Inclusion Criteria:

• Ability to comprehend and willingness to sign a written ICF for the study.
• Male or female aged 18 years or older.
• Clinical diagnosis of LP with predominant cutaneous involvement.
• IGA score of 3 or 4 at screening and baseline.
• LP affecting ≤ 20% of the BSA at screening and baseline.
• Baseline LP-related Itch NRS score ≥ 4. Baseline Itch NRS is defined as the 7-day average of Itch NRS score before Day 1 (data from a minimum of 4 out of 7 days directly prior to Day 1 is needed).
• Willingness to avoid pregnancy or fathering children based on the criteria below:
  • Male participants with reproductive potential must agree to take appropriate precautions to avoid fathering children from screening through 90 days (a spermatogenesis cycle) after the last application of study treatment and must refrain from donating sperm during this period. Permitted methods in preventing pregnancy (see Appendix A) should be communicated to the participants and their understanding confirmed;
  • Female participants who are WOCBP must have a negative serum pregnancy test at screening and before the first application on Day 1 and must agree to take appropriate precautions to avoid pregnancy from screening through 30 days (1 menstrual cycle) after the last application of study treatment and must refrain from donating oocytes during this period. Permitted methods in preventing pregnancy should be communicated to the participants and their understanding confirmed;
  • A female participant not considered to be of childbearing potential.

Exclusion Criteria:

• Concurrent conditions and history of other diseases:
  • Variants of LP deemed by the investigators to be inappropriate for topical treatment, including but not limited to predominant mucosal (such as oral or vaginal) LP:
    • Note: Participants with mucosal LP can be eligible if they have predominant cutaneous LP and agree to not treat mucosal LP during the study.
  • Active ongoing inflammatory diseases of the skin other than LP that might confound the evaluation of LP lesions or compromise participant safety;
  • Any other concomitant skin disorder (eg, generalized erythroderma such as Netherton's syndrome), pigmentation, or extensive scarring that in the opinion of the investigator may interfere with the evaluation of LP lesions or compromise participant safety;
  • Immunocompromised (e.g., lymphoma, acquired immunodeficiency syndrome, or Wiskott-Aldrich syndrome);
  • Chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungals within 2 weeks before baseline;
  • Active acute bacterial, fungal, or viral skin infection (e.g., herpes simplex, herpes zoster, chickenpox, clinically infected AD, or impetigo) within 1 week before baseline.
• Any serious illness or medical, physical, or psychiatric condition(s) that, in the investigator's opinion, would interfere with full participation in the study, including administration of study drug and attending required study visits; pose a significant risk to the participant; or interfere with interpretation of study data. For example:
  • Clinically significant or uncontrolled cardiovascular disease, including unstable angina, acute myocardial infarction or stroke within 6 months from Day 1 of study drug application, New York Heart Association Class III or IV congestive heart failure, and arrhythmia requiring therapy or persistent uncontrolled hypertension (blood pressure > 150/90 mm Hg) unless approved by the medical monitor/sponsor;
  • Current or previous malignancy within 5 years of study entry, except basal or squamous cell skin cancer with removal considered to be curative, superficial bladder cancer, prostate intraepithelial neoplasm, carcinoma in situ of the cervix, or other noninvasive or indolent malignancy with sponsor approval;
  • Unstable asthma or COPD requiring systemic treatment (such as intravenous steroids) or hospital admission or emergency department treatment within 3 months from baseline or stable asthma or COPD requiring budesonide more than 720 µg/day (2 puffs BID of 180-μg dose) or fluticasone more than 440 μg/day (2 puffs BID of 110-μg dose) or other equivalent inhaled corticosteroids;
  • Current and/or history of arterial or venous thrombosis, including deep venous thrombosis and pulmonary embolism;
  • Current and/or history of active tuberculosis or current and/or history of latent tuberculosis unless adequately treated;
  • History of severe anemia, severe thrombocytopenia, or severe neutropenia.
• Any of the following clinical laboratory test results at screening:
  • Cytopenias, defined as follows:
    • Hemoglobin < 100 g/L (i.e., 10 g/dL);
    • Absolute neutrophil count < 1.5 × 10^9 /L (i.e., 1500/µL);
    • Platelet count < 1 × 10^11/L (i.e., 100,000/µL).
  • Liver function tests:
    • AST or ALT ≥ 2.5 × ULN;
    • Total bilirubin > 1.5 × ULN unless Gilbert's syndrome.
  • Estimated glomerular filtration rate < 30 mL/min/1.73 m^2 (using the Chronic Kidney Disease Epidemiology Collaboration equation);
  • Positive serology test results at screening for HIV antibody;
  • History of acute or chronic active hepatitis B or C virus infection. Participants who have recovered or have been successfully treated with no evidence of active hepatitis B or C infection and those who are immune due to hepatitis B vaccination can enroll. Participants who are positive for the hepatitis B surface antigen will be eligible if they are negative for HBV DNA; participants who are positive for the anti-HCV antibody will be eligible if they are negative for HCV RNA;
  • Any other clinically significant laboratory result that, in the opinion of the investigator, poses a significant risk to the participant.
• Use of any of the following treatments within the indicated washout period before the baseline visit:
  • 5 half-lives or 12 weeks, whichever is longer – biologic agents (e.g., dupilumab). For biologic agents with washout periods longer than 12 weeks (e.g., rituximab), consult the medical monitor;
  • 4 weeks – systemic corticosteroids or adrenocorticotropic hormone analogs, cyclosporine, methotrexate, azathioprine, or other systemic immunosuppressive or immunomodulating agents (e.g., mycophenolate or tacrolimus);
  • 2 weeks or 5 half-lives, whichever is longer – strong systemic CYP3A4 inhibitors;
  • 2 weeks – systemic antibiotics and immunizations with live-attenuated vaccines, sedating antihistamines unless on a long-term stable regimen (nonsedating antihistamines are permitted);
  • Note: Live-attenuated vaccines are prohibited during the DBVC period. COVID-19 vaccination is permitted;
  • 2 weeks – treatment with topical therapy (e.g., topical corticosteroids, pimecrolimus, and tacrolimus).
• Current treatment or treatment within 30 days or 5 half-lives (whichever is longer) before the baseline visit with another investigational medication or current enrollment in another investigational drug protocol.
• Pregnant or lactating participants, or those considering pregnancy during the period of their study participation.
• History of alcoholism or drug addiction within 1 year before screening or current alcohol or drug use that, in the opinion of the investigator, will interfere with the participant's ability to comply with the administration schedule and study assessments.
• Previous treatment with systemic or topical JAK inhibitors (e..g, ruxolitinib, tofacitinib, baricitinib, filgotinib, lestaurtinib, pacritinib).
• Inadequate venous access in nonlesional areas or in areas not treated by the study drug.
• Known allergy or reaction to any of the components of the study drug.
• In the opinion of the investigator, are unable or unlikely to comply with the administration schedule and study evaluations.
• Committed to a mental health institution by virtue of an order issued either by the judicial or the administrative authorities.
• Employees of the sponsor or investigator or otherwise dependents of them.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 9/21/22. Questions regarding updates should be directed to the study team contact.