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Low-dose isotretinoin compared with drug combination for treating acne in adult women: a two‑step randomized trial

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on acne in adult women, a common skin condition that causes pimples, blackheads, and sometimes deeper nodules. Two oral medicines are being examined: the vitamin‑A‑derived drug isotretinoin given at a low dose, and the hormone‑blocking drug spironolactone. In the later part of the trial, standard skin creams that contain tretinoin, benzoyl peroxide, or adapalene may be used as comparison.

The purpose of the study is to determine whether the low‑dose oral medication works better than the hormone‑blocking drug for quickly clearing the skin and improving quality of life, and whether the hormone‑blocking drug is more effective than usual creams for keeping the skin clear over time. During the first few months, participants receive either the low‑dose oral medication or the hormone‑blocking drug as an intensive “attack” treatment aimed at rapid improvement. After skin clears, participants are either continued on the hormone‑blocking drug or switched to the usual topical creams for a “maintenance” period intended to prevent new break‑outs.

Participants attend regular visits for safety checks and skin assessments over a period of about six months. The study records any changes in the number and type of lesions and asks participants about how their skin condition affects daily life.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline Visit and Enrollment

    You attend a first visit where you give informed consent and provide information about your health history.

    The study team measures the severity of your acne using the Global Evaluation Assessment (GEA) score, which rates acne from 0 (no acne) to 5 (most severe).

  2. Step 2

    Randomization to Attack Phase Treatment

    You are randomly assigned to receive one of two oral medications for the attack phase:

    Isotretinoin low‑dose, taken orally at a dose of 0.25 mg per kilogram of body weight each day, or

    Spironolactone taken orally at a dose of 75 mg each day.

    Isotretinoin is a vitamin A‑derived drug that reduces oil production and inflammation. Spironolactone is a medication that blocks certain hormones that can worsen acne.

  3. Step 3

    Attack Phase Treatment Period

    You continue the assigned medication daily for up to six months.

    During this period you attend regular follow‑up visits, typically once a month, so the study team can check your acne severity, monitor side effects, and adjust care if needed.

  4. Step 4

    Mid‑Study Assessment at Month 6

    At the six‑month visit the GEA score is measured again to determine whether the acne has improved sufficiently.

    If the acne is judged to be under control, you move on to the maintenance phase of the trial.

  5. Step 5

    Randomization to Maintenance Phase Treatment

    Based on the medication you received in the attack phase, you are assigned a maintenance regimen:

    If you received isotretinoin in the attack phase, you now take spironolactone at a higher dose of 150 mg taken orally each day.

    If you received spironolactone in the attack phase, you continue with standard topical care, which may include one of the following applied to the skin as directed:

    - Tretinoin (a topical vitamin A derivative),

    - Benzoyl peroxide (a topical antibacterial agent), or

    - Adapalene (a topical retinoid).

    The topical products are usually applied once daily to the affected areas.

  6. Step 6

    Maintenance Phase Treatment Period

    You continue the maintenance medication daily for the remainder of the study, which may extend up to twelve months from the start of the trial.

    Periodic visits are scheduled (often every two to three months) to evaluate acne control and ensure the medication is well tolerated.

  7. Step 7

    Final Study Visit and End of Trial

    At the final visit the study team records the GEA score and any other relevant outcomes to complete the trial data.

    You receive a summary of the study results and any recommendations for ongoing acne care.

Who can join the trial?

8 criteria

  • Woman who is at least 25 years old.
  • Facial acne (either on the jawline area called mandibular or spread out over the face, known as diffuse) that has been present for at least six months.
  • Has already taken a type of antibiotic called cyclines for at least three months within the past two years.
  • Has acne that did not improve or returned after using cyclines, or had a bad side effect (called an adverse reaction) while taking them.
  • Has acne that is classified as mild, moderate, or severe according to a scoring system (GEA score 2, 3, or 4).
  • Is using a reliable method of birth control (effective contraception) for at least one month.
  • Can understand the study information and is willing to sign an Informed Consent form.
  • Is covered by the French national health insurance system (French social coverage).

Who cannot join the trial?

