Lexicon pain drug advances after clearing early clinical test

A phase 1a trial of Lexicon Pharmaceuticals’ LX9211 has met its primary objectives. The study found the AAK1 inhibitor was well tolerated, teeing Lexicon up to advance the neuropathic pain prospect.

Lexicon licensed LX9211 from Bristol-Myers Squibb in 2016 after working with the Big Pharma to characterize the AAK1 target through a neuroscience drug discovery alliance. Since taking charge of the program, Lexicon has wrapped up IND-enabling studies and put LX9211 through an early-phase test designed to assess safety and identify the maximum tolerated dose.

Now, Lexicon has data from that early-phase test. Lexicon is yet to share a close look at the data but painted the outcome of the trial as a surprise-free success in its summary of the findings.

“The initial clinical data for LX9211 confirms the drug candidate’s preclinical profile," Lexicon R&D Executive Vice President Praveen Tyle said in a statement. "LX9211 was well tolerated with predictable pharmacokinetics. At doses tested, drug levels of LX9211 were at biologically relevant concentrations and support the therapeutic potential of this highly selective inhibitor of AAK1.”

Lexicon generated the data in a clinical trial that enrolled healthy volunteers and grouped them into 10 cohorts that received daily doses of LX9211 ranging from 5 mg to 200 mg. According to Lexicon, the pharmacokinetics support once-daily dosing, at most, and were dose proportional across almost all of the evaluated range. No drug-related serious adverse events were reported. 

Boosted by the findings, Lexicon is planning to move LX9211 into a multiple ascending dose study in the first quarter of next year. The trial will move Lexicon a step closer to learning whether LX9211 can treat neuropathic pain without causing addiction and other complications associated with the use of existing painkillers. 

Lexicon identified AAK1 as a target that could yield drugs with such properties by testing 3,097 mouse knockout lines. The research led to the characterization of AAK1 and to the agreement with Bristol-Myers, which gave Lexicon full rights to LX9211 in return for regulatory and commercial milestones that start with the initiation of a phase 2 trial.