Clinical Case Summary

Introduction: Pyoderma gangrenosum (PG) is a neutrophilic dermatosis, which can occur as an extraintestinal manifestation in inflammatory bowel disease (IBD), often presenting itself with severe skin ulcerations [1]. Regarding treatment, evidence exists for ustekinumab (UST), a monoclonal antibody targeting interleukin-12/23 [2]. However, management of PG occurrence during UST treatment is not clear.
We report of a 30-year-old woman with Crohn’s disease (CD), who developed severe PG on the right leg refractory to glucocorticoids.
She was receiving subcutaneous (s.c.) UST at 90 mg every 4 weeks for CD maintenance therapy but had a decline in serum trough concentration before PG onset.
Our aim to investigate was whether a trough level guided dose intensification via intravenous re-induction would be effective in PG treatment.
Methods: We searched in PubMed for data regarding PG treatment with UST using the terms “ustekinumab and pyoderma gangrenosum”, “ustekinumab trough levels”, “ustekinumab every 4 weeks” and “ustekinumab intravenous re-induction”.
We administered 130 mg UST intravenously 4 weeks after the last s.c. injection, followed by two more infusions 4 and 8 weeks afterwards. Serum trough levels were measured before each infusion.
Results: Our literature review included evidence for successful PG treatment with UST in 9 IBD patients achieving complete remission in 8 cases. UST also showed efficacy in 7 patients without IBD [2]. We did not find any data regarding UST trough level measurements in PG treatment.
In our patient serum UST trough concentration before PG onset was 1.93 µg/ml. During re-induction, it increased to 8.35 µg/ml 4 weeks after the first infusion and was 7.28 µg/ml after 8 weeks. PG showed a complete remission 20 weeks after onset.
Conclusion: Intravenous UST dose intensification could be an option for severe cases of pyoderma gangrenosum although further studies correlating ustekinumab trough levels with clinical response are needed.

References

[1] Rogler G, Singh A, Kavanaugh A, Rubin DT. Extraintestinal Manifestations of Inflammatory Bowel Disease: Current Concepts, Treatment, and Implications for Disease Management. Gastroenterology. 2021;161(4):1118–32.
[2] Guillo L, Danese S, Peyrin-Biroulet L. Ustekinumab for Extra-intestinal Manifestations of Inflammatory Bowel Disease: A Systematic Literature Review. J Crohn’s Colitis. 2021;15(7):1236–43.

Introduction

The identification and establishment of reliable biomarkers and early diagnostic system for pancreatic ductal adenocarcinoma (PDAC) are urgently needed. Although blood-based liquid biopsy for comprehensive genomic profiling is useful for cancer diagnosis, we have recently shown that driver gene mutations derived from PDAC can be detected at a higher rate in pancreatic juice (PJ) than blood. We have also reported that some RNAs are carried within extracellular vesicles (EVs) and EV-encapsulated RNAs circulating in body fluid are useful as biomarkers for PDAC diagnosis. We recently developed a unique immunoprecipitation method called EViSTEP™ that utilizes a chelating-based reagent and EV surface marker antibodies (CD9/CD63) to isolate EVs with high purity and high yield.

Aims & Methods

In this study, we aimed to evaluate the usefulness of multi-layer liquid biopsy system by DNA mutation and RNA expression in PJ for cancer diagnosis. PJ samples (n=83; 15 benign hepatopancreatobiliary diseases, 33 low-grade (LG) IPMN, 10 high-grade (HG) IPMN and 25 PDAC) were collected during ERCP examination from each patient in a multicenter study. Cell-free (cf) DNA/RNA and EV-derived RNA (EV RNA) were purified from 2 ml of each PJ. Digital PCR was performed for driver gene mutation analysis (4 types of KRAS and 2 types of GNAS), as well as expression analysis of 10 long non-coding RNAs (lncRNA, e.g., HEVEPA, LINC02280) in cfRNA and EV RNA. The diagnostic performance of pancreatic cancer (PDAC+HG-IPMN) was statistically analyzed after normalizing RNA expression with two reference genes (ACTB/B2M).

Results

Logistic regression analysis (objective variables; PDAC+HG IPMN and others) with the KRAS and GNAS variant allele frequency (VAF), and RNA expression as factors was performed. The Area Under Curves (AUC) in Receiver Operating Characteristic (ROC) curve analysis for PDAC+HG IPMN diagnosis were 0.490-0.74 for KRAS mutations, 0.475-0.554 for GNAS mutations, 0.451-0.654 for cfRNA expressions and 0.362-0.639 for EV RNA expressions. Among them, the factors with relatively high AUC were KRASG12V (0.728), KRASG12R (0.687), cfRNA RP11-750H9.5/ACTB(0.654), EV RNA CRNDE/ACTB(0.633). The AUC values of the combinations, [KRASG12V, KRASG12R, cfRNA RP11-750H9.5/ACTB and EV RNA CRNDE/ACTB] and [the aforementioned four factors and CA19-9], were 0.876 and 0.885, respectively in terms of discriminating PDAC+HG IPMN. Moreover, concerning the diagnosis of Stage 0/I PDAC, the AUC values of EV HEVEPA, CA19-9, and the combination [EV HEVEPA and CA19-9] were 0.693, 0.746 and 0.84, respectively, suggesting that EV HEVEPA would be reliable biomarker for early detection of PDAC.

Conclusion

By incorporating cell-free lncRNA and EV lncRNA expression analysis into DNA mutation analysis in PJ samples could be expected to improve the diagnostic performance of pancreatic cancer. Liquid biopsy using PJ would predict the presence of neoplastic lesions with high probability and has a powerful potential for early diagnosis. Establishing the multilayer gene panel using these DNA and RNA has the potential to improve the early diagnostic accuracy for pancreatic cancer, a disease that exhibits significant diversity.

Disclosure

Grants for commissioned/joint research: Hitachi High-Tech Corporation (KT, YM), H.U. Group Research Institute G.K. (KT)