An exploratory open-label study of rosacea patients to study the efficacy and tolerability of erenumab in the prophylactic treatment of persistent redness and flushing attributed to rosacea. Approximately 30 subjects will be included in the study and receive erenumab 140 mg for three months. The study will begin June 2020 and is expected to last nine months.

Inclusion Criteria:

• Men and women between ages 18 - 65 years who have suffered from rosacea for at least 12 months.
• If patient has concurrent migraine, a daily headache diary must be filled out

Criteria to be met prior to enrollment in the 4-week run-in period:

•Erythematotelangiectatic rosacea with a minimum of 15 days of either:

• PSA > 2, and/or
• Moderate, severe or extreme flushing measured by the Flushing Assessment Tool (FAST)

Exclusion Criteria:

• Systemic treatment for rosacea ended less than five half-lives or 28 days ago, whichever is longest

• Topical treatment for rosacea ended less than five half-lives or 28 days ago, whichever is longest

• Cardiovascular disease of any kind, including cerebrovascular disease

• Hypertension on the experimental day (systolic blood pressure > 150 mmHg and/or diastolic blood pressure > 100 mmHg)

• Hypotension on the experimental day (systolic blood pressure < 90 mmHg and/or diastolic blood pressure < 50 mmHg)

• Ongoing psychiatric disease of any kind - unless it has been effectively treated with a stable treatment for at least 2 months.

• Anamnestic or clinical symptoms of any kind that are deemed relevant for study participation by the physician who examines the patient

• Pregnant or breastfeeding women, or women expecting to conceive during the study

• Women of childbearing potential who are unwilling to use an acceptable method of effective contraception during treatment through 16 weeks after the last dose of erenumab. Acceptable methods of effective birth control include not having intercourse (true abstinence, when this is in line with the preferred and usual lifestyle of the subject), hormonal birth control methods (pills, shots/injections, implants, or patches), intrauterine devices, surgical contraceptive methods (vasectomy with medical assessment of the surgical success of this procedure or bilateral tubal ligation), or two barrier methods (each partner must use one barrier method) with spermicide - males must use a condom with spermicide; females must choose either a diaphragm with spermicide, OR cervical cap with spermicide, OR contraceptive sponge with spermicide. Female subjects not of childbearing potential are defined as any female who: is post-menopausal by history, defined as:

  • Age ≥ 55 years with cessation of menses for 12 or more months, OR
  • Age < 55 years but no spontaneous menses for at least 2 years, OR
  • Age < 55 years and spontaneous menses within the past 1 year, but currently amenorrhoeic (e.g. spontaneous or secondary to hysterectomy), AND with postmenopausal gonadotropin levels (luteinizing hormone and follicle-stimulating hormone levels > 40 IU/L) or postmenopausal estradiol levels (< 5 ng/dL) or according to the definition of "postmenopausal range" for the laboratory involved OR Underwent bilateral oophorectomy OR Underwent hysterectomy OR Underwent bilateral salpingectomy

• Known sensitivity to any component of erenumab

• Previously randomized into an erenumab study

• Member of investigational site staff or relative of the investigator

• Unlikely to be able to complete all protocol required study visits or procedures, and/or to comply with all required study procedures to the best of the subject's and investigator's knowledge