Effects of NLS-133, a Potential Non-Hormonal "On-Demand" Male Contraceptive

Conditions

• Male Contraception
• Semen Volume
• Sperm Motility

Eligibility Criteria

Sex

MALE

Age

18 Years - 55 Years

Healthy Volunteers

Accepted

Interventions

• NLS-133 — DRUG
  NLS-133 is the primary experimental arm of the study
• Placebo — DRUG
  Double placebo arm of the study
• Active Comparator #1 — DRUG
  Active control arm of study

Study Details

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.

Key Dates

Start date

Dec 2, 2025

Status verified

Jan 2026

Primary completion

Mar 31, 2026

Completion

May 31, 2026

Study Design

Enrollment

10 participants (estimated)

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

TREATMENT

Arms

• Placebo Comparator: Placebo
• Active Comparator: Active Control
  generic alpha-1-adrenergic receptor antagonist
• Experimental: NLS-133 (combination of two FDA-approved drugs)

Primary Outcome Measure

Semen volume (mL) [ Time Frame: 90 and 180 minutes for each treatment cycle ]

Central Contacts

• John K Amory, MD, MPH, MSc
  (206) 616-1727
  [email protected]

Locations (1)

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