Preliminary results from Lexicon’s Phase 1 studies of LX2931 and LX7101 for RA

Lexicon Pharmaceuticals, Inc. (Nasdaq: LXRX), a biopharmaceutical company focused on discovering breakthrough treatments for human disease, today reported preliminary results from Phase 1 studies of LX2931 and LX7101.

The Phase 1 study of LX2931, an inhibitor of sphingosine-1-phosphate lyase, was a dose-ranging study to explore higher doses of LX2931 in patients with rheumatoid arthritis. The study involved 10 patients with rheumatoid arthritis, eight of whom were randomized to LX2931 and two to placebo.  The primary endpoint in the study was an evaluation of the safety and tolerability of escalating doses of LX2931 compared with placebo over 12 weeks in subjects with active rheumatoid arthritis.  Secondary endpoints included pharmacokinetic and disease activity measures. 

Patients in the study received increasing doses over the course of the study, beginning at 50 mg QD and escalating to 500 mg QD.  LX2931 was well-tolerated at all doses evaluated, with no serious adverse events and no withdrawals due to adverse events. Seven of eight patients on LX2931 achieved drug trough levels greater than 60 ng/ml, a pharmacokinetic measure which a post-hoc analysis of data from a prior Phase 2 study of LX2931 had suggested was associated with better responses in American College of Rheumatology (ACR) measures in the study.  Six of the eight LX2931-treated patients experienced a drop from baseline in the DAS28 score of greater than or equal to 1.2, as did both placebo patients.  ACR20 and ACR50 responses were achieved at varying frequencies in both LX2931-treated and placebo patients, but two of eight patients dosed with LX2931 achieved an ACR70 response during the course of the study, compared to none on placebo.

The Phase 1 study of LX7101, an inhibitor of LIM domain kinase 2 (LIMK2), was a first-in-man study evaluating two doses of LX7101 in glaucoma patients.  The study involved 63 patients with glaucoma randomized among two doses of LX7101 (0.125% solution and 0.25% solution, each given as an eye drop) or vehicle.  The primary endpoint in the study was an evaluation of the safety and tolerability of LX7101 compared with vehicle over two weeks.  Secondary endpoints included measures of intraocular pressure (IOP), taken at multiple time points on day -1, day 1, day 7 and day 14.

Patients in the study received a single daily dose of LX7101 or placebo during the first week of the study and two daily doses during the second week. LX7101 was well-tolerated at all doses evaluated, with no serious adverse events and no withdrawals due to adverse events. Mean IOP changes from baseline at day 14 for each LX7101 dose arm compared to vehicle at eight hours post-dose were 3.18 mmHg for 0.125% and 2.32 mmHg for 0.25%, compared to 0.40 mmHg for vehicle (p=0.007 for 0.125% and p=0.028 for 0.25%). Reductions from baseline at day 14 in the diurnal mean IOP, representing mean changes across all daily time points, were 3.37 mmHg for 0.125% and 3.52 mmHg for 0.25%, compared to 2.17 mmHg for vehicle (also statistically significant).

"We believe the results of these studies offer a potential path for evaluating the efficacy of higher doses of LX2931 and demonstrate the potential utility of LX7101's novel mechanism of action," said Dr. Arthur T. Sands, president and chief executive officer of Lexicon.  "We will be evaluating the results of these studies internally and with prospective partners in determining next steps for these programs."