FDA Approves Gwyn Lo, a Once Weekly Low-Dose Estrogen Contraceptive Patch

The FDA approved Gwyn Lo (norelgestromin and ethinyl estradiol transdermal system), a new once-weekly combined hormonal contraceptive (CHC) patch delivering a low dose of estrogen. The approval was granted under the FDA's 505(b)(2) regulatory pathway and was supported by results from the phase 3 LUMINOUS Study (NCT05139121), which evaluated contraceptive efficacy, safety, and patch adhesion.^1,2

Gwyn Lo delivers norelgestromin 220 mcg/day and ethinyl estradiol 20 mcg/day and is indicated for women of childbearing potential with a body mass index (BMI) below 30 kg/m² who are appropriate candidates for CHCs.¹

"Gwyn Lo will provide a discreet option for women seeking a reversible, noninvasive, once-weekly contraception patch with a low dose of estrogen," Philippe Martin, chief R&D officer of Viatris, said in a news release.¹ "Building on our expertise in transdermal drug delivery systems and legacy in women's health, we are pleased that the approved label for this new patch reflects the strength of our clinical program.”

Martin noted that the label includes efficacy data in women with a BMI of 25 to less than 30 kg/m², with no BMI-based limitation of use in that population.¹

Trial Data Behind the Approval

The LUMINOUS Study was a Phase 3, multicenter, open-label, single-arm trial (NCT05139121) sponsored by Mylan Technologies Inc, a Viatris company, and investigated at sites including Columbia University Irving Medical Center.²

The primary efficacy end point was the Pearl Index—the number of pregnancies per 100 woman-years of exposure—which was 4.14 (95% CI, 2.77-5.95) in the efficacy-evaluable population of women aged 18 to 35 years.¹

Only 1.3% of the 39,790 transdermal systems applied during the year-long trial fully detached. Cycle control improved over time, with rates and duration of unscheduled bleeding or spotting decreasing from 34.5% and a mean of 3.2 days in cycle 1 to 20.0% and 2.4 days by cycle 13.¹

Separately, four phase 1 studies evaluating various application sites and conditions—including sauna use, whirlpool exposure, treadmill exercise, and cold-water bathing—demonstrated consistent drug delivery.¹

The most common adverse reactions reported in 2% or more of participants were application site irritation (4.8%), application site erythema (3.7%), application site pruritus (3.7%), intercycle bleeding (3.9%), heavy withdrawal bleeding (2.0%), and nausea (2.0%).¹

What This Means for Pharmacists

New contraceptive options such as Gwyn Lo arrive as pharmacists are taking on a larger role in contraceptive access nationally. Many states have expanded scope-of-practice laws to allow pharmacists to prescribe hormonal contraceptives, including birth control pills, patches, rings, or injections, as one strategy to increase access.³

States determine this scope of practice through their own laws and regulations, typically delegating oversight to a state board of pharmacy or health department, and pharmacist prescribing may improve medication adherence by reducing the barriers that can lead to a lapse in contraceptive use. The Centers for Medicare & Medicaid Services has also issued guidance outlining state options to expand pharmacists' scope of practice to improve Medicaid beneficiaries' access to medications, including contraceptives.³

Common barriers patients face in accessing contraceptives include transportation, childcare, and work-schedule conflicts—barriers a pharmacy-based prescribing model is designed to help address.³

That expanded scope brings counseling responsibilities that research suggests are not yet fully supported. A survey of Australian community pharmacists published in BMJ Sexual and Reproductive Health found that 85% agreed contraceptive counseling fits within their current professional activities, and 80% cited improved access to contraceptive decision support as a key motivator for providing it.⁴

However, researchers identified lack of assistance tools, lack of training opportunities, and lack of payment mechanisms as significant barriers and noted that pharmacists rated their knowledge highest for combined oral contraceptives and lowest for copper intrauterine devices. The study's authors also pointed to similar findings in the United States, where "most pharmacists described contraceptive education in the pharmacy curricula as being inadequate to prepare them for contraception prescribing."⁴

Safety Considerations and Availability

Gwyn Lo carries contraindications for women who smoke and are older than 35 years, due to an increased risk of serious cardiovascular events, and for women with a BMI of 30 kg/m² or higher. The risk of venous thromboembolism may be greater with Gwyn Lo in women with a BMI above 30 kg/m² compared with women with a lower BMI. Patients should discuss their medical history and risk factors with their health care provider before using the patch.¹

The patch is applied once weekly for 3 consecutive weeks, followed by 1 patch-free week. Viatris said it expects Gwyn Lo to be commercially available later this year and will share additional details during its upcoming financial results call.¹

REFERENCES

1. Viatris Inc. Viatris receives U.S. FDA approval for Gwyn Lo, a once-weekly contraceptive patch. News release. Viatris Inc. July 29, 2026. Accessed July 29, 2026. https://newsroom.viatris.com/2026-07-29-Viatris-Receives-U-S-FDA-Approval-for-Gwyn-Lo-TM-,-a-Once-Weekly-Contraceptive-Patch

2. Columbia University Irving Medical Center. LUMINOUS Study: effectiveness of contraceptive patch (MR-100A-01) in preventing pregnancy. RecruitMe. Accessed July 29, 2026. https://recruit.cumc.columbia.edu/studyinfopage/2439

3. Staren D. State approaches to pharmacist prescribing of hormonal contraceptives. National Academy for State Health Policy. October 28, 2024. Accessed July 29, 2026. https://nashp.org/state-approaches-to-pharmacist-prescribing-of-hormonal-contraceptives/

4. Fyfe S. Pharmacy's role in contraceptive counseling and care. Contemporary OB/GYN. January 20, 2023. Accessed July 29, 2026. https://www.contemporaryobgyn.net/view/pharmacy-s-role-in-contraceptive-counseling-and-care