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

NCT07393334 | Recruiting Phase 2 FDA Drug

• 1 other identifier: NLS-133-CLIN001
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Male Contraception; Semen Volume; Sperm Motility

Keywords

Effect of NLS-133 on semen volume and semen parameters

Outcome Measures

Primary Outcomes (2)

• Semen volume (mL)

  90 and 180 minutes for each treatment cycle

• Sperm count (millions/mL)

  Measurement of sperm count

  90 and 180 minutes for each treatment cycle

Secondary Outcomes (1)

• Sperm motility

  90 and 180 after placebo, active-control or NLS-133 administration

Study Arms (3)

Placebo

PLACEBO COMPARATOR

Drug: Placebo

Active Control

ACTIVE COMPARATOR

generic alpha-1-adrenergic receptor antagonist

Drug: Active Comparator #1

NLS-133 (combination of two FDA-approved drugs)

EXPERIMENTAL

Drug: NLS-133

Interventions

NLS-133 DRUG

NLS-133 is the primary experimental arm of the study

NLS-133 (combination of two FDA-approved drugs)

Placebo DRUG

Double placebo arm of the study

Placebo

Active Comparator #1 DRUG

Active control arm of study

Also known as: Active control

Active Control

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Next Life Sciences: lead

Study Sites (1)

Population Center for Research in Human Reproduction and Departments of Medicine, University of Washington

Seattle, Washington, 98195, United States

RECRUITING

Central Study Contacts

John K Amory, MD, MPH, MSc

CONTACT

(206) 616-1727; jamory@uw.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Randomized, placebo- and active-controlled, cross-over design

Study Record Dates

• First Submitted: December 31, 2025
• First Posted: February 6, 2026
• Study Start: December 2, 2025
• Primary Completion: March 1, 2026
• Study Completion: May 1, 2026
• Last Updated: February 6, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)