How are antibiotics used to prevent infection in myeloma patients? At what points would antibiotic therapy be considered?

How are antibiotics used to prevent infection in myeloma patients? At what points would antibiotic  therapy be considered?

Our goal always is to treat the myeloma because that is our biggest risk for any of our patients coming in with myeloma. That's our biggest threat to both mortality and morbidity for our patients. However infection is a close second. So during treatment, relapse, you know, all these time points, even with smoldering sometimes myeloma patients will have increased risk of infection because, again, the myeloma itself puts you at risk of infection. And so for us, you know, depending on what stage you're at, what your numbers are doing, you know, there's different levels of prevention that we do.

So some of my patients with smoldering disease that don't have active disease, that don't need treatment, but their immunoglobulins are low, we’ll actually give IVIG to help prevent infections because that's been their problem, they keep getting infections. All the way to when we start treatment for newly diagnosed myeloma, you know, pretty much everybody gets an antiviral medication because proteasome inhibitors as well as CD38 antibodies will knock down your immunity to where you're at a higher risk of shingles. And anyone that's ever had shingles before knows that that is not something that you want. And sometimes it can be in bad places like your eye where it can affect your vision. It can go to the brain. So most people get a rash that's really painful. so morbidity more than anything. But sometimes it can actually cause really serious side effects as well. So this is why it's so important to really continue that antiviral medicine until your doctor says it's okay to stop. Once you've had shingles, we actually keep you on for a really long time, probably forever,so that you never get it again.

Then in terms of other prophylaxis for newly diagnosed patients, really it depends on if your neutrophils are coming down. So again, you know, we have immunoglobulins that come from your, you know, normal plasma cells and B cells. You have T cells and NK cells in the background that are helping you fight infections in a different way. And then you have neutrophils and neutrophils are something that actually help fight bacterial infections. And if it gets low, then you're at a higher risk of bacterial infections like pneumonias or urinary tract infections. Those are usually the most common. But even skin cellulitis like MRSA. so these are patients that if they get neutropenic on treatment, we usually give something like GCSF to help their neutrophils come up. We might decrease the dose of the different treatments they're on based on what we think is causing it, and then we might give them antibiotics for prevention even if they haven't had an infection, but we see that neutrophil came down, for a week I might give an antibacterial just to keep them protected until their white count comes back up. So that’s sort of how we use prevention, you know, in newly diagnosed as well as relapsed refractory patients.

We see a lot more neutropenia in patients who have had lots of therapies because their bone marrow is a little bit more sensitive after having multiple therapies, but it can happen when you're newly diagnosed as well. While we're trying to figure out the right dose for you. And then when you talk about other treatments that now use T cells, so CAR-T cells, bispecifics, they can still cause neutropenia. So there's some patients where we will give antibacterials sometimes if their counts get too low. It does cause the immunoglobulins to go down. So we, we give lots of IVIG for these patients. And then the T cells themselves. So when we think about drugs like Bactrim, for instance, that is supposed to help prevent against a specific pneumonia called PJP pneumonia. It can sometimes help with other bacterial infections like UTIs and things, but the real purposes that we're trying to use it to make sure you don't get this PJP pneumonia. And it's a little controversial in terms of when we give it or not. Different doctors do it differently. for my practice, I tend not to give it  unless someone really is at risk of PJP pneumonia, meaning their T cells are really being plummeted by, let's say, CAR-T cells or T-cell redirected therapy. The main thing with Bactrim is that if someone starts it ,it can also decrease your neutrophil count
sometimes depending on what other medicines you're on with it. And it can make it look like your creatinine’s going up, for your kidneys, even though it doesn't really affect your kidneys. It's a test issue. So sometimes we we try to avoid it if someone already has renal problems or has neutropenia, we might use a different alternative drug.

Again, we definitely recommend PJP prophylaxis for everyone who's on, you know, CAR-T, at least for the first six months to a year. And then for anyone that's on a bispecific for BCMA, specifically, because that tends to cause a lot more infection issues. But for everything else, it really depends on the patient as to saying, should we give it or not? And that's why not everybody is on it. Then in terms of antibacterials, you know, we have lots of different options, but we want something that's easy. So oral that doesn't cause too many side effects and Levaquin is one of the antibacterials we have. And it works really well for patients who are neutropenic, it protects really well,
however, it can have some side effects. One of the big one is called a fluoroquinolone. And that group of antibiotics can put people who already have arrhythmias at a higher risk of arrhythmias, and more fatal or severe arrhythmias. So we make sure we don't give those to certain patients. we always do an EKG for those patients to make sure they're QTc is not prolonged. If it is, we actually don't give that drug.

The other, part of it is that there's a black box warning that can cause tendonitis for some patients, especially older patients. So we're always a little bit more careful to, to make sure that we've talked about that or, we change it to other drugs. So we have others like cefpodoxime or Vantin, that we can use instead. But that's sort of how we decide on the antibacterials.

So there's conflicting data on the use of medicines to prevent a specific type of lung infection called pneumocystis pneumonia. So, that's a drug called Bactrim that's used to prevent that. There's some data suggesting that giving that drug to patients with myeloma who are getting induction therapy may be helpful. But there's debate about how beneficial that is in the community. So you should not feel too compelled to press your doctor about being on Bactrim. There are similarly controversial evidence about levofloxacin which is a drug to prevent pneumonias. Most of us have reviewed those studies and have opinions one way or another. I personally am not routinely using those drugs in my practice because, the studies that were done to support them were done in the United Kingdom, where they manage myeloma a little differently than we do. And I don't know that the benefits that we're seeing there apply to my patients.