A Phase 4 interventional study of Twirla® (Levonorgestrel/Ethinyl Estradiol) Transdermal System in Residual Drug Amount of EE and LNG, sponsored by Insud Pharma. Completed at 1 site in United States. Open to female participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Insud Pharma · Phase 4, Interventional, and Other
The objective of this open-label study was to assess residual EE and LNG content on used Twirla® TDSs, packaging, and the skin surface at the application site after 7 full days of wear and the estimate EE and LNG loaded on control TDSs using valid analytical methods.
Twirla® (levonorgestrel and ethinyl estradiol) transdermal system is an FDA-approved transdermal delivery system (TDS) indicated as a method of contraception for use in women of reproductive potential with a body mass index (BMI) \< 30 kg/m² for whom a combined hormonal contraceptive is appropriate. The 28-day TDS regimen is worn for 7 days for 3 consecutive weeks, followed by a 7-day TDS-free period.
Study ATI-CL28 measured residual EE and LNG content on Twirla® packaging (including storage pouches and release liners), Twirla® TDSs worn for 7 full days, and application site stratum corneum (SC) per Postmarketing Commitment 3785-2. Validated analytical methods were used in this study to measure residual EE and LNG.
Insud Pharma is the lead sponsor of 10 studies on the registry; 2 are open to participants now.
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:
Has a to combined estrogen-progestin contraceptive use (as defined by a category 3 or 4 condition of the 2016 U.S. Medical Eligibility Criteria for Contraceptive Use), including:
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.
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.
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
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.
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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants applied a single Twirla® transdermal system and wore it continuously for 7 days. After patch removal, residual levonorgestrel and ethinyl estradiol content was measured in the used transdermal system, packaging components, and application-site stratum corneum.
Drug: Twirla® (Levonorgestrel/Ethinyl Estradiol) Transdermal System
Twirla® is a transdermal delivery system that delivers levonorgestrel and ethinyl estradiol. In this study, participants applied a single transdermal system and wore it continuously for 7 days.
The Sum of Means for EE and LNG Content on Used TDSs, Storage Pouches, Release Liners, and Skin Swabs
Measurements of Residual Ethinyl Estradiol and Levonorgestrel (μg) Per Protocol Population Post 7-Day Wear
Time frame: 7 days
The Sum and Means for EE and LNG Content on Control TDSs, Storage Pouches, and Release Liners
Measurements of Ethinyl Estradiol and Levonorgestrel (μg) in Controls
Time frame: 7 days
| Milestone | Twirla® Transdermal System |
|---|---|
| Started | 28 |
| Completed | 26 |
| Not completed | 2 |
| Withdrew: Withdrawal by subject | 1 |
| Withdrew: Protocol deviation | 1 |
Measurements of Residual Ethinyl Estradiol and Levonorgestrel (μg) Per Protocol Population Post 7-Day Wear
| (μg) | Twirla® Transdermal System |
|---|---|
| Ethinyl Estradiol (μg) | 2028.7 ± 43.01 |
| Levonorgestrel (μg) | 2189.6 ± 62.35 |
Measurements of Ethinyl Estradiol and Levonorgestrel (μg) in Controls
| (μg) | Controls to Assess Drug Loaded for EE and LNG |
|---|---|
| Ethinyl Estradiol (μg) | 2102.0 ± 85.26 |
| Levonorgestrel (μg) | 2454.0 ± 93.70 |
Collected over Adverse events were monitored from the time of written informed consent to 7 days following TDS removal. Non-serious events are listed at a 1% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Twirla® Transdermal System | 0/28 (0%) | 0/28 (0%) | 9/28 (32.1%) |
| Event | Twirla® Transdermal System |
|---|---|
| Mild treatment emergent adverse events (TEAEs)General disorders | 8/28 |
| Moderate treatment emergent adverse events (TEAEs)Nervous system disorders | 1/28 |
Per Protocol Population
| Age, Continuous(Age (years)) | Twirla® Transdermal System |
|---|---|
| Mean | 28.3 ± 4.62 |
| Age, Continuous(Age (years)) | Twirla® Transdermal System |
|---|---|
| Median | 29.5 (20 to 36) |
| Sex: Female, Male(Participants) | Twirla® Transdermal System |
|---|---|
| Female | 26 |
| Male | 0 |
| Race (NIH/OMB)(Participants) | Twirla® Transdermal System |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 3 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 18 |
| White | 5 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Ethnicity (NIH/OMB)(Participants) | Twirla® Transdermal System |
|---|---|
| Hispanic or Latino | 6 |
| Not Hispanic or Latino | 20 |
| Unknown or Not Reported | 0 |
| Weight (kg), Mean(kg) | Twirla® Transdermal System |
|---|---|
| Mean | 66.9 ± 7.68 |
| Weight (kg), Median(kg) | Twirla® Transdermal System |
|---|---|
| Median | 67.1 (50 to 84.1) |
| Height (cm), Mean(cm) | Twirla® Transdermal System |
|---|---|
| Mean | 161.8 ± 6.53 |
3 further baseline measures are reported on the registry.
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Oct 2021 to primary completion in Nov 2021, 0 months.
Results were first posted in Aug 2026, 4 years 9 months after primary completion.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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