An open label extension (OLE) study offered to subjects with Chronic Spontaneous Urticaria that have completed the AK006-001 (NCT06072157) Part C referred to as the Main study portion of the study. Qualified subjects will receive up to four doses of the study drug (AK006) through an intravenous infusion every 4 weeks. There is a 16-week follow up period once all the scheduled infusions have been completed. Subjects will be follow for evaluation of safety, tolerability, PK, immunogenicity, and clinical response.

Key Inclusion Criteria:

• Enrolled in Part C of Study AK006-001 (NCT06072157) and completed the randomized, double-blind, placebo-controlled treatment period and the Day 99 Visit.
• Acceptable demonstration of tolerance to study drug during the AK006-001 study as determined by the investigator.
• Acceptable demonstration of protocol compliance during the AK006-001 study as determined by the investigator.
• Female subject of childbearing potential and male subject with female partner of childbearing potential must agree to use a highly effective method of contraception with <1% failure rate or abstain from sexual activity from Screening until the end of the study, or for 16 weeks following the last dose of AK006, whichever is longer.

Key Exclusion Criteria:

• Pregnant, breastfeeding, or planning to become pregnant while participating in the study.
• Planned use of an approved or investigational therapy to treat CSU other than a single 2nd- or later-generation H1-AH between 1× and 4× the licensed dose and frequency, during the study.