Anti-CTLA-and anti-PD-1 immune checkpoint inhibitor antibodies impair human sperm motility in-vitro

Ilaria Cosci; Luca De Toni; Paolo Del Fiore; Andrea Di Nisio; Samuela Carraro; Claudia Maria Radu; Loris Bertazza; Simone Mocellin; Jacopo Pigozzo; Giovanna Crivellaro; Marina Coppola; Alberto Ferlin

doi:10.3389/fphar.2025.1534975

Male Fertility · Male Factor Causes

Anti-CTLA-and anti-PD-1 immune checkpoint inhibitor antibodies impair human sperm motility in-vitro

Cosci I, De Toni L, Del Fiore P, Di Nisio A, Carraro S, Radu CM, Bertazza L, Mocellin S, Pigozzo J, Crivellaro G, Coppola M, Ferlin A

Published March 31, 2025 Frontiers in pharmacology

DOI 10.3389/fphar.2025.1534975 PMID 40230698 PMC PMC11994717

RRM Academy Synopsis

Cancer immunotherapy antibodies reduced sperm motility in lab tests

Three cancer immunotherapy antibodies reduced the motility of human sperm in laboratory tests. The tests used sperm from ten men with normal semen and proven fertility. The antibodies were pembrolizumab, nivolumab and ipilimumab. At the highest concentration tested, sperm survival and signs of cell death did not change significantly.

Key Findings

Freshly ejaculated sperm showed PD-1 expression in >99% of cells. CTLA-4 was essentially undetectable.
After 4 hours, exposure to pembrolizumab, nivolumab or ipilimumab was associated with lower progressive sperm motility than untreated controls, and the decrease grew with antibody concentration.
In sperm selected for high motility by swim-up, pembrolizumab and ipilimumab were associated with lower motility at smaller concentrations than nivolumab, which showed an effect only at the highest concentration tested.
At the highest concentration, none of the three antibodies significantly changed the share of apoptotic cells, dead cells or cells with fragmented DNA (all P > 0.05).
Antibodies purified from the medicines, tested at the highest concentration, also lowered motility compared with untreated sperm and unrelated IgG, with no significant change in apoptosis or DNA fragmentation.

Interpretation

The study is a laboratory (in vitro) experiment. Sperm from ten donors with normal semen and proven fertility were incubated with the antibodies for 4 hours. No patient took a drug, men with cancer were not studied, and fertility outcomes were not measured. The authors name the small sample as a major limitation. The effect appears unrelated to sperm expression of each drug's molecular target, in the authors' words. Ipilimumab targets CTLA-4, which sperm did not detectably express, and the authors cannot explain the mechanism. They write that longitudinal studies are needed to examine a possible link with reduced fertility potential.

RRM Context

RRM evaluates both partners, so the man's sperm health is part of the picture. Sperm motility is a standard measure on a semen analysis. The authors say published reports on these drugs and male fertility are sporadic case reports.

Our editorial summary of this paper, not the article's abstract.

Abstract

Background

Immune checkpoint inhibitors (ICIs), namely, anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) monoclonal antibody Ipilimumab and anti- and programmed cell death 1 (PD-1) monoclonal antibodies Nivolumab, and Pembrolizumab, have improved the treatment outcomes for many other cancer types. However, their impact on fertility remains under-explored.

Methods

The possible direct effects of ICIs on human sperm was investigated. Spermatozoa from ten normozoospermic donors were exposed to Ipilimumab, Nivolumab, or Pembrolizumab at concentrations ranging from 1 to 100 ng/mL. Sperm motility was assessed through standard laboratory process. Cell viability and apoptosis markers were evaluated by flow-cytometry using fluorescent Annexin-V probe and Terminal Uridine Nick-End Label (TUNEL) assays. Protein-A-purified therapeutic antibodies (IgG) were also evaluated.

Results

Spermatozoa had high PD-1 (>99%) and negligible CTLA-4 expression. Exposure to ICIs, was associated with a concentration-dependent impairment of sperm motility, noticeable for Pembrolizumab and Ipilimumab since 10 ng/mL, and for Nivolumab since 100 ng/mL. However, no significant effect on cell apoptosis or viability was shown. Purified IgG from ICIs maintained the adverse effect on cell motility without affecting viability.

Conclusion

ICIs, specifically Pembrolizumab, Nivolumab, and Ipilimumab, adversely affect human sperm motility in vitro. Further research is required to understand the underlying mechanisms and clinical implications.

Topics

Male Fertility › Male Factor Causes › Lifestyle and Environment · Therapeutics › Prescribing Safety › Medication Safety in Pregnancy

Ilaria Cosci, Luca De Toni, Paolo Del Fiore, Andrea Di Nisio, Samuela Carraro, Claudia Maria Radu, Loris Bertazza, Simone Mocellin, Jacopo Pigozzo, Giovanna Crivellaro, Marina Coppola, Alberto Ferlin

I Cosci, L Toni, P Fiore, A Nisio, S Carraro, C Radu, L Bertazza, S Mocellin, J Pigozzo, G Crivellaro, M Coppola, A Ferlin

PMID 40230698 40230698 DOI 10.3389/fphar.2025.1534975 10.3389/fphar.2025.1534975 Cosci et al. 2025, Cosci 2025

Anti-CTLA-and anti-PD-1 immune checkpoint inhibitor antibodies impair human sperm motility in-vitro

Cancer immunotherapy antibodies reduced sperm motility in lab tests

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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