PCS499

Our lead product, PCS499, is an oral tablet that is a deuterated analog of one of the major metabolites of pentoxifylline (PTX or Trental®). PCS499 is classified by FDA as a new molecular entity. PCS499 and its metabolites act on multiple pharmacological targets that are important in a variety of conditions. We have identified Necrobiosis Lipoidica (NL) as our lead indication for PCS499. NL is a chronic, disfiguring condition affecting the skin and the tissue under the skin typically on the lower extremities with no currently approved FDA treatments. NL presents more commonly in women than in men and occurs more often in people with diabetes. Ulceration occurs in approximately 30% of NL patients, which can lead to more severe complications, such as deep tissue infections and osteonecrosis threatening the life of the limb. Approximately 22,000 - 55,000 people in the United States and more than 120,000 people outside the United States are affected with ulcerated NL.

The degeneration of tissue occurring at the NL lesion site may be caused by a number of pathophysiological changes, which has made it extremely difficult to develop effective treatments for this condition. Because PCS499 and its metabolites affect a number of biological pathways, several of which could contribute to the pathophysiology associated with NL, PCS499 may provide a novel treatment solution for NL, a condition for which there are currently no FDA-approved treatments.

On June 18, 2018, the FDA granted orphan-drug designation for PCS499 for the treatment of NL. On September 28, 2018, the IND for PCS499 in NL became effective, such that we could move forward with a Phase 2A multicenter, open-label prospective trial designed to determine the safety and tolerability of PCS499 in patients with NL. The study initially had a six-month treatment phase and a six-month optional extension phase. In December 2019, we informed patients and sites that the study would conclude after the treatment phase and there would no longer be an extension phase. The first enrolled NL patient in this Phase 2A clinical trial was dosed on January 29, 2019 and the study completed enrollment on August 23, 2019. The last patient visit took place in February 2020. Due to COVID-19 related restrictions at certain sites, study closeout and database lock have yet to be completed.

The main objective of the trial was to evaluate the safety and tolerability of PCS499 in patients with NL and to use the collected safety and efficacy data to design future clinical trials. Based on toxicology studies and healthy human volunteer studies, Processa and the FDA agreed that a PCS499 dose of 1.8 grams/day would be the highest dose administered to NL patients in this Phase 2A trial. As anticipated, the PCS499 dose of 1.8 grams/day, 50% greater than the maximum tolerated dose of PTX, appeared to be well tolerated with no serious adverse events reported. All adverse events reported in the study were mild in severity. As expected, gastrointestinal symptoms were the most noted adverse events and reported in four patients, all of which were mild in severity and resolved within 1-2 weeks of starting dosing.

Two of the twelve patients in the study presented with more severe ulcerated NL and had ulcers for more than two months prior to dosing. At baseline, the reference ulcer in one of the two patients measured 3.5 cm2 and had completely closed by Month 2 of treatment. The second patient had a baseline reference ulcer of 1.2 cm2 which completely closed by Month 9 during the patient's treatment extension period. In addition, while in the trial, both patients also developed small ulcers at other sites, possibly related to contact trauma, and these ulcers resolved within one month. However, the other ten patients, presenting with mild to moderate NL and no ulceration, had more limited improvement of the NL lesions during treatment. Historically, less than 20% of all the patients with NL naturally progress to complete healing over many years after presenting with NL. Although the natural healing of the more severe NL patients with ulcers has not been evaluated independently, medical experts who treat NL patients believe that the natural progression of an open ulcerated wound to complete closure would be significantly less than the 20% reported as the maximum percentage of patients who naturally heal over several years after NL presentation.

On March 25, 2020, we met with the FDA and discussed the clinical program, as well as the nonclinical and clinical pharmacology plans to ultimately support the submission of the PCS499 New Drug Application (NDA) in the U.S. for the treatment of ulcers in NL patients. With input from the FDA, we will be designing the next trial as a randomized, placebo-controlled trial to evaluate the ability of PCS499 to completely close ulcers in patients with NL. We initially planned to begin recruiting for the randomized, placebo-controlled trial in the fourth quarter of 2020, but we now expect to begin recruiting patients in 2021 due to the ongoing COVID-19 pandemic. This PCS499 NL study will be a randomized, placebo-controlled Phase 2B study to better understand the potential response of NL patients on drug and on placebo. After obtaining the results from this Phase 2B study, we expect to meet with FDA to discuss our Phase 2B drug and placebo response findings while further discussing the next steps to obtain approval.