PureTech Health plc announced the initiation of a clinical study of LYT-100 (deupirfenidone), PureTech's wholly-owned therapeutic candidate for the potential treatment of idiopathic pulmonary fibrosis (IPF), to support its registration-enabling package. LYT-100 is a selectively deuterated form of pirfenidone. Pirfenidone is a proven therapy for IPF, a devastating condition where the favorable tolerability, safety and potentially higher exposure of LYT-100 could have an important impact on patient adherence and outcomes.

IPF is a chronic orphan condition that causes progressive scarring of the lungs, and approximately 130,000 people in the U.S. are living with the disease. The prognosis of IPF is poor, with the median survival after diagnosis generally estimated at two to five years. Pirfenidone is approved by the U.S. Food and Drug Administration (FDA) for IPF, yet there are serious limitations to pirfenidone's clinical use, primarily due to severe gastrointestinal (GI)-related tolerability issues.

LYT-100 isdesigned to retain the potentand clinically validated anti-fibrotic and anti-inflammatory activity of pirfenidone buthas demonstrated a highly differentiated pharmacokinetic (PK) profile that has translated into improved tolerability in PureTech's ongoing clinical development program. To date, LYT-100 has been studied in more than 400 subjects and demonstrated a favorable safety and tolerability profile. In acrossover study in healthy older adults with similar median age to patients with IPF, PureTech showed that approximately 50% fewer subjects experienced GI-related adverse events (AEs) with LYT-100 compared with pirfenidone (17.4% vs.

34.0%) and substantiallyfewer subjects experienced AEs with LYT-100 vs. pirfenidone. PureTech also recently showed that LYT-100 can be safely dosed with a higher total drug exposure than the currently approved dose of pirfenidone, which could translate into improved efficacy over pirfenidone.

The global, randomized, placebo-controlled registration-enabling study is designed to evaluate the efficacy, tolerability, safety and dosing regimen of LYT-100to help inform the study design for a potential pivotal study and to assess the relative efficacy of LYT-100 compared to pirfenidone. A total of approximately 240 patients will be randomized 1:1:1:1 to receive either one of two dose levels of LYT-100, the FDA-approved dose of pirfenidone, or a placebo. One of the LYT-100 arms will evaluate 550 mg three times a day (TID) of LYT-100, which has previously demonstrated the comparable exposure as the currently approved dose of pirfenidone (801 mg TID), and the other arm will evaluate an 825 mg TID dose of LYT-100, which has demonstrated higher exposure than the currently approved dose of pirfenidone with the potential for improved efficacy.

The primary objective of the study is to demonstrate a statistically significant and clinically meaningful difference in the slope of decline in a measure of lung function, Forced Vital Capacity (FVC), in the LYT-100 treatment arms compared to placebo over 6 months. The study will also evaluate safety, tolerability and the slope of FVC decline in the LYT-100 treatment arms compared to pirfenidone, though this analysis is not powered to demonstrate strict non-inferiority. FVC is an established measure of pulmonary function in IPF and has served as the basis for FDA approval of the currently marketed treatments for IPF.

Topline results from the study are expected by the end of 2023. PureTech's LYT-200 program is also progressing through clinical development. Following the completion of the monotherapy dose escalation portion of the Phase 1 program, PureTech has begun to evaluate weekly doses of LYT-200 and will soon begin to enroll patients in cohorts designed to evaluate LYT-200 in combination with chemotherapy or an anti-PD-1 monoclonal antibody.

Results from the single agent cohorts are expected by the end of 2022, and results from the combination cohorts are expected in 2023. LYT-200 is a fully human IgG4 monoclonal antibody (mAb) designed to inhibit the activity of galectin-9, a key molecule expressed by tumors and immune cells and shown in preclinical models to suppress the immune system from recognizing and destroying cancer cells. The primary objective of the Phase 1 portion of the ongoing adaptive Phase 1/2study is to assess the safety and tolerability of escalating doses of LYT-200 in order to identify an appropriate dose and dosing interval to carry forward into the Phase 2 portion of the trial.

Six cohorts were treated with escalating, bi-monthly doses from 0.2-16 mg/kg, and no dose limiting toxicities were reported to date. Additionally, compelling preclinical data have been generated with LYT-200 in leukemia models, which will be submitted for presentation in a scientific forum. Based on these data, PureTech plans to initiate a study of LYT-200 as a single agent in leukemia patients by the end of 2022.

LYT-100 is one of seven therapeutic candidates within PureTech's Wholly Owned Pipeline. It is a selectively deuterated form of pirfenidone that is designed to retain the potent and clinically-validated anti-fibrotic and anti-inflammatory activity of pirfenidone with a differentiated pharmacokinetic profile that has translated into favorable tolerability, as supported by data from multiple human clinical studies. LYT-100 is being advanced for the potential treatment of conditions involving inflammation and fibrosis, including idiopathic pulmonary fibrosis and breast cancer-related, upper limb secondary lymphedema.

PureTech is also exploring the potential evaluation of LYT-100 in other inflammatory and fibrotic conditions such as myocardial and other organ system fibrosis based on the strength of existing clinical data around the use of pirfenidone in these indications. LYT-200 is a fully human IgG4 monoclonal antibody targeting a foundational immunosuppressive protein, galectin-9, for the potential treatment of solid tumors, including pancreatic ductal adenocarcinoma, colorectal cancer and cholangiocarcinoma, that are difficult to treat and have poor survival rates. PureTech has presented preclinical data demonstrating high expression of galectin-9 across breast cancer, pancreatic and cholangiocarcinoma samples and found that the highest levels of galectin-9 correlated with shorter time to disease relapse and poor survival.

These data suggest that galectin-9 could be significant both as a therapeutic target for a range of cancers and as a cancer biomarker. Preclinical animal and patient-derived organoid tumor models also showed the potential efficacy of LYT-200 and the importance of galectin-9 as a target. LYT-200 is currently being evaluated in a Phase 1/2 adaptive design trial.