Funded Projects

Cholecystokinin B receptor (CCKBR) is a molecule found in the brain that helps regulate anxiety and depression but also influences the development of tolerance to opioids. CCKBR levels are also increased in models of nerve injury-induced (neuropathic) pain. Therefore, targeting CCKBR may offer a new approach to treating neuropathic pain and the associated anxiety and depression. Researchers have developed mouse antibodies that can inactivate CCKBR. However, to be usable in humans without causing an immune response, these antibodies need to be modified to include more human sequences. This project will use a fragment of the CCKBR antibody, modify it with the addition of human antibody sequences, and then select the clones that bind most strongly and specifically to human CCKBR. These will then be tested in cell and animal models of neuropathic pain to identify the most promising candidates for further evaluation in humans.

Patients with severe, intractable chronic pain primarily receive treatment with opioids, and non-opioid treatment options are urgently needed. These patients may be candidates for treatment using other types of pain medications administered via intrathecal injection—that is, injection directly into the fluid-filled space between the membranes surrounding the brain and spinal cord. Intrathecal injection requires much lower medication doses than systemic administration. Centrexion Therapeutics Corporation seeks to develop CNTX-3100, a highly selective and highly potent novel small molecule that activates the nociception receptor (NOPr), for intrathecal administration using a pump approved by the U.S. Food and Drug Administration. In animal studies, such NOPr agonists had powerful analgesic effects when delivered directly to the spinal cord by intrathecal administration. CNTX-3100 has ideal properties for intrathecal delivery and in animal studies provided pain relief and a safety profile that was superior to intrathecally administered morphine. This project will scale up the drug, develop a formulation that ensures a stable product for intrathecal delivery, and conduct preclinical toxicity studies to prepare for a Phase 1 clinical trial.

Neuropathic pain is characterized by neuronal hyperexcitability and spontaneous activity, properties associated with activity of hyperpolarization-activated, cyclic nucleotide-regulated (HCN1-4) channels, the source of the pacemaker current, Ih. Inhibition of HCN1-mediated Ih elicits marked antihyperalgesia in multiple animal models of neuropathic pain, including models for direct nerve injury and chemotherapy-induced peripheral neuropathy, and does so with little or no disruption to either normal pain processing or baseline behaviors and activities. The overall objective is to develop a peripherally restricted HCN1 inverse-agonist as a therapeutic for neuropathic pain. Researchers have generated a novel small molecule that combines an antihyperalgesic HCN1 inhibitor with a motif that controls distribution and membrane presentation and is a potential non-opioid antihyperalgesic treatment for peripheral neuropathic pain.

An extensive literature provides compelling evidence that selective antagonists or negative allosteric modulators (NAMs) of the metabotropic glutamate (mGlu) receptor, mGlu5, have exciting potential as a novel approach for treatment of multiple pain conditions that could provide sustained antinociceptive activity without the serious adverse effects and abuse liability associated with opioids. Researchers have developed a novel series of highly selective mGlu5 NAMs that are structurally unrelated to previous compounds, have properties for further development, and avoid the formation of toxic metabolites that were associated with previous mGlu5 NAMs. Based on existing preclinical models, as well as clinical trial data showing efficacy of an mGlu5 NAM in migraine patients, researchers anticipate that their compounds will have broad-spectrum analgesic activity in patients with a variety of chronic pain conditions.

MNK-eIF4E signaling is activated in nociceptors upon exposure to pain or peripheral nerve injury, promoting cytokines and growth factors and increasing nociceptor excitability, which leads to neuropathic pain. Genetic or pharmacological inhibition of MNK signaling blocks and reverses nociceptor hyperexcitability as well as behavioral signs of neuropathic pain. A clinical phase drug for cancer shows strong specificity as an MNK inhibitor but requires optimization because MNK inhibition in the central nervous system (CNS) may lead to depression, an unacceptable side effect for a neuropathic pain drug. The research team plans a targeted medicinal chemistry and screening campaign directed at generating a MNK-inhibitor-based neuropathic pain treatment with the goal of restricting its CNS penetration while retaining potency, specificity, and in vivo bioavailability and efficacy.