@misc{spahn_targeting_delta_2017, author={Spahn, V., Stein, C.}, title={Targeting delta opioid receptors for pain treatment: drugs in phase I and II clinical development}, year={2017}, howpublished = {journal article}, doi = {https://doi.org/10.1080/13543784.2017.1275562}, abstract = {Expert opinion: Many compounds showed potent DOR-specific pain inhibition in preclinical studies. ADL5859 and ADL5747 entered clinical trials and successfully passed phase I. However, in phase II studies the primary endpoint (pain reduction) was not met and further investigation was terminated. A third compound, NP2, is in phase II clinical evaluation and results are pending. These findings suggest a potential of DOR ligands according to preclinical studies. Further clinical research and secondary analysis of unpublished data is needed to identify molecules which are useful in humans.}, note = {Online available at: \url{https://doi.org/10.1080/13543784.2017.1275562} (DOI). Spahn, V.; Stein, C.: Targeting delta opioid receptors for pain treatment: drugs in phase I and II clinical development. Expert Opinion on Investigational Drugs. 2017. vol. 26, no. 2, 155-160. DOI: 10.1080/13543784.2017.1275562}}