A Pharmacological Batch of Mongersen that Downregulates Smad7 is Effective as Induction Therapy in Active Crohn's Disease: A Phase II, Open-Label Study

Abstract

Background: A recent phase III trial did not confirm the previous clinical and endoscopic improvements seen in patients with Crohn's disease (CD) receiving Mongersen, an oral Smad7 antisense oligonucleotide. Factors accounting for such a discrepancy are unknown.

Objective: Our objective was to further assess whether Mongersen was effective as induction therapy in active CD and evaluate the in vitro inhibitory effect of various batches of Mongersen used in the previous and present trials on Smad7 expression.

Methods: In a phase II, open-label study, 18 patients with active CD (Crohn's Disease Activity Index [CDAI] score > 220 and evidence of endoscopic lesions) received Mongersen 160 mg/day for 12 weeks. The rates of clinical remission, defined as CDAI < 150, and clinical response, defined as a CDAI score decrease ≥ 100, were evaluated at week 4, 8, and 12. The fraction of circulating CCR9-expressing leukocytes was assessed by flow cytometry. Smad7 expression was evaluated in the human colorectal cancer cell line HCT-116 transfected with different batches of Mongersen using real-time polymerase chain reaction (PCR) and Western blotting, RESULTS: The proportions of patients experiencing clinical remission were 38.9%, 55.6%, and 50.0% at week 4, 8, and 12, respectively. At the same time points, the rates of clinical response were 72.2%, 77.8%, and 77.8%, respectively. Mongersen reduced the percentages of CCR9-expressing CD45+ cells. The batch of Mongersen used in this study, but not two batches used in the phase III study, inhibited Smad7 expression in HCT-116 cells.

Conclusions: The present findings support the clinical benefit of Mongersen in active CD and show that various batches manufactured during the GED0301 program differ in their ability to inhibit in vitro Smad7.

Trial registration number: NCT02685683; EudraCT 2015-001693-18.

Conflict of interest statement

Giovanni Monteleone holds a patent for the use of Smad7 antisense oligonucleotides in CD. Irene Marafini, Carmine Stolfi, Edoardo Troncone, Elisabetta Lolli, Sara Onali, Omero Alessandro Paoluzi, Massimo C. Fantini, Livia Biancone, Emma Calabrese, Antonio Di Grazia, Ivan Monteleone, Marco Vincenzo Lenti, and Antonio Di Sabatino have no conflicts of interest that are directly relevant to the content of this article.

Figures

Fig. 1

Percentages of patients a experiencing clinical remission, defined as a Crohn’s Disease Activity Index score of < 150 at week 4, 8, and 12 following Mongersen treatment and b who had a clinical response, defined by a 100-point decrease in the Crohn’s Disease Activity Index score at week 4, 8, and 12 following Mongersen treatment

Fig. 2

Mean changes in a CDAI score from baseline at week 4, 8, and 12 and b PRO2 score from baseline at week 4, 8, and 12. Error bars show standard error of the mean. All 18 enrolled patients were included in the analysis (intention-to-treat population; last observation carried forward analysis). CDAI Crohn’s Disease Activity Index, PRO2 two-item patient-reported outcomes

Fig. 3

Percentages of circulating CCR9-expressing a CD45+ cells and b CD45+CD3+ cells at baseline and at week 12 following Mongersen treatment in patients experiencing clinical remission/response at week 12. Each point in the graph indicates the fraction of positive cells in a single patient as evaluated by flow cytometry. Horizontal bars indicate the median values. Representative histograms are also shown for each subset of cells

Fig. 4

In vitro effects of different batches of Mongersen on Smad7 expression and cell growth. a Effect of different batches of Mongersen on Smad7 mRNA expression. HCT-116 cells were transfected with either lipofectamine only (control) or the indicated batches of Mongersen as described in Sect. 2. Smad7 mRNA transcripts were evaluated using real-time polymerase chain reaction. Levels were normalized to β-actin. Values are mean ± standard error of the mean of three experiments. NP901 vs. control, **P < 0.01; NP004 vs. control, ***P < 0.001. b Effect of different batches of Mongersen on Smad7 protein expression. HCT-116 cells were transfected with either lipofectamine only (control) or the indicated batches of Mongersen as described in Sect. 2. Whole-cell extracts were prepared and analyzed for Smad7 expression by western blotting. β-actin was used as a loading control. One of at least three representative experiments is shown. c Quantitative analysis of Smad7/β-actin protein ratio in total extracts of HCT-116 cells transfected as indicated in (b), as measured by densitometry scanning of western blots. Values are expressed in arbitrary units and are the mean ± standard error of the mean of three experiments. NP901 vs. control, **P < 0.01; NP004 vs. control, ***P < 0.001. d Effect of different batches of Mongersen on HCT-116 cell growth. Cells were transfected with either lipofectamine only (control) or the indicated batches of Mongersen and then labeled with carboxyfluorescein diacetate succinimidyl ester as described in Sect. 2. Cell proliferation was assessed by flow cytometry. NP004 or NP901 vs. control, ***P < 0.001