(S,R)-3-Phenyl-4,5-dihydro-5-isoxasole acetic acid (VGX-1027, GIT-027) is an isoxazole compound that exhibits various immunomodulatory properties. This compound reduced the secretion of IL-1beta, TNF-alpha and IL-10 from purified murine macrophages stimulated "in vitro" with lipopolysaccharide (LPS), and it also modified the signaling pathways induced in these cells by LPS entailing reduced activation of NF-kappaB and p38 MAP kinase pathways along with up-regulation of ERK pathways. The animals receiving VGX-1027 exhibited reduced production of the proinflammatory mediators tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, and inducible nitric-oxide synthase-mediated nitric oxide generation in both pancreatic islets and peripheral compartments. Inovio Pharmaceuticals is developing VGX-1027 for the treatment of inflammatory conditions such as rheumatoid arthritis, type 1 diabetes mellitus, uveitis and ulcerative colitis.

PL-3994 is a novel natriuretic cyclic peptide. It is a receptor-A (NPR-A) and receptor-C (NPR-C) agonist. PL-3994 has high affinity for recombinant human, dog, or rat NPR-As. PL-3994 produced concentration-dependent relaxation of pre-contracted guinea-pig trachea. PL-3994 elicited a potent, concentration-dependent but small relaxation of pre-contracted human precision-cut lung slices. Intratracheal PL-3994 produced a dose-dependent inhibition of the bronchoconstrictor response evoked by aerosolized methacholine, but was without significant effect on cardiovascular parameters. PL-3994 was resistant to degradation by human neutral endopeptidase. PL-3994 was well tolerated in subjects with controlled hypertension. A phase I and phase II trial have been successfully completed with PL-3994 with no safety concerns identified. In phase II study in subjects with hypertension who were receiving >1 antihypertensive medications, a significant reduction in blood pressure compared with placebo was observed. It appears that PL-3994 works synergistically with ACE inhibitors.