ADL-5747 was a novel opioid analgesic drug, however its development was halted because it did not pass phase II trials.
Mechanism of action
ADL-5747 is an opioid analgesic, it works by activating opioid receptors. However, unlike "classical" opioids such as morphine, it is selective for the delta receptor.
In tests done on mice, ADL-5747 was able to reduce pain in an efficient way. This compound does not seem to cause receptor internalization. References