In this class it is worthwhile to highlight the small non-peptide molecules LM22A-24 and LM11A-31 developed by Longo and Massa. Through the modulation of p75NTR activity, these compounds downregulate degenerative and upregulate trophic signaling. In particular, LM11A-31 was found to inhibit several pathophysiological mechanisms involved in AD and related to p75NTR. Oral administration in AD mice models reduces degeneration of cholinergic neurites. Furthermore, by a direct activation of p75NTR signaling and inhibition of apoptotic pathway, it improves motor function in a spinal cord injury (SCI) mice model and leads to an antiapoptotic effect in mice after traumatic brain injury (TBI). In February 2017, a phase 2 clinical trial started focusing on the evaluation of the safety of LM11A-31 in mild to moderate AD (NCT03069014). This study was completed in June 2020, but the results have not been published yet.
Another drug belonging to the class of p75NTR antagonists is THX-B, which inhibits NGF-p75NTR binding and prevents the death of RGCs in axotomy and glaucoma. In addition, in combination with LM22A-24, THX-B delays the loss of retinal structure, prevents RGC degeneration and preserves ganglion cell layer-inner plexiform layer thickness with a better efficacy compared to LM22A-24. Finally, a p75NTR antagonist, EVT901, was able to improve functional outcomes in two models of traumatic brain injury. Furthermore it was found to reduce inflammation in vivo in the TGFAD344 rat model of AD.