Effects of NLS-133, a Potential Non-Hormonal "On-Demand" Male Contraceptive
Effects of NLS-133, a Potential Non-Hormonal "On-Demand" Male Contraceptive, on Semen Volume and Sperm Count in Normal Men: A Double-Blind, Placebo-Controlled Trial
Next Life Sciences
10 participants
Dec 2, 2025
INTERVENTIONAL
Conditions
Summary
NLS-133-CLIN001 is a Phase 2a study designed to assess the safety, tolerability, and effects of NLS-133 (combination of two FDA-approved agents) compared to an active control (FDA-approved pharmacologic agent) or placebo on semen volume and sperm count in 10 in healthy men. Participants will be randomized in a crossover design to receive a single dose of NLS-133, an active control or placebo either 90 or 180 minutes prior to collection of semen. Sperm parameters measured will be count, motility and morphology. A brief questionnaire will be completed by each subject during each treatment cycle that addresses orgasm and ejaculation quality. Safety monitoring will include adverse event reporting, laboratory assessments, and vital signs.
Eligibility
Inclusion Criteria7
- Male, age 18-55.
- Normal physical examination and testicular volume \>15 cc
- No significant medical history that would impact the safety of the study.
- No current use of drugs that comprise NLS-133
- Normal values on baseline hematology, blood chemistry and liver function tests and serum testosterone.
- Normal baseline sperm parameters (semen volume \>1.4 cc, sperm concentration \>15 million/ml, motility \>40% and morphology \>4%).
- Willing and able to comply with all study requirements and procedures.
Exclusion Criteria15
- History or evidence of erectile dysfunction.
- Inability to produce semen samples in clinic setting.
- Significant chronic or acute medical illness.
- Previous or current ethanol or illicit drug abuse.
- Evidence of significant underlying disease (based on results of the physical exam and the routine labs).
- Known infertility or hypogonadism.
- Planned or anticipated use of any prohibited medications during participation in the study. These include use of sex hormones for treatment, testosterone, anabolic steroids, retinoic acid (e.g., Accutane®), vitamin A, other drugs known to inhibit spermatogenesis, opioids, cocaine, methamphetamine, and/or the consumption of \>4 alcoholic beverages daily.
- Presence of moderate-to-severe pulmonary or cardiovascular disease
- Known active hepatitis B, hepatitis C, human immunodeficiency virus (HIV), or COVID-19 infection.
- History of malignancy within 5 years before the Screening Visit, except fully treated and resolved non-metastatic squamous or basal cell carcinoma of the skin.
- Known active chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antifungals, antiparasitics or antiprotozoals during the Screening period.
- Any other acute or chronic medical or psychiatric condition or laboratory abnormality that could increase the risk associated with study participation in the judgment of the investigator would make the participant inappropriate for entry into the study.
- Participation in another investigational clinical trial within the last 30 days.
- Participants who live in detention on court order or on regulatory action.
- Related to sponsor or staff involved in the conduct of the study.
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Interventions
NLS-133 is the primary experimental arm of the study
Double placebo arm of the study
Active control arm of study
Locations(1)
View Full Details on ClinicalTrials.gov
For the most up-to-date information, visit the official listing.
NCT07393334