18 criteria

  • If you have a GEA score (a number that shows how severe your acne is) of 1 or 5, you cannot join the study.
  • If you have taken oral isotretinoin (a strong acne medication) at any time during the past 12 months, you are excluded.
  • If you have used systemic antibiotics for acne (antibiotics taken by mouth) in the past 3 months, you cannot participate.
  • If you have taken anti‑androgen medicines (drugs that block male hormones) in the past 6 months, you are excluded, unless they were part of certain birth‑control pills.
  • If you are known to be intolerant or allergic to spironolactone, you cannot join.
  • If you have severe or acute kidney problems (known as renal insufficiency), you are excluded.
  • If your estimated glomerular filtration rate (eGFR, a test of kidney function) is below 60 ml/min/1.73 m², you cannot participate.
  • If you have high potassium levels (hyperkalaemia) or need potassium‑sparing diuretics (medicines that keep potassium in the body) such as amiloride, canrenoate, eplerenone, or triamterene, you are excluded.
  • If you are continuously taking medicines like ACE inhibitors, angiotensin II blockers, non‑steroidal anti‑inflammatory drugs (NSAIDs), heparin, low‑molecular‑weight heparin, ciclosporin, tacrolimus, or trimethoprim, you cannot join.
  • If you take potassium salts (supplements containing potassium), you are excluded.
  • If you are using the medicine mitotane, you cannot participate.
  • If you have an androgen‑secreting adrenal or ovarian tumor, Cushing’s syndrome, congenital adrenal hyperplasia, Addison’s disease, or end‑stage liver disease, you are excluded.
  • If you are known to be intolerant or allergic to oral isotretinoin, you cannot join.
  • If you are pregnant or breastfeeding, you are excluded.
  • If you have impaired liver function (the liver is not working well), you cannot participate.
  • If you have high blood lipid levels (high cholesterol or triglycerides), you are excluded.
  • If you have too much vitamin A in your body (hypervitaminosis A) or are taking vitamin A supplements, you cannot join.
  • If you are currently taking tetracyclines (a class of antibiotics), you are excluded.
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Investigated drugs

  • Spironolactone

    is an oral pill that works by blocking certain hormones that can increase oil production in the skin. In this study it is given during the first “attack” phase to see how well it clears acne, and later it is used in the maintenance phase to help keep the skin clear, compared with standard topical creams.

  • Isotretinoin

    is an oral medication taken at a low dose based on a person’s weight. It reduces the activity of oil glands and lowers skin inflammation. In the trial it is the test drug used in the attack phase, and researchers are checking if it improves acne severity and quality of life better than spironolactone.

  • Tretinoin

    is a cream or gel applied to the skin that speeds up skin cell turnover, helping to prevent clogged pores. In this study it is used as a comparator topical treatment during the maintenance phase to see how it works against spironolactone.

  • Benzoyl peroxide

    is a topical gel or cream that kills the bacteria that cause acne and helps unclog pores. It is included in the trial as a comparator topical therapy used in the maintenance phase.

  • Adapalene

    is a topical retinoid cream that encourages normal skin cell growth and reduces inflammation. It serves as another comparator topical treatment during the maintenance phase of the study.

What is already known about the treatment

  • Spironolactone

    This medication is taken as an oral tablet and works by blocking the hormone aldosterone and also weakly blocking male hormones, which helps reduce water retention and skin oiliness. It is a well‑studied drug that is approved for high blood pressure, heart failure, and hormonal acne in adult women. At the molecular level it binds to aldosterone receptors in the kidney, preventing sodium reabsorption, and it interferes with androgen receptors on skin cells. It belongs to the class of steroidal antimineralocorticoids and is also considered an anti‑androgen.

  • Isotretinoin

    Isotretinoin is taken as an oral capsule and is used in low doses to treat severe acne by decreasing oil gland activity and normalizing skin cell shedding. It is an established, prescription‑only drug with extensive research supporting its effectiveness for acne and some other skin disorders. The drug works by binding to retinoic acid receptors inside cells, changing gene activity that lowers sebum production and reduces inflammation. It is classified as a systemic retinoid, a vitamin A‑derived medication.

  • Tretinoin

    Tretinoin is applied to the skin as a cream or gel and is used to treat acne and signs of photo‑aged skin. It is an approved, prescription topical medication that has been widely studied for its skin‑renewing effects. It works by attaching to retinoic acid receptors in skin cells, speeding up cell turnover and preventing pores from becoming clogged. Tretinoin belongs to the class of topical retinoids.

  • Benzoyl Peroxide

    This drug is applied to the skin as a gel, cream, or wash and is commonly used to clear mild to moderate acne. It is an over‑the‑counter topical agent with a long history of safe use in acne care. Benzoyl peroxide releases oxygen that kills acne‑causing bacteria and also helps to loosen dead skin cells in the pores. It is classified as a topical oxidizing and antibacterial agent.

  • Adapalene

    Adapalene is a cream or gel applied to the skin and is indicated for the treatment of acne. It is a prescription‑only topical retinoid that has been well documented in clinical studies for its effectiveness and safety. The medication binds selectively to retinoic acid receptors, promoting normal skin cell growth and reducing inflammation. It belongs to the class of synthetic topical retinoids.

Investigated diseases

Adult female acne - Adult female acne is a common skin condition characterized by comedones, papules, pustules, and sometimes nodules, primarily on the face, chest, and back. It often begins after age 25 and may be linked to hormonal fluctuations. Lesions may start as occasional breakouts and can become more persistent over months. In some women, the condition can wax and wane, with periods of worsening. The disease may spread to involve more areas if not controlled. The severity can increase from mild to moderate to severe as lesions multiply and inflammation persists.
Trial detailsLast updated 28 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-520773-39-00Protocol codeAPHP240918/AFTEREstimated enrolment300 patientsSponsorAssistance Publique Hopitaux De Paris

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