after joining the study, a set of initial examinations is performed. these include a review of medical history, physical examination, blood laboratory tests, and imaging studies to document the extent of the urothelial cancer.

the results are used to confirm eligibility for the trial and to establish reference values for later comparisons.

on day 1 of the first treatment cycle, the study medication is given by intravenous infusion.

participants in cohort a receive only pf-08634404 as a monotherapy; participants in cohort b receive pf-08634404 together with enfortumab vedotin (commercial name padcev 30 mg powder for concentrate for solution for infusion).

the exact dose, frequency and duration are defined by the study protocol and may be adjusted by the investigators based on safety and tolerability.

after the infusion, vital signs are recorded and blood samples are taken to check for any immediate side effects.

the patient is asked about any symptoms that could represent an adverse event, such as nausea, fatigue, or infusion‑related reactions.

treatment cycles are repeated according to the schedule defined in the protocol, typically every few weeks.

each cycle begins with another intravenous infusion of the same medication(s).

before each new infusion, laboratory tests and a brief clinical evaluation are performed to ensure the patient remains eligible to continue.

if laboratory values or reported symptoms indicate that the medication is causing significant toxicity, the investigators may modify the dose or delay the next infusion.

all changes follow predefined safety criteria that aim to protect the participant.

after a predefined number of cycles (for example, every two or three cycles), imaging studies such as CT or MRI are repeated.

the purpose is to evaluate the antitumor activity of the treatment by measuring changes in tumor size.

treatment continues until one of the following occurs: disease progression as shown by imaging, occurrence of unacceptable toxicity, completion of the planned number of cycles, or a decision by the investigator that continuation is no longer beneficial.

when treatment stops, a final assessment is performed. this includes a physical exam, laboratory tests, imaging, and a comprehensive review of any adverse events that occurred during the study.

after the end‑of‑treatment visit, scheduled follow‑up visits are conducted to monitor long‑term safety and survival.

these visits may include blood tests and imaging at intervals defined by the protocol, extending for several months after the last dose.