Drs Langer and Vidula describe the coverage considerations for the diagnostic test required for the use of oral selective estrogen receptor degraders, best practices associated with its use, and the recommended duration of treatment.
Ryan Haumschild, PharmD, MS, MBA: That brings me to the question, when we look to our managed care and payer experts a lot of times when we’re doing testing or developing these treatment pathways, I also want to make sure that there’s some type of payer coverage to get reimbursed or to reduce the out-of-pocket expense for our patient.Dr [Lucy] Langer, being the managed care executive with us today, can you describe the coverage considerations of the diagnostic test that’s used for oral SERDs [selective estrogen receptor degraders] and any best practices with its use thus far?
Lucy R. Langer, MD, MSHS: I’m speaking from the UnitedHealthcare perspective, I’m not speaking for other payers. But we do have a policy that covers companion diagnostics. If there is a companion diagnostic, we will cover that test. Unlike the broad coverage for comprehensive genomic profiling, for example. So, there are specific companions that we cover and if it’s a single gene test or if it’s a small, targeted panel, we cover those tests as well. My thinking about this is that while we know that the future is moving toward more comprehensive genomic profiling and more and more markers are becoming evident through that, there’s also a lot of information that comes out of those tests that we really don’t need to get in a sequential or serial way. When we are thinking about serial testing after you’ve done the primary test, we want to think about what the targeted test is—what’s the targeted panel that we can be ordering and covering?
Ryan Haumschild, PharmD, MS, MBA: Excellent. When we think about the ESR1 [estrogen receptor 1] mutation and we think about coverage, we think about testing, it’s also important for [individuals] to understand the pathophysiology of ESR1 and how it can come up again. Are you able to speak to that at all as well?
Lucy R. Langer, MD, MSHS: The ESR1 mutation causes the estrogen receptor to be constituently active and it causes a mutation or a change in the ligand-binding domain. So those types of drugs, like a SERM [selective estrogen receptor modulator], for example, that might bind to the ligand…there’s going to be resistance to those. The SERDs on the other hand aren’t necessarily dependent on the ligand-binding domain, but they are dose dependent. So even with fulvestrant, you can see with an increasing dose that you can overcome that. But the injection of fulvestrant makes it a challenge to increase the dose because patients already have a lot of discomfort and may not stay on the medication for the duration that they should or tolerate the higher dose. So these SERDS are really filling a void there that can help you overcome that resistance.
Ryan Haumschild, PharmD, MS, MBA: That was a great overview. One of the things that you mentioned that I just want to highlight quickly is thinking about the duration of treatment. As we set expectations for our providers and our patients, a lot of times we’re going to go to the clinical trial data. Dr Vidula, you could shed a little bit more light on that. What is the recommended duration of treatment with oral SERDs for our ER+ [estrogen receptor positive]/HER2- metastatic breast cancer patients?
Neelima Vidula, MD: In general, for patients with ER+/HER2- metastatic breast cancer, they’ll remain on a specific treatment unless there’s evidence of clear progression of the disease or they’re experiencing unacceptable toxicity. When I counsel patients in clinic about starting an oral SERD—the approved one, of course, is elacestrant—I will let them know that the median progression-free survival [PFS] in the study that led to its approval, the EMERALD [NCT03778931] study, was 3.8 months, but they could be on it for a shorter duration or a longer duration. And it just depends on the clinical course and how the metastatic cancer behaves for them. Typically what we’ll do is we’ll be assessing these patients regularly in clinic. At least once a month we’ll be seeing them. We’ll be assessing for symptoms and evaluating for any new signs of a recurrence, so that clinical piece is key. It’s also important to monitor laboratory parameters such as liver function tests to make sure there’s no elevation in these enzymes that might cue you into the growth of liver metastases—that’s a common site of metastasis of ER+/HER2- breast cancer. Additionally, it’s important to get imaging scans periodically. Typically, for most endocrine and targeted therapies, we’ll get scans every 3 cycles, every 3 months or so, unless a patient is having symptoms or some reason for us to think that there’s earlier progression. You can also certainly monitor tumor markers. If they’re elevated at baseline at the time of diagnosis of ER+/HER2- advanced breast cancer, then it’s OK to track them once a month or so. And if they suddenly are rising, I typically don’t change a patient’s treatment based on tumor marker changes alone. But if they are rising, I might consider getting a CT scan earlier than we typically would just to see if there’s evidence of progression. But in general, a patient will stay on the treatment and that includes oral SERDs unless there’s definitive evidence of disease progression or they’re having adverse effects that we can't manage.
Ryan Haumschild, PharmD, MS, MBA: Sounds like you provide great vigilance because that’s what patients need; you want to make sure they aren’t experiencing adverse effects. Is that going to start us having conversations about the need to transition to another therapy or really treat the progression? And as you mentioned, we’re looking at median PFS. So, some patients can be on the upper limits of normal, some can be on the lower, and that’s why you’re constantly looking at your tumor markers in your scans to evaluate what’s best for this patient.
Transcript edited for clarity.