Tarsus Announces Positive Topline Data from Phase 1b Callisto Trial & Initiates Phase 2a Carpo Human Tick Kill Trial Evaluating TP-05, a Novel, Oral Therapeutic for the Prevention of Lyme Disease

Tarsus Pharmaceuticals, Inc. recently announced positive topline results from the completed Phase 1b Callisto trial and the enrollment of the first subject in the Carpo Phase 2a trial. The Callisto and Carpo trials are designed to evaluate TP-05, a novel investigative oral therapeutic for the potential prevention of Lyme disease.

The Callisto trial was a randomized, double-blind, single- and multiple-ascending dose study that evaluated the safety, tolerability, food-effect, and pharmacokinetics (PK) of TP-05 in healthy subjects. Results from the trial showed that TP-05 was well tolerated with no dose-related or drug-related serious adverse events. Pharmacokinetic data from the trial demonstrated rapid absorption and an extended half-life of TP-05 that potentially supports a monthly, or less frequent therapy regimen, supporting its potential as a convenient, rapid onset, prophylactic therapy for Lyme disease. Additionally, exploratory ex-vivo tick kill modeling utilizing serum from TP-05-treated subjects demonstrated potent, rapid killing of adult and nymph ticks.

Tarsus also announced the enrollment of the first patient in the Carpo trial, evaluating TP-05 for the potential prevention of Lyme disease in humans. The Carpo trial is a randomized, double-blind trial that will evaluate the efficacy of TP-05 in killing sterile, non-disease carrying ticks after they have attached to the skin of healthy volunteers, as well as confirm the safety, tolerability, and blood concentration of TP-05.

TP-05 is an oral systemic formulation of lotilaner, a well-characterized anti-parasitic agent that selectively inhibits parasite-specific GABA-CI channels. TP-05 is believed to be the only non-vaccine, drug-based, preventative therapeutic in development designed to kill ticks to potentially prevent Lyme disease transmission.

“Lyme disease is a growing global health concern that may result in serious, often irreversible sequelae if left untreated,” said José Trevejo, MD, PhD, Chief Medical Officer of Tarsus. “As the risk of infection extends into new regions and as overall prevalence grows, identifying a solution to prevent transmission becomes paramount. Tarsus is committed to addressing large, underserved disease areas with unique solutions and our TP-05 investigational program embodies this commitment, as there are no current preventative options for this important disease.”

There are currently no US FDA-approved pharmacological prophylactic options for Lyme disease, which is the most common vector-borne disease in the US. Lyme disease is transmitted through Borrelia burgdorferi infection following the bite of a tick vector. Over 30 million Americans are at high or moderate risk of contracting Lyme disease and there are approximately 300,000-400,000 cases in the US each year.

TP-05 is an oral systemic formulation of lotilaner, a well-characterized anti-parasitic agent that paralyzes and kills ticks that transmit Lyme disease by selectively inhibiting parasite-specific GABA-CI channels. Tarsus is studying TP-05 for the prevention of Lyme disease and has completed a Phase 1b single ascending dose and multiple ascending dose (SAD/MAD) trial to evaluate the safety, tolerability and pharmacokinetics (PK) of TP-05 in healthy volunteers. TP-05 is currently being studied in a Phase 2a clinical trial to evaluate its safety, tolerability, and proof-of-activity. In addition to Lyme disease, Tarsus is also exploring the application of TP-05 for prevention of malaria transmission within an endemic population.

Lyme disease is the most common vector-borne disease in the United States, transmitted to humans by Borrelia burgdorferi infection following the bite of a tick vector. Over 30 million Americans are at high or moderate risk of contracting Lyme disease and there are approximately 300,000-400,000 cases in the US each year. Lyme disease can potentially cause severe, often debilitating symptoms with permanent and irreversible damage. The disease can result in inflammation, nerve, joint and muscle pain and swelling, numbness, shortness of breath and – in severe cases – neurological complications such as facial palsy, vision issues and meningitis, including severe headaches and neck stiffness. Lyme disease can often go undetected and untreated because the ticks are not always noticed before they transmit the disease. People who spend extended amounts of time outdoors in wooded, grassy areas are at higher risk of Lyme disease. Data from the Centers for Disease Control and Prevention (CDC) show that the risk of Lyme disease is spreading to new geographical areas, resulting in a significant need for prophylactic solutions. Currently, there are no FDA-approved pharmacological prophylactic options for Lyme disease.

Tarsus Pharmaceuticals, Inc. applies proven science and new technology to revolutionize treatment for patients, starting with eye care. Tarsus is advancing its pipeline to address several diseases with high unmet need across a range of therapeutic categories, including eye care, dermatology, and infectious disease prevention. Tarsus is studying two investigational medicines in clinical trials. Its lead product candidate, TP-03, is a novel therapeutic which has demonstrated positive results in two pivotal trials for the treatment of Demodex blepharitis, and the New Drug Application has been accepted by the US FDA with a PDUFA target action date of August 25, 2023. TP-03 is also being developed for the treatment of Meibomian Gland Disease, and currently being studied in a Phase 2a clinical trial. In addition, Tarsus is developing TP-05, an oral, non-vaccine therapeutic for the prevention of Lyme disease, which is currently being studied in a Phase 2a clinical trial to evaluate its safety, tolerability, and proof-of-activity.