New gel could boost fertility for couples struggling to conceive
NCT ID NCT07669584
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tests a gel called PKB171, which contains a drug used to improve blood flow and sperm movement. Couples with mild male infertility who have been trying to conceive for 6 to 24 months apply the gel after sex. The goal is to see if it increases pregnancy rates compared to a placebo gel. The trial involves 732 couples across multiple centers.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- pentoxifylline gel (PKB171)
- What this could lead to
- If it works, this gel could offer a simple, at-home option to improve pregnancy rates for couples with mild male factor infertility.
- What could go wrong
- This is an early combined phase 2/3 trial. A prior phase 2 was stopped early due to recruitment issues, and the main side effects include local irritation. Success is not guaranteed.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2/3
Runs two stages together: whether the treatment works, then large-scale confirmation.
- Participants
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About 732 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Oct 2025
- Expected to finish
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Oct 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 38 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Subjects eligible for inclusion in this study must meet all the following criteria: 1. Written informed consent form signed before any study test or procedure. 2. Unable to conceive for more than 6 months and less than 24 months, despite regular and adequate unprotected sexual intercourse. 3. Willing and able to comply with the protocol. 4. Female subjects with the following criteria: * Age ≥ 18 and ≤ 38 years. * Regular spontaneous menstrual cycles with a 25- to 35-day length (intercycle variation less than 5 days) within the last six cycles before the first visit. * Normal uterine cavity shown on transvaginal sonography. * Normal ovarian reserve, demonstrated by AMH ≥ 1 ng/ml at day 2-5 of the cycle. * Antral follicle count (sum of both ovaries) ≥ 6 5. Male subjects with the following criteria: * Age ≥ 18 and ≤ 50 years. * Spermiogram with semen volume ≥ 1mL, concentration \> 11 M/mL, \< 42% total mobility and normal forms ≥ 2% Exclusion Criteria: Subjects eligible for this study, both women and men, must not meet any of the following criteria: 1. Body mass Index (BMI) \< 18 and ≥ 32 kg/m². 2. Any sexual intercourse with another partner (other than corresponding trial subject) within 12 weeks entry in the study and during it. 3. Couples who had any previous assisted reproductive technology (ART) cycle (in vitro fertilization, IVF, or intracytoplasmic sperm injection, ICSI) before inclusion into the trial. 4. Active hepatitis B, C, HIV, genital herpes, Chlamydia, Gonorrhea or Syphilis infection. 5. History of malignant disease (cancer). Previous or planned chemotherapy or radiotherapy. 6. History of cerebral or retinal hemorrhage, acute myocardial infarction. 7. In females: Prohibited concomitant intravaginal products or procedures. 8. Hypersensitivity or intolerance to pentoxifylline, xanthine derivatives or any of the excipients of the IMP. 9. Employees of the investigator or trial center, with direct involvement in the proposed trial or other studies under the direction of that investigator or trial center, as well as family members of the employees or the principal investigator. 10. People committed to an institution by virtue of an order issued either by the judicial or other authorities. 11. Reasonable expectation that the subject will not be able to satisfactorily complete the study: * History of current psychiatric illness that would interfere with the subject's ability to comply with protocol requirements or give informed consent. * History of alcohol or drug abuse that would interfere with the subject's ability to comply with protocol requirements. * Receipt of any investigational drug within three months of screening visit. * Previous enrolment in this trial. * Documented noncompliance. * Any other condition of the subject that in the opinion of the investigator may compromise evaluation of the trial treatment or may jeopardize subject's safety or compliance to protocol requirements. 12. Patients with peptic ulcers or recent history thereof. 13. Patients with haemorrhage (e.g. extensive retinal bleeding) or at risk of increased bleeding 14. Patients with severe coronary artery disease, when in the physician's judgement myocardial stimulation might prove harmful. 15. Patients with severe hepatic and renal impairment. 16. Patients without adequate laboratory parameters according to the normal ranges of local laboratory. 17. Female risk factors of infertility defined by any of the following: * Absence of any or both ovaries. * Abnormal uterine cavity assessed by transvaginal sonography. Specially, submucosal fibroids, intramural fibroids affecting the uterine cavity (any size), more than 5 intramural fibroids ≥ 4 cm in diameter, or more than 6 intramural fibroids of any size. Women with any subserosal fibroid ≥ 8cm will also be excluded. * Risk factors for fallopian tube obstruction as abdominal surgery, diseases such as endometriosis, tuberculosis, ruptured appendix or peritonitis, Pelvic Inflammatory Disease (PID), Chlamydia and gonorrhea. * Antecedents of long-term amenorrhea, polycystic ovarian syndrome, type III or IV endometriosis, or fallopian tube obstruction. * Previous gynecological surgery, excluding caesarean section or myomectomy within predefined limits. * For women, prohibited concomitant therapies within 28 days before enrolled into the study until last treatment visit: sex hormones, selective estrogen receptor modulators, aromatase inhibitors or oral pentoxifylline. * Two or more clinical or preclinical spontaneous miscarriages. * Lactation or pregnancy. * Known abnormal karyotype 18. Male risk factors of infertility defined by any of the following: * Vasectomy * Known genetic abnormalities related to infertility: i.Endocrine or systemic disorders causing hypergonadotropic hypogonadism (either, congenital or acquired). ii.Known abnormal karyotype * Previously diagnosed varicocele * The use of certain drugs (e.g., anabolic steroids, antineoplastic agents, erythromycin, tetracycline, gentamycin). * Viral process with fever ≥ 38ºC in the past 70 days
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
12 sites. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Assir Dreta-Cap Pare Claret
NOT_YET_RECRUITINGBarcelona, 08037, Spain
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Assir Dreta-Cap Roger de Flor
NOT_YET_RECRUITINGBarcelona, 08037, Spain
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Clinica Fertty
NOT_YET_RECRUITINGBarcelona, 08010, Spain
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Clinica Sagrada Familia
RECRUITINGBarcelona, 08022, Spain
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Clinica Universidad de Navarra
RECRUITINGPamplona, Navarre, 31008, Spain
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Clinica Universidad de Navarra
RECRUITINGMadrid, 28027, Spain
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HM Gabinete Médico Velázquez
NOT_YET_RECRUITINGMadrid, 28001, Spain
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Hospital Universitario L Paz
NOT_YET_RECRUITINGMadrid, 28046, Spain
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Hospital Universitario Nuestra Señora de Valme
RECRUITINGSeville, 41014, Spain
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Hospital Universitario San Rafael
RECRUITINGMadrid, 28016, Spain
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Hospital de la Santa Creu i Sant Pau
NOT_YET_RECRUITINGBarcelona, 08041, Spain
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Hospital del Mar
RECRUITINGBarcelona, 08003, Spain
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