Phase 1/2 study enrolling up to 60 healthy volunteers in Phase 1 followed by approximately 150 subjects with acne vulgaris in Phase 2.

Phase 1/2 study enrolling up to 60 healthy volunteers followed by approximately 150 subjects with acne vulgaris. Data from Phase 1 stage will be reviewed before progressing to Phase 2.

Phase 1 is an open label study to determine safety, tolerability of XPF-005 topical gel and exposure of XEN801 (active ingredient). Up to 5 cohorts of 12 healthy volunteers will each receive different dose volumes of XPF-005 gel or Placebo gel on their face and back for 14 or 21 days. Safety assessments are completed and PK samples are collected at study visits.

Phase 2 is a randomized, double-blind, vehicle-controlled, parallel-group study to determine safety, tolerability, efficacy of XPF-005 topical gel and exposure of XEN801 (active ingredient). Approximately 150 subjects with acne vulgaris will apply XPF-005 or matching placebo gel on their face for 12 weeks. Safety and efficacy assessments are completed and PK samples are collected at study visits.

Safety assessments include local skin tolerability assessments, vital signs, physical examination, 12-lead ECG, safety laboratory blood and urine and adverse event reporting.

Efficacy assessments include acne lesion counts and Investigator's Global Assessment (IGA).

Key Inclusion Criteria:

1. Aged between 18 and 50, inclusive

2. Male or female, agree to comply with contraceptive requirements

3. Signed Informed Consent Form

4. Clinical diagnosis of facial acne vulgaris defined as:

   • 25 to 75 inflammatory lesions,
   • 20 to 120 non-inflammatory lesions, and
   • an IGA score of ≥3

5. Agree to refrain from using any topical acne treatments on the face or any oral acne treatments. Topical acne treatment that do not have significant or measurable systemic absorption are permitted for treatment of the back, shoulders, and chest only

Key Exclusion Criteria:

1. Known sensitivity to any topical or dermal product, including alcohol
2. Female who is breast feeding, pregnant, or planning to become pregnant
3. Any skin condition of the face other than acne vulgaris
4. Two or more active nodular lesions
5. Excessive facial hair that would interfere with the evaluation of safety or with the diagnosis or assessment of acne vulgaris
6. Use of tanning beds/booths, or excessive sun exposure
7. Use of over-the-counter topical medications for treatment of acne vulgaris on the face within 14 days of baseline
8. Use of systemic corticosteroids, antibiotics, anti-acne drugs, anti-inflammatory drugs (NSAIDs are permitted) or prescription topical retinoid use on the face within 28 days prior the baseline
9. Initiation of hormonal therapy or dose change to hormonal therapy within 12 weeks prior to baseline.
10. Use of androgen receptor blockers (eg, spironolactone, flutamide) within 12 weeks prior to baseline
11. Use of oral retinoid (eg, isotretinoin, alitretinoin) within 12 months prior to baseline and vitamin A supplements >10,000 units/day within 6 months prior to baseline
12. Facial procedures (eg, microdermabrasion, chemical or laser peel) within 8 weeks prior to baseline
13. Photodynamic therapy within 12 weeks prior to baseline
14. Any other reason that would make the subject, in the opinion of the Investigator or Sponsor, unsuitable for the study