Effect of andecaliximab (anti-MMP9) on proteolysis of IL-7 in vitro, TCR diversity in mice, and serum IL-7 in gastric cancer patients in combination with chemotherapy.

101 Background: Andecaliximab (andeca) is a monoclonal antibody that selectively inhibits matrix metalloproteinase 9 (MMP9). IL-7 selectively enhances the proliferation and survival of naïve, memory, and effector T-cells (but not regulatory T-cells) in the periphery. Previous clinical trials with systemic recombinant IL-7 therapy increased TCR diversity. In the disease setting, elevated circulating IL-7 may be due to a compensatory increase in IL-7 production as demonstrated in mice upon inhibition of IL-7 signaling. Methods: An in vitro screen, in which recombinant active human MMP9 was incubated with > 140 human recombinant folded proteins, identified IL-7 as the most efficient substrate of MMP9. Results: IL-7 proteolysis occurred between A128:L129. IL-7 proteolysis altered the global protein structure, evidenced by a loss of cooperative unfolding observed with intact IL-7 (intrinsic fluorescence, Tm = 59.3o C). Mouse MMP9 proteolyzed mouse IL-7 in vitro. In the orthotopic syngeneic NeuT mouse model, MMP9 inhibition reduced tumor growth (p = 0.0005). In a 7-day NeuT study, anti-MMP9 alone improved TCR diversity (decreased clonality) within tumor-infiltrating T-cells (Dunnett’s p = 0.0083). Further, anti-MMP9 and anti-PDL1 co-treatment promoted an increase in CD3+ cells (p = 0.01), CD4+ T cells (p = 0.006), and CD8+ T cells (p = 0.013) concomitant with a decrease in tumor-associated CD25+ FoxP3+ regulatory T cells (p = 0.04) in the tumor. In gastric cancer patient serum, pro-MMP9 (p < 0.0001), active MMP9 (p < 0.0001), and IL-7 (p < 0.0001) were higher than healthy controls. Serum IL-7 levels were normalized upon treatment with andeca plus mFOLFOX6 (N = 40; FDR-corrected p < 0.001) in a Phase I gastric cancer study. Conclusions: MMP9 proteolyzed IL-7 in vitro. Specific MMP9 inhibition in a mouse tumor model improved TCR diversity. Andeca +mFOLFOX6 therapy normalized serum IL-7 levels, which could be due to andeca, chemotherapy, or disease resolution. The functional implications of IL-7 proteolysis by MMP9 in gastric cancer are currently under investigation.

New Perspectives in the Treatment of Advanced Gastric Cancer: S-1 as a Novel Oral 5-FU Therapy in Combination with Cisplatin

Oral fluoropyrimidines have been available for more than 10 years. Capecitabine is well established in treating solid tumors in Europe. S-1 (Teysuno®), an oral formulation containing the 5-fluorouracil (5-FU) prodrug tegafur and the two enzyme modulators gimeracil and oteracil, has not been available in non-Asia countries until recently. In Japan, S-1 in combination with cisplatin is the recommended first-line treatment in patients with gastric cancer. In Europe, the first trials with S-1 were disappointing due to high unacceptable incidences of adverse events. Pharmacokinetic studies showed differences in Asian and Caucasian patients; therefore, a new non-Asian study program was initiated, which led to the pivotal phase 3 trial First-Line Advanced Gastric Cancer Study (FLAGS). In FLAGS, 1,053 patients with advanced gastric cancer from 24 non-Asian countries were enrolled. S-1 plus cisplatin showed no overall survival (OS) benefit when compared to 5-FU plus cisplatin. The primary endpoint superior OS was not met but better tolerability was shown. A post hoc noninferiority OS and safety analysis showed that S-1 plus cisplatin has the same efficacy as 5-FU plus cisplatin but a more favorable safety profile. This led to the approval of S-1 in combination with cisplatin in gastric cancer in Europe in 2011. This article reviews the mode of action of S-1, pivotal study results from an EU point of view, and future perspectives.