Praveen Tyle
Analyst · Citigroup. Your line is open, please ask your question
Thank you, Lonnel. LX9211 is a potent, orally delivered, selective small molecule inhibitor of AP2-associated kinase, which I’ll reference as AAK1, which is a pathway we believe may have utility in reducing neuropathic pain while avoiding the addictive downsides of the opioid pathways. LX9211 was discovered by scientists working within our drug discovery alliance with Bristol-Myers Squibb. And we now wholly-owned all rights to LX9211 as well as any additional compounds acting through AAK1 pathway that we may develop. As you can see on this chart, we have already initiated a Phase 2 proof-of-concept study in diabetic peripheral neuropathy pain. And we plan to initiate an additional Phase 2 proof-of-concept study in post-herpetic neuralgia by the end of this year. We expect that both of these Phase 2 studies will readout by the end of next year. Neuropathic pain affects a large portion of the population within a worldwide market of approximately $6.4 billion in estimated sales expected for 2020. The worldwide market is expected to grow at over 13% a year to $13.2 billion by 2026. There is estimated to be a prevalence of approximately 12 million people worldwide suffering from DPNP and 600,000 people suffering from PHN in 2026. Despite neuropathic pain, affecting millions of people, there remains a high level of unmet need for those suffering from that condition. The current approved therapies are limited by a lack of efficacy compounded by disruptive side effects. As a result, many people turn to opioids to experience some level of relief, which of course carry their own risks of potential abuse and addiction. We feel that LX9211 towards inhibition of AAK1 independent from the opioid pathway has the potential to overcome many of the shortcomings of current therapies and could become a welcome new innovation for those suffering from neuropathic pain on a routine basis. So let's talk a little bit about why we are so interested in AAK1 as an innovative pathway for neuropathic pain. The discovery of AAK1 as a potential target for neuropathic pain occurred in the course of our multi-year discovery and research program, we conducted about a decade ago called the Genome5000 project. In that initiative, we studied the phenotypes of approximately 5,000 different knockout mouse lines and identified the AAK1 knockout mice as exhibiting the most compelling phenotype for neuropathic pain among all the genes we studied here at Lexicon. Our preclinical data for LX9211 has demonstrated excellent central nervous system penetration and reductions in pain behavior in animal models of neuropathic pain. I will take you through some of our preclinical findings for LX9211 in these animal models shortly. But what is very important is that we have conducted several preclinical tests to confirm LX9211’s independence from the opioid pathway. And so far, we have found no concerns around addictive potential with LX9211. We have conducted single and multiple ascending dose Phase 1 clinical studies in healthy volunteers to study the safety, tolerability and pharmacokinetics of LX9211. These studies support the preclinical profile we had obtained in our laboratories. LX9211 was well tolerated with dose proportional pharmacokinetics that was supportive of once-daily dosing. There were no drug-related serious adverse events and the most common adverse events were transient, headaches and dizziness. Overall, we feel LX9211 represents an innovative potential approach to treat neuropathic pain without the addictive potential of many of the current therapies and treatments. Let me show you some of the preclinical data supporting our view that LX9211 may be beneficial for people suffering from diabetic peripheral neuropathic pain, and post-herpetic neuralgia. With diabetic peripheral neuropathic pain, people living with diabetes often develop nerve damage, which cause painful debilitating symptoms most often in their legs and feet. It is estimated that 60% to 70% of people with diabetes will develop peripheral neuropathy at some point in their life. On this slide, you will see the effect of LX9211 in the gold-standard diabetic peripheral neuropathic pain models in rat also called STZ-model. In this model, streptozotocin, STZ is used to induce diabetes in rats, and then tests are performed to evaluate the rats’ sensitivity to mechanical allodynia, which is a condition associated with diabetes where even slight touch can cause a painful sensation. This graph is book-ended with the brown and purple lines. The brown line represents the rats in which diabetes was induced, while the purple line represents the control rats without diabetes and with normal sensitivity to touch. The rats along the brown line are feeling the full effect of neuropathic pain from their diabetes, and they feel pain with any type of touch as shown by 0% inhibition of mechanical allodynia. The rats along the purple line are not feeling any effect of neuropathic pain or sensitivity to touch as shown by 100% inhibition of mechanical allodynia. The lines in between these two extremes show the effect of LX9211 on the diabetic rat. As you can see, there is a clear dose response to LX9211 that enables these diabetic rats to experience it's statistically higher degree of touch without pain at the 1 milligram and 