Management of Patients With Treatment-Resistant Metastatic Prostate Cancer

Adverse Effects

Mark Klein. What are the AEs people are seeing from using apalutamide, enzalutamide, and abiraterone? What are they seeing in their practice vs what is in the studies? When I have had to stop people on abiraterone or drop down the dose, almost always it has been for fatigue. We check liver function tests (LFTs) repeatedly, but I can’t remember ever having to drop down the dose or take it away even for that reason.

Elizabeth Hansen. The toxicities of these 3 agents are very different. In my practice I have seen a few patients develop hepatotoxicity with abiraterone, and I think this reflects the known incidence of transaminitis (grade 3/4) seen in clinical trials, reported at 6%. Generally, we’ve been able to restart treatment by withholding abiraterone until liver function returns to baseline and then subsequently dose reducing. Like Julie mentioned, abiraterone should be used with caution and/or avoided in patients with serious cardiac disease, recent myocardial infarction, or heart failure. I also always check blood pressure history, to ensure it is well controlled prior to initiation, and order a home blood pressure cuff for monitoring. With enzalutamide one of the main concerns is fatigue, which occurred in > 10% of patients in clinical trials. In my experience this has been dose limiting and can be managed with dose reductions. Seizures also occurred in 0.4% of patients on enzalutamide, so I always ask about seizure history and screen the medication list for concomitant medications that may lower the seizure threshold or other risk factors such as brain metastasis. Last, enzalutamide is a strong CYP3A4 inducer, so there is a strong possibility for drug interactions with other medications, and it is associated with increased cardiac events. With apalutamide you have the cardiac concerns, thyroid dysfunction, fracture risk, and drug interactions to worry about as well. To be honest, we have not used this agent yet at my practice.

Mark Klein. At the Minneapolis VA Health Care System (MVAHCS) when apalutamide first came out, for the PSA rapid doubling, there had already been an abstract presenting the enzalutamide data. We have chosen to recommend enzalutamide as our choice for the people with PSA doubling based on the cost. It’s significantly cheaper for the VA. Between the 2 papers there is very little difference in the efficacy data. I’m wondering what other sites have done with regard to that specific point at their VAs?

Elizabeth Hansen. In Columbus, we prefer to use either abiraterone and enzalutamide because they’re essentially cost neutral. However, this may change with generic abiraterone coming to market. Apalutamide is really cost prohibitive currently.

Julie Graff. I agree.

Patient Education

Mark Klein. At MVAHCS, the navigators handle a lot of upfront education. We have 3 navigators, including Kathleen Nelson who is on this roundtable. She works with patients and provides much of the patient education. How have you handled education for patients?

Kathleen Nelson. For the most part, our pharmacists do the drug-specific education for the oral agents, and the nurse navigators provide more generic education. We did a trial for patients on IV therapies. We learned that patients really don’t report in much detail, but if you call and ask them specific questions, then you can tease out some more detail.

Elizabeth Hansen. It is interesting that every site is different. One of my main roles is oral antineoplastic monitoring, which includes many patients on enzalutamide or abiraterone. At least initially with these patients, I try to follow them closely—abiraterone more so than enzalutamide. I typically call every 2 to 4 weeks, in between clinic visits, to follow up the laboratory tests and manage the AEs. I always try to ask direct and open-ended questions: How often are you checking your blood pressure? What is your current weight? How has your energy level changed since therapy initiation?