YM BioSciences Inc., an oncology company that identifies, develops and commercialises differentiated products for patients worldwide, has announced results of secondary endpoint data from its 99 patient, randomised, placebo-controlled, multi-centre phase IIb trial (DLXLEF-AP4) with AeroLEF.

AeroLEF is a unique, inhaled-delivery composition of free and liposome-encapsulated fentanyl in development for the treatment of moderate to severe pain, including cancer pain. YM previously announced that this trial had successfully achieved its primary endpoint, the summed pain intensity difference/pain relief scores (SPRID4) during the 4 hours from the start of the initial dose of study medication.

The treatment phase of the study began in the post-anesthetic care unit (PACU) after completion of surgery when patients reported a pain intensity score (PI) of at least 2 (moderate pain) on a 4-point verbal rating scale. The clinical trial study period was up to 12 hours and patients were allowed to self-administer AeroLEF to treat up to two additional pain episodes during the study period. For each pain episode, patients were instructed to continue the self-administration of drug until achievement of one of the following endpoints: achievement of effective analgesia, completion of full dose, or onset of dose-limiting side effects. Patients were allowed rescue medication at any time following initiation of study treatment.

For the first dose administered in the PACU, the percentage of patients reporting a pain intensity (PI) score of less than or equal to 1 (mild pain or no pain) at the end of the dosing period with AeroLEF was 59 per cent, a statistically significant difference from placebo (27per cent). As well, the percentage of patients reporting a pain relief (PR) score of more than or equal to 2 (moderate, lots or complete relief) at the end of the dosing period with AeroLEF was 60 per cent also statistically significant compared to placebo (32 per cent).

"These results, from this difficult to treat patient population, confirm that patients are able to personally select doses of opioids to match the quantity of relief to the intensity of each pain event while maintaining a favourable safety tolerability profile," said Diana Pliura, Executive Vice President of YM BioSciences. "This is robust confirmation that our approach not only provides rapid onset of pain relief, but permits extended duration of pain relief, while permitting patients to determine their own dosing requirements, and strongly supports our rationale for the expansion of development of this drug into the U.S."

"Results of this study were significant both clinically and statistically, and highlight the competitive advantages of our product and its potential as a best-in-class treatment for pain," said David Allan, chairman and CEO of YM BioSciences. "We are very pleased that our upcoming trial will be led by a key opinion leader in the US. and look forward to discussions with regulatory authorities on the path to approval for our drug."

The Phase IIb clinical study (DLXLEF-AP4) was a 2-part, multi-centre study to evaluate the efficacy, safety and tolerability of repeated, self-titrated inhalation of AeroLEF for the treatment of acute post-operative pain following orthopaedics surgery.