3 milligram per kilogram levels. By way of comparison in the same experiment, gabapentin was administered at 100 milligram per kilogram and resulted in a similar response as the 1 milligram and 3 milligram per kilogram levels of LX9211. So we were able to achieve a similar level of efficacy at a much lower dose with LX9211. More importantly, at this level of dosing, we saw no motor impairment in the rats and no impairment of performance in a cognition model, which are the two significant side effects of gabapentin. We have advanced LX9211 into a Phase 2 proof-of-concept trial in DPNP. This trial is a double blind placebo controlled parallel group study that is expected to enroll approximately 300 patients from 30 U.S. sites. Patients will be randomized to one of the three arms, placebo, 100 milligram initial dose followed by 10 milligram maintenance dose and 200 milligram initial dose followed by 20 milligram maintenance dose of LX9211 with a 1-1-1 randomization. The primary endpoint has changed from baseline to week six in average daily pain score, a very standard symptom measurement tool used in most of the neuropathic pain trials. The first patient was dosed during third quarter of this year and we expect results in the fourth quarter of 2021. We have taken steps to mitigate the strong placebo effect that is characteristics of studies in diabetic peripheral neuropathy pain, including studying a large number of patients over a long treatment period, conducting the trial exclusively in United States and otherwise designing the trial with the potential placebo effect in mind. Now let's turn our attention to the second indication post-herpetic neuralgia. Post-herpetic neuralgia is the most common complication of shingles. And usual who contract shingles will often be left with nerve damage that causes burning sharp pain long after the rash and blisters of shingles disappear. People of an older age and people with greater acute pain, greater rash severity or on immunosuppressive therapies are more likely to develop PHN. This condition can last months to years. On this slide, you will see the effect of LX9211 in post-herpetic neuralgia model in rats. And this model varicella zoster, which is the virus that causes shingles is introduced to the rats. Rats are nocturnal by nature and prefer to stay in the dark, usually only entering the light when under duress. In this model, we looked at the time that rats spend in dark versus the light. After placing the rat in the test chamber, the rat was stimulated on the face with a filament every 15 seconds. We measured the time rats spend in the dark over five minute intervals or 300 seconds, the rats represented by the white circles dotted line have not been administered the virus and therefore act normally. As you can see in both graphs, they spend nearly all their time in the dark. The rats represented by blue circles dotted line had been administered the virus and therefore are in pain from shingles and spend large amounts of time in the light. On the left graph, we tested the effect on the rats of a single dose of our drug LX9211, seven days post virus infection. As you can see the rats which were treated with our drug LX9211 acted similarly to the rats that were not infected. On the right graph, we tested the effect on rats of seven daily doses of LX9211, 14 days post virus infection. In this case, the rats which were treated with our drug LX9211 acted nearly identical to the rats that were not infected and you can see great separation from the untreated rats. By way of the comparisons, we ran the same test head-to-head with gabapentin at 100 milligram per kilogram. Once again, we have the single doses of LX9211 and gabapentin on the left and multiple doses of LX9211 and gabapentin on the right. The gabapentin single-dose resulted in a similar response as a single dose of 30 milligram per kilogram of LX9211, both drugs provided a statistically significant improvement in time in the dark as compared to the untreated rats. In the multiple dose administration involving seven doses of our drug LX9211 and gabapentin, we saw further separation, when comparing gabapentin treated rats to LX9211 treated rats, the pain response was significantly better in our LX9211 treated rats. With LX9211, we were able to achieve a similar or potentially superior level of efficacy at both single dose and multiple dose and using a much lower dose than gabapentin. We are very encouraged by the preclinical data and we will be initiating an additional Phase 2 clinical study of LX9211 in post-herpetic neuralgia. In general, PHN has a lower placebo effect and outcomes are more straightforward. The PHN trial will be a small pilot study with two arms only, placebo versus 200 milligram initial dose followed by 20 milligram maintenance dose daily. We plan to enroll approximately 74 patients in approximately 30 sites globally. The primary endpoint has also changed from baseline to week six average daily pain score and we expect the first patient to be dosed later this year. Overall, we feel that our drug LX9211 has the potential to show significant benefits for people suffering from DPNP and PHN and we look forward to completing and reporting results from both of these studies towards the end of next year. With that, I would like to turn the call over to Jeff Wade to discuss our financial results. Jeff?