FDA removes clinical hold on RespireRx’s CX1739 ampakine drug

RespireRx plans to start a phase 2A clinical trial by the end of this month to confirm the ability of CX1739 to antagonize the respiratory depressant effects of fentanyl, a potent opioid, without changing its analgesic properties.

The clinical protocol is designed to assess the safety and efficacy of three escalating doses of CX1739 versus placebo when administered before remifentanil, with respiration, analgesia and several other clinical measures being taken after administration of both drugs.

The pharmacological property had earlier been reported for CX717, a predecessor ampakine.

RespireRx Pharmaceuticals president and CEO James Manuso said: "The FDA clearance of our Phase 2A clinical trial of CX1739 provides further validation of RespireRx’s worldwide leadership role in the research and development of next-generation ampakine medicines."

The company completed a phase I human safety and tolerability study with CX1739 involving about 100 subjects, tested at doses up to 1200mg per day.

The plasma half-life of CX1739 was about 8 hours, and the ampakine demonstrated better clinical safety and good tolerability profile.

RespireRx has also undertaken a very small pilot study of a single dose of CX1739 in twenty otherwise healthy sleep apnea patients.

The double-blind, placebo-controlled pilot study was the initial step in the evaluation of potential efficacy of CX1739 in sleep apnea. It was not intended to offer statistical significance in treating sleep apnea.

The company said the study showed that a single dose of CX1739 was able to enhance blood oxygenation, and provided an indication that CX1739 may treat central sleep apnea, since a few patient’s central sleep apnea score was noticeably reduced on the night they received CX1739.