Order the med to minimize delays in therapy, you may be able to get billing sorted out today.
Each HIV manufacturer has their own manufacturer patient assistance, and I'd recommend becoming familiar with each of them and also with your local reps/MSLs. Your MSLs are going to be your best friends.
For Biktarvy, you may be able to utilize the Gilead Advancing Access Program. If there's a clinic you're working with, you can ask to be a part of their iAssist program for easier enrollment, otherwise you can utilize the faxes. Without iAssist, you can call Gilead's AAP and try for immediate conditional approval which would cover #30 for no copay (they allow a refill every 23 days so you could get two fills under that conditional approval). This is a great option for patients only on the one med, but I'd still recommend the patient be partnered with a benefits navigator to either enroll in state assistance or ADAP.
Is this patient new to ART or is this a continuation of therapy? If a continuation how were they getting Biktarvy before?