A Phase 1 interventional study of DITEST and Testosterone undecanoate in Male Hypogonadism, sponsored by Neurocrine UK Limited. Completed at 1 site in United Kingdom. Open to male participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-14.
Sponsored by Neurocrine UK Limited (formerly part of Neurocrine Biosciences) · Phase 1, Interventional, and Treatment
DITEST is an oral formulation of native testosterone for the treatment of androgen deficiency in men. The study was a Phase 1 clinical study in hypogonadal men, defined according to FDA and Endocrine Society Guidelines, designed to evaluate the pharmacokinetic (PK) characteristics of DITEST, and to assess the safety and tolerability of DITEST in the target population.
There is an unmet need for a native oral testosterone therapy for men with androgen (testosterone) deficiency. Ideally such a treatment should have reproducible PK, does not need to be taken with fatty meals, can be taken once or twice daily, and provides physiological exposure to testosterone. This Phase 1, randomised, open-label, 2-cohort, cross-over study was therefore designed to evaluate the PK characteristics of DITEST in both the fed and fasted states according to FDA guidelines, and to assess the safety and tolerability of DITEST in the target population.
The study was conducted in male subjects from 18 to 80 years of age requiring testosterone replacement therapy for primary or secondary hypogonadism. The study was a randomised, active control, single dose, 2-way cross-over study in 2 cohorts. In each cohort subjects who meet the entry criteria at screening and baseline were randomised to one of 2 sequences:
Cohort 1: single dose of 120 mg (3 x 40 mg) DITEST followed by a single dose of 80 mg (2 x 40 mg) testosterone undecanoate (TU) or a single dose of 80 mg TU followed by single dose of 120 mg DITEST. The two treatments were separated by a minimum of a 7-day washout period, with both treatments given in the fed state.
Cohort 2: single dose of 200 mg (5 x 40 mg) DITEST (fed) followed by a single dose of 200 mg DITEST (fasted) or a single dose of 200 mg DITEST (fasted) followed by single dose of 200 mg DITEST (fed). The two treatments were separated by a minimum of a 7-day washout period.
13 subjects were recruited into cohort 1 and 12 subjects were recruited into cohort 2, resulting in a total of 25 subjects being administered study medication in this study. Subjects were not recruited into Cohort 2 until the results of subjects treated in Cohort 1 had been evaluated (this review was to determine if the intended dose for Cohort 2 needed to be adjusted). No other testosterone treatments were allowed for the duration of the study (including the washout periods).
Each subject was required to attend the study centre for a minimum of either 4 or 5 visits: a screening assessment, an evaluation of baseline testosterone levels after the washout period from the subject's current medication (only for subjects currently on testosterone replacement therapy), both dosing days, and a follow-up visit at the end of the study.
75 studies on the registry are indexed under Eunuchism; 21 are open to participants now.
This study's enrollment of 25 is below the median of 60 across 55 interventional studies indexed under Eunuchism.
Browse Eunuchism studies →Neurocrine UK Limited is the lead sponsor of 18 studies on the registry; none are open to participants now.
First submitted before Neurocrine UK Limited left Neurocrine Biosciences.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cohort 1: single dose of 120 mg (3 x 40 mg) DITEST followed by a single dose of 80 mg (2 x 40 mg) testosterone undecanoate or a single dose of 80 mg (2 x 40 mg) testosterone undecanoate followed by single dose of 120 mg (3 x 40 mg) DITEST. The two treatments are separated by a minimum of a 7-day washout period, with both treatments given in the fed state.
Drug: DITEST · Drug: Testosterone undecanoate
Cohort 2: single dose of 200 mg (5 x 40 mg) DITEST (fed) followed by a single dose of 200 mg DITEST (fasted) or a single dose of 200 mg DITEST (fasted) followed by single dose of 200 mg (5 x 40 mg) DITEST (fed). The two treatments are separated by a minimum of a 7-day washout period.
Drug: DITEST
Lipid formulation of native oral testosterone.
Generic treatment for patients with primary or secondary male hypogonadism
Testosterone serum concentrations - Peak Plasma Concentration (Cmax)
Testosterone serum concentrations after administration of a single dose of 120mg or 200mg DITEST and 80mg testosterone undecanoate in the fed state, as measured by the primary PK parameter of Cmax.
Time frame: Study day 0 to Study Day >7 (sampling time points at -0.5, 0.25 [120mg and TU arms only], 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8 and 10 hours post-Investigational Medicinal Product (IMP) administration, on each visit date)
Testosterone serum concentrations - Area under the serum testosterone concentration-time curve from time 0-10 (AUC(0-10))
Testosterone serum concentrations after administration of a single dose of 120mg or 200mg DITEST and 80mg testosterone undecanoate in the fed state, as measured by the primary PK parameter of AUC.
Time frame: Study day 0 to Study Day >7 (sampling time points at -0.5, 0.25 [120mg and TU arms only], 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8 and 10 hours post-IMP administration, on each visit date)
Testosterone serum concentrations - Peak serum testosterone Concentration (Cmax)
Testosterone serum concentrations after 200mg dose of DITEST in the fed and fasted states, as measured by the primary PK parameter of Cmax.
Time frame: Study day 0 to Study Day >7 (sampling time points at -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8 and 10 hours post-IMP administration, on each visit date)
Testosterone serum concentrations after 200mg dose - Area under the serum testosterone concentration-time curve (AUC 0-10)
Testosterone serum concentrations after 200mg dose of DITEST in the fed and fasted states, as measured by the primary PK parameter of AUC (0-10)
Time frame: Study day 0 to Study Day >7 (sampling time points at -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8 and 10 hours post-IMP administration, on each visit date)
Adverse events
Adverse events (AEs) observed throughout the study.
Time frame: Through study completion - a maximum of 84 days.
Vital signs
Observed changes in vital signs data during the course of the study.
Time frame: Through study completion - a maximum of 84 days.
Electrocardiogram (ECG)
Observed changes in ECG data during the course of the study.
Time frame: Through study completion - a maximum of 84 days.
Safety Laboratory Data
Observed changes in Safety Laboratory data during the course of the study.
Time frame: Through study completion - a maximum of 84 days.
Plan to share: No
No publications or documents are linked to this record.
Ran from Nov 2016 to primary completion in Oct 2018, 23 months.
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This study is completed, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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