Yamo Pharmaceuticals Announces Positive Topline Results from Phase 2 Study of L1-79 for the Treatment of the Core Symptoms of Autism

Data shows L1-79 offers a statistically significant improvement compared to placebo in socialization, as well as the investigator- and parent-rated global impression scales

The change over placebo may be one of the largest statistically significant effects observed with the Vineland-3 Socialization standard score for a medication in autism

NEW YORK, July 30, 2024 (GLOBE NEWSWIRE) — Yamo Pharmaceuticals, a clinical stage pharmaceutical company, announced today positive topline results of its Phase 2 clinical trial evaluating the effects of L1-79 in adolescents and young adults with autism spectrum disorder (ASD). The data demonstrated a statistically significant improvement with L1-79 compared to placebo on the Vineland Adaptive Behavior Scale (Vineland-3) Socialization standard score (difference compared to placebo: 7.09, p-value = 0.02) during the first 12-weeks of the study.   The Vineland-3 Socialization Domain is a well-established standardized assessment tool that looks at a person’s coping skills, ability to engage in play, and leisure and interact with others.

In addition, other endpoints, such as the Clinical Global Impression of Severity of Illness (CGI-S) and the Caregiver Global Impression of Change of 3 Most Bothersome Symptoms of ASD (CGI-3P), demonstrated statistically significant improvements with L1-79 compared to placebo, corroborating the Vineland-3 findings. L1-79 was generally safe and well tolerated. There were no serious adverse events or adverse events leading to withdrawal from the trial with L1-79.

“It is very encouraging to see a more than seven-point improvement in the Socialization Domain of the Vineland-3,” said J. Thomas Megerian, MD, PhD, Yamo’s Chief Medical Officer. “We believe that this is one of the largest statistically significant effects observed to-date with a medication in ASD on the Vineland-3 Socialization standard score, representing a clinically meaningful improvement in one of the core domains of function affected by ASD. The Company is eager to meet with the FDA to discuss Phase 3 plans, as well as to file for Breakthrough Therapy designation.”

“We are excited to receive these results in the hope to offer patients and their families a treatment option that can impact the core symptoms of ASD,” said Chuck Bramlage, Yamo’s Chief Executive Officer.

About L1-79
Evidence suggests that dysfunction in the catecholaminergic system may play a role in the core symptoms of ASD. L1-79 is a tyrosine hydroxylase inhibitor expected to modulate the catecholaminergic pathways, and thereby improve the core ASD symptoms. L1-79 was granted Fast Track designation by the FDA in May of 2018.

About the Study
This Phase 2, multi-center, randomized, chronic-dosing (12-week) clinical trial was a two-period placebo-controlled crossover trial that enrolled 58 adolescent and young adults with ASD. Patients were randomized 1:1 to one of two active treatment groups: L1-79 200 mg or 300 mg. On day one of Period 1, participants in each dosing group were randomized to receive either L1-79 or placebo BID for 12-weeks. Following the conclusion of Period 1, participants underwent a six-week washout period and then crossed over into Period 2, in which each participant that received placebo in Period 1 received L1-79 and vice versa BID for another 12-weeks.

Please refer to study identifier NCT05067582 at www.clinicaltrials.gov for additional clinical trial details.

About Autism Spectrum Disorder
Autism spectrum disorder or autism refers to a group of complex neurodevelopment disorders that is defined in the Diagnostic and Statistics Manual of Mental Disorders V (DSM-5) by “difficulties in social communication and social interaction, and restricted and repetitive behavior, interests or activities.” In the U.S., it is estimated that 1 in 36 children have ASD, with boys being 3.8 times more likely to be diagnosed than girlsⁱ. Symptoms of repetitive and characteristic patterns of behavior and difficulties with social-communication and interaction start early in childhood and continue throughout a person’s life.

While the causes of ASD are not known, research suggests that both genes and environment play important roles. Since the severity, specific types of symptoms, and causes of ASD vary between individuals, it is referred to as a “spectrum’ disorder.” Currently there are no approved pharmacological therapies which address the core symptoms of ASD.

About Yamo Pharmaceuticals
Yamo Pharmaceuticals is a clinical stage pharmaceutical company founded in 2015 to develop L1-79, a novel therapy with the potential to improve the core symptoms of ASD. Yamo Pharmaceuticals is a privately held company. More information may be found at www.yamopharma.com.

Safe Harbor Statement
This press release contains “forward-looking statements” concerning the development and commercialization of Yamo Pharmaceuticals’ products, the potential benefits and attributes of such products, and Yamo Pharmaceuticals expectations regarding its prospects. Forward-looking statements are subject to risks, assumptions and uncertainties that could cause actual future events or results to differ materially from such statements. These statements are made as of the date of this press release. Actual results may vary. Yamo Pharmaceuticals undertakes no obligation to update any forward-looking statements for any reason.

Contact Data
Investor and Media Contacts
Chuck Bramlage, CEO
cbramlage@yamopharma.com

Eugene Prahin, CFO
eprahin@yamopharma.com
(212) 610-1570

ⁱ Maenner MJ, Warren Z, Williams AR, et al. Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020. MMWR Surveill Summ 2023;72(No. SS-2):1–14.