The Safety and Biological Activity of OTT166, a Novel Topical Selective Integrin Inhibitor for the Treatment of Diabetic Eye Disease: A Phase 1b Study.

BACKGROUND AND OBJECTIVES: To evaluate the safety, tolerability, and biological activity of a topical selective integrin inhibitor (OTT166) eyedrop administered BID for diabetic retinopathy (DR) and diabetic macular edema (DME). STUDY DESIGN/MATERIALS AND METHODS: A prospective, multicenter, randomized, double-masked Phase 1b study. Subjects with nonproliferative DR and DME with central subfield thickness (CST) &gt; 325 microns were randomized to OTT166 eyedrops (2.5% or 5%) BID for 28 days. Subjects were followed for an additional 28 days after treatment cessation. RESULTS: Forty-four subjects were enrolled. No drug-related serious adverse events (SAEs) and two drug-related adverse events (AEs) were reported. OTT166 was well-tolerated with no evidence of ocular toxicity. Best-corrected visual acuity (BCVA) remained stable. Mean central retinal thickness (CRT) overall was variable: +12.8/+1.8 microns at Day 28 (end of treatment) and -50.3/+5.5 microns at Day 56 (end of study) for the 2.5% and 5% groups, respectively. Median CRT overall demonstrated consistent reduction by end of study: -39.0/-16.5 microns for the 2.5% and 5% groups, respectively. Median responses were greater in the treatment-naïve group (-41.5/-26.0 microns for the 2.5% and 5% groups, respectively). Thirty-seven percent of 'responder' subjects exhibited a mean reduction in CRT of 46.6 microns on optical coherence tomography (OCT) at end of treatment (Day 28) which persisted to end of the study (Day 56) - mean reduction of 67.4 microns, suggesting a durable effect. CONCLUSION: OTT166 eyedrops were safe, well-tolerated, and demonstrated biological activity in 37% of responders. These results warrant further evaluation of OTT166 eyedrops. <b>[<i>Ophthalmic Surg Lasers Imaging Retina</i> 2022;53:553-560.]</b>.

A randomized, double-blind, placebo-controlled trial of injected capsaicin for pain in Morton's neuroma.

Intermetatarsal neuroma or Morton's neuroma is a painful condition of the foot resulting from an entrapment of the common digital nerve typically in the third intermetatarsal space. The pain can be severe and especially problematic with walking. Treatment options are limited and surgery may lead to permanent numbness in the toes. Capsaicin, the pungent ingredient of hot peppers, produces analgesia by inducing retraction of nociceptive afferents from the area of innervation and is effective in treating certain neuropathic pain disorders. A randomized double-blind placebo-controlled study was conducted to test the efficacy, tolerability, and safety of a single 0.1 mg dose of capsaicin vs placebo injected into the region of the neuroma. A total of 58 subjects diagnosed with Morton's neuroma with foot pain ≥4 (0-10 numerical pain rating scale) were injected with 2 mL of lidocaine into the intermetatarsal space proximal to the neuroma to provide local anesthesia. After 5 minutes, 0.1 mg capsaicin or placebo was injected into the intermetatarsal space containing the painful neuroma. Average foot pain was rated for 2 weeks before through 4 weeks after injection. At weeks 1 and 4, the decrease in pain was significantly greater in the subjects treated with capsaicin (P = 0.021 and P = 0.019, respectively). A trend toward significance was noted at weeks 2 and 3. Improvements in functional interference scores and reductions in oral analgesic use were also seen in the capsaicin-treated group. These findings suggest that injection of capsaicin is an efficacious treatment option for patients with painful intermetatarsal neuroma.

Randomized control trial of topical clonidine for treatment of painful diabetic neuropathy.

A length-dependent neuropathy with pain in the feet is a common complication of diabetes (painful diabetic neuropathy). It was hypothesized that pain may arise from sensitized-hyperactive cutaneous nociceptors, and that this abnormal signaling may be reduced by topical administration of the α(2)-adrenergic agonist, clonidine, to the painful area. This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. Nociceptor function was measured by determining the painfulness of 0.1% topical capsaicin applied to the pretibial area of each subject for 30minutes during screening. Subjects were then randomized to receive 0.1% topical clonidine gel (n=89) or placebo gel (n=90) applied 3 times a day to their feet for 12weeks. The difference in foot pain at week 12 in relation to baseline, rated on a 0-10 numerical pain rating scale (NPRS), was compared between groups. Baseline NPRS was imputed for missing data for subjects who terminated the study early. The subjects treated with clonidine showed a trend toward decreased foot pain compared to the placebo-treated group (the primary endpoint; P=0.07). In subjects who felt any level of pain to capsaicin, clonidine was superior to placebo (P<0.05). In subjects with a capsaicin pain rating ⩾2 (0-10, NPRS), the mean decrease in foot pain was 2.6 for active compared to 1.4 for placebo (P=0.01). Topical clonidine gel significantly reduces the level of foot pain in painful diabetic neuropathy subjects with functional (and possibly sensitized) nociceptors in the affected skin as revealed by testing with topical capsaicin. Screening for cutaneous nociceptor function may help distinguish candidates for topical therapy for neuropathic pain.