This clinical trial is an extended clinical trial for test subjects who participated in the phase 3 clinical trial of PT_BTA_P3_21 (clinical trial plan number) and completed follow-up observation up to 16 weeks after administration of clinical trial drugs, and evaluates the effectiveness and safety of repeated administration of protoxin in those with moderate or severe brow wrinkles.

Inclusion Criteria:

• PT_BTA_P3_21 (clinical trial plan number) Test subjects who participated in clinical trials and completed follow-up observation up to 16 weeks after administration of clinical trial drugs
• Men and women aged between 19 to 65 years old
• Subjects attaining ≥grade 2(moderate) in the investigator's rating of the severity of glabella lines at maximum frown
• Those who understand and comply with clinical trial procedures and visit schedules
• Subjects who voluntarily decides to participate and signs the consent form after hearing the explanation of this clinical trial.

Exclusion Criteria:

1. A person who has or is accompanied by the following diseases at the time of screening

   1. A person with systemic neuromuscular junction disorder that can affect neuromuscular function [myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome, amyotrophic lateral sclerosis (ALS), etc.]
   2. A person with a history of facial paralysis or ptosis
   3. A person who has skin abnormalities such as infections, skin diseases, scars, etc. at the site to be administered

2. A person who has wrinkles to the extent that the glabellar lines cannot be physically flattened, such as when wrinkles are not straightened by hand

3. A person who is taking the following drugs

   1. Within 4 weeks of screening: Drugs with muscle relaxation action, such as muscle relaxants, spectinomycin hydrochloride, aminoglycoside antibiotics, polypeptide antibiotics, tetracycline antibiotics, lincomycin antibiotics, anticholinergics, benzodiazepines and similar drugs, and benzamide drugs [However, for muscle relaxants, benzodiazepines and similar drugs, a person who has stably maintained administration of them from within 4 weeks from the time of screening (the same drug is maintained without changing the usage and dose), and is not expected to change in ingredients, usage, and dose of them during the clinical trial period can be enrolled]
   2. A person who has administered aspirin or NSAIDs within 7 days before administration of the investigational product (However, low-dose aspirin (100 mg/day or less) administered for antithrombotic purposes is permitted)

4. A person who has had procedure/surgery that may affect the wrinkles around the glabellar or forehead during the following period

   1. Within 48 weeks of screening: Tissue augmentation
   2. Within 24 weeks of screening: A person who has undergone facial plastic surgery including glabellar lines such as brow lift, dermal resurfacing, or peeling, etc.

5. A person with a history of surgery or treatment around the orbit (except for double eyelid surgery, epicanthal fold (Mongolian fold) correction)

6. A person who is planning to undergo facial cosmetic procedures such as dermal filler, photorejuvenation, chemical peeling, and dermabrasionduring the clinical trial period

7. PT_BTA_P3_21 (Clinical Trial Plan Number) A person who received similar drugs for clinical trials such as botulinum toxin A and B after visiting the end of phase 3 clinical trials)

8. A person who is expected to administer botulinum toxin formulations other than this investigational product during the clinical trial period

9. A person with a history of hypersensitivity or allergy to the components of the investigational product (botulinum toxin formulations and serum albumin, etc.)

10. A person with a history of alcohol or drug addiction

11. A person who, in the investigator's judgment, may affect clinical trial participation or objective efficacy evaluation results, due to anxiety disorders or other significant psychiatric disorders (e.g., severe depression)

12. Women and men of childbearing potential who plan to become pregnant or do not intend to use appropriate contraceptive methods* during the clinical trial period

    * Appropriate contraceptive methods

    1. Using either hormonal contraceptives (subcutaneous implants, injections, oral contraceptives, etc.) or spermicide in combination with physical barrier methods (condoms, contraceptive diaphragms, vaginal sponges, cervical caps)
    2. Implantation of an intrauterine device or intrauterine system: A copper loop, hormone-containing intrauterine system
    3. Both men (condoms) and women (contraceptive diaphragms, vaginal sponges or cervical caps) use physical barrier methods together
    4. Surgical sterilization procedure/surgery: Bilateral tubal ligation, vasectomy, etc.

13. Pregnant or lactating women

14. A person with serious comorbidities (e.g., malignant tumors, immunodeficiency (decreased immune function), renal disease, liver disease, heart disease, respiratory disease, etc.) or acute diseases that are unsuitable for participation in the clinical trial as judged by the investigator

15. A person who participated in other clinical trials/clinical device trials within 30 days prior to screening and received administration/treatment of investigational products/devices, or a person for whom the longer period has not passed between the above period and 5 times the half-life of the investigational product in the clinical trial in which they participated

16. Others who are judged inappropriate to participate in this clinical trial by the investigator