates, Jeffrey R. Whiteaker, Andrew N. Hoofnagle, Samuel C. Mok, Bing Zhang, Larry M. Karnitz, S. John Weroha, Steven P. Gygi, Scott H. Kaufmann, Pei Wang, Michael J. Birrer, Amanda G. Paulovich. Proteogenomic approach to identify mechanisms of platinum refractoriness in high-grade serous ovarian cancers [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr PR02.

Nanoencapsulation of Novel Inhibitors of PNKP for Selective Sensitization to Ionizing Radiation and Irinotecan and Induction of Synthetic Lethality

There is increasing interest in developing and applying DNA repair inhibitors in cancer treatment to augment the efficacy of radiation and conventional genotoxic chemotherapy. However, targeting the inhibitor is required to avoid reducing the repair capacity of normal tissue. The aim of this study was to develop nanodelivery systems for the encapsulation of novel imidopiperidine-based inhibitors of the DNA 3'-phosphatase activity of polynucleotide kinase/phosphatase (PNKP), a DNA repair enzyme that plays a critical role in rejoining DNA single- and double-strand breaks. For this purpose, newly identified hit compounds with potent PNKP inhibitory activity, imidopiperidines A12B4C50 and A83B4C63 were encapsulated in polymeric micelles of different poly(ethylene oxide)- b-poly(ε-caprolactone) (PEO- b-PCL)-based structures. Our results showed efficient loading of A12B4C50 and A83B4C63 in PEO- b-PCLs with pendent carboxyl and benzyl carboxylate groups, respectively, and relatively slow release over 24 h. Both free and encapsulated inhibitors were able to sensitize HCT116 cells to radiation and the topoisomerase I poison, irinotecan. In addition, the encapsulated inhibitors were capable of inducing synthetic lethalilty in phosphatase and tensin homologue (PTEN)-deficient cells. We also established the validity of the peptide GE11 as a suitable ligand for active targeted delivery of nanoencapsulated drugs to colorectal cancer cells overexpressing epidermal growth factor receptor (EGFR). Our results show the potential of nanoencapsulated inhibitors of PNKP as either mono or combined therapeutic agents for colorectal cancer.