Intervention: Fenebrutinib
Trial phase: Phase 2
SMILES: C[C@H]1CN(C2COC2)CCN1c1ccc(Nc2cc(-c3ccnc(N4CCn5c(cc6c5CC(C)(C)C6)C4=O)c3CO)cn(C)c2=O)nc1
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 24
Group description: Participants received GDC-0853 200mg twice daily from Day 1 to 56.
Eligibility criteria:
Inclusion Criteria:

Aged 18-75 years, inclusive
Diagnosis of chronic spontaneous urticaria (CSU) refractory to H1 antihistamines at the time of randomization
Willing and able to complete an Urticaria Participant Daily eDiary for the duration of the study
No evidence of active or latent or inadequately treated infection with tuberculosis (TB)
Partcipants with a history of Bacille Calmette-Guérin (BCG) vaccination should be screened using the QuantiFERON-TB-Gold (QFT) test
Only for participants currently receiving proton-pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs): Treatment must be at a stable dose during the 2-week screening period prior to randomization and with a plan to remain at a stable dose for the duration of the study
For women of childbearing potential: Agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods that result in a failure rate of <1% per year during the treatment period and for at least 4 weeks after the last dose of study drug. Women must refrain from donating eggs during this same period.

Exclusion Criteria:

Treatment with omalizumab or other monoclonal antibody therapies used to treat CSU within 4 months prior to screening or primary nonresponse to omalizumab
Use of a non-biologic investigational drug or participation in an investigational study with a non-biologic drug within 30 days prior to study drug administration on Day 1 (or within 5 half-lives of the investigational product, whichever is greater)
Use of a biologic investigational therapy or participation in an investigational study involving biologic therapy within 90 days or 5 half-lives, whichever is greater, prior to study drug administration on Day 1
Previous treatment with GDC-0853 or other Bruton's tyrosine kinase (BTK) inhibitors
Participants whose urticaria is solely due to physical urticaria
Other diseases with symptoms of urticaria or angioedema, including urticarial vasculitis, urticaria pigmentosa, erythema multiforme, mastocytosis, hereditary or acquired angioedema, lymphoma, or leukemia
Atopic dermatitis, bullous pemphigoid, dermatitis herpetiformis, or other skin disease associated with itch such as psoriasis
Routine doses of the following medications within 30 days prior to screening: systemic or cutaneous (topical) corticosteroids (prescription or over the counter), hydroxychloroquine, methotrexate, cyclosporine, or cyclophosphamide
Prior utilization of intravenous (IV) steroids for treatment of laryngeal angioedema
Intravenous immunoglobulin G (IV IG) or plasmapheresis within 30 days prior to screening
History of anaphylactic shock without clearly identifiable avoidable antigen
Hypersensitivity to GDC-0853 or any component of the formulation
Major surgery within 8 weeks prior to screening or surgery planned prior to end of study (12 weeks after randomization)
Require any prohibited concomitant medications
History of live attenuated vaccine within 6 weeks prior to randomization or requirement to receive these vaccinations at any time during study drug treatment
Evidence of clinically significant cardiac, neurologic, psychiatric, pulmonary, renal, hepatic, endocrine, metabolic, or gastrointestinal (GI) disease that, in the investigator's opinion, would compromise the safety of the participant, interfere with the interpretation of the study results or otherwise preclude participant participation
Current treatment with astemizole, terfenadine, and/or ebastine
Uncontrolled disease states, such as asthma, psoriasis, or inflammatory bowel disease, where flares are commonly treated with oral or parenteral corticosteroids