Aptinyx leaves investors nursing a painful hangover

The near record-breaking rush of biotech flotations in 2018’s second quarter saw ever-riskier bets jump on the bandwagon. Today one of these, the neurology-focused Aptinyx, reminded investors that wild parties tend to be followed by nasty hangovers as its lead asset, the small-molecule NMDA modulator NYX-2925, flopped in the clinic. In the phase II study in 300 diabetic peripheral neuropathy subjects NYX-2925 failed to reduce neuropathic pain versus placebo. The company said 50mg, the middle of three doses tested, showed the best improvement versus placebo in the primary efficacy measure, reduction from baseline in average daily pain on a numerical rating scale after four weeks, but even this did not come close to showing nominal significance. Aptinyx had been spun out of Naurex when the latter was acquired by Allergan mainly for its peptide chemistry work including the antidepressant project rapastinel. Aptinyx's premium-priced IPO raised $102m, and the stock climbed 26% on the first day of trading; perhaps the most glaring sign of the misplaced expectations is that at its peak, the company was worth over $1bn. A phase II NYX-2925 trial in fibromyalgia is due to read out by mid-2019.