Transcript

Lee Tetreault:

Hello and welcome to Frequently Asked Questions from the session 'Medical Update: New Drugs in Primary Care Practice'. We are joined today by Dr. Gerald Smetana. Doctor, before we start, can we go into a quick summary of today's session? 

Dr. Smetana:  

Sure, good afternoon. Today, I had a chance to talk with our attendees about some of the most important advances in pharmacotherapy that could potentially be relevant in primary care practice and represent novel additions to our existing treatments. I've opted to focus on three drugs in particular, which we'll be discussing during our podcast today.

Lee Tetreault:

Great, let's get into some frequently asked questions starting with SHINGRIX. First, how long does arm pain last after the shingles vaccine? 

Dr. Smetana:  

That's one of the most important questions people have asked and also my patients ask quite frequently. Arm pain is the most common side-effect after the shingles vaccine. It affects about as many as 80% of patients getting the vaccine and it can last commonly up to a week or sometimes more, but for practical matters, I tell patients, "You should expect this for about a week."

Lee Tetreault:

Can SHINGRIX be given if there is a prior shingles attack? 

Dr. Smetana:  

It can. The CDC is recommending it for all persons over age 50 who are not immunocompromised regardless of their prior history of shingles or not. However, if we look at patients who've had shingles once before, the act of actually having shingles releases an amnestic antibody response, so the chance of getting it a second time is already diminished by virtue of having had it once before. While the vaccine is actually being recommended by the CDC, the initial baseline risk after having had shingles before is already substantially lower. This means the absolute benefit of the vaccine would be less. But I had that conversation with patients, and if they want to maximally reduce their risk even further, then they're eligible for the vaccine.

Lee Tetreault:

If patients can't get injection number two in less than six months after the first one, do we have to restart the series? 

Dr. Smetana:  

This has been a huge issue because there's been a distribution problem with the vaccine since it had very first came out last year. From the beginning, the manufacturer underestimated the interest in the vaccine and there hasn't been enough to meet the need. The question comes up in patients who are able to get the first vaccine dose but can't manage to get an appointment for the second one before the six-month window ends: What to do? Currently, there's no recommendation to repeat the series in this instance, but rather simply does to give the booster when it does finally become available. I think it's fair to say we don't know whether that provides a similar degree of benefit as getting it in the six-month window, which is what's recommended, but there's no recommendation to repeat if for some reason, that has to be delayed more than that.

Lee Tetreault:

Let's get into some questions regarding erenumab. First, is it okay to use with migraine with aura? 

Dr. Smetana:  

Erenumab is one of the most important recent advances in the management of patients with migraine and the two other novel drugs that work through the same CGRP mechanism. Erenumab works by a completely different mechanism than existing therapies. It's one of the first of biologicals that I think can gain widespread use in primary care. Erenumab is safe to use in patients who have migraine with aura, do not increase the risk of stroke or subject them to any additional risk. In fact, that's a group of patients in which it'll be particularly attractive to use, since the migraine with aura can be more disabling.

Lee Tetreault:

Is it safe to inject at home? 

Dr. Smetana:  

It is. There have been some post-marketing rare reports of hypersensitivity reactions, these are quite infrequent, they're not frequent enough that there's any recommendation that the injection has to be done in a supervised setting. From the very first injection, patients can self-inject, they don't have to do it in our office. Any patients who have not previously had experience giving injections, I might bring them into the office for the first visit simply to teach them how to use the injection, but not because there's any risk in doing it unsupervised at home.

Lee Tetreault:

What are the prior authorization criteria? 

Dr. Smetana:  

I imagine this is gonna be a moving target, and may vary depending on the particular insurance plan and the state in which we each practice. I have found in the first few times I prescribe, this has been mercifully, much easier to do than I expected. Kinds of things that may show up in the prior authorization criteria would be failure of at least two prior medication trials for prevention of migraine. There may also be a recommendation based on the number of days per month that patients take acute or abortive treatment, and the combination of those two may be important factors in whether it would be covered. In general, it has not been as onerous of a prior authorization hurdle as I expected when the drug first came on the market.

Lee Tetreault:

Doctor, what do you recommend regarding Botox or erenumab?

Dr. Smetana:  

Those are both used in a very similar circumstance. These would be for patients who have an indication for preventive therapy, such as, for example, beta-blockers, divalproex sodium or topiramate, who have not responded well to existing preventive therapies, or maybe have had side effects from several of those, that prevent their safe use. In that circumstance, if the migraines are disabling and existing preventive treatments don't work, or not tolerated, then we move to a third-line option. And when we find theirselves in that circumstance, either botulinum toxin injection which is given every 12 weeks, usually by a specialist, or erenumab or one of the other CGRP-based auto antibody mechanisms, which can be given safely at home and prescribed by us in primary care practice, either of them would be acceptable. I think the one advantage of the erenumab is it can be given at home, it doesn't require patients to go in actually for physically a visit every 12 weeks, and that's a big advantage. The cost is significant for both, but fairly similar for the two drugs.

Lee Tetreault:

Can you still use triptans if receiving erenumab for migraine prevention? 

Dr. Smetana:  

Yes, you can. In patients who are getting erenumab or one of the other CGR-based treatments for prevention of migraine, of the full repertoire of options that we have for abortive treatment of migraine, it's still available to us and can be used safely. The fact that somebody's on erenumab does not diminish the safety or the efficacy of any of the acute treatments, such as triptans. And while they're quite effective, they don't typically cause migraines to abort, but the optimal goal would be a 50% reduction in the migraine burden. Most patients, in fact, still do need some type of acute or abortive treatment, and the full repertoire, including triptans, can be used safely.

Lee Tetreault:

And, finally, let's get into some questions regarding baloxavir. First, can it be used together with oseltamivir if influenza is severe? 

Dr. Smetana:  

Baloxavir is a new drug that was just approved by the FDA two months ago and is not yet in pharmacies, so none of us as clinicians have any experience with it yet. It's gonna be novel. It'll be a drug that will be an option to us for next year's flu season once it becomes available. It can be used together with oseltamivir in selected patients with particularly severe influenza. Now, this has not been studied. The primary treatment trial that led to its approval was a trial of monotherapy, of one drug versus the other. However, they do work by different mechanisms, so it's safe to use the two together, and there may be some expanded benefit in patients at particularly risk for complications. But I think this is an area that we'd like to see some further study on. I wouldn't recommend doing that routinely in primary care practice yet.

Lee Tetreault:

Can resistance occur? 

Dr. Smetana:  

It can. Resistance is said to occur in the two primary trials that led to its approval. Somewhere between 2-10% of patients who were given a single dose of baloxavir were found to develop viral resistance when they were studied for that later. But the clinical significance of that is not really known at this point.

Lee Tetreault:

Will it cover oseltamivir-resistant strains? 

Dr. Smetana:  

It appears to cover many. It's not known whether it would be all. But, however, since they do work by a different mechanism, some patients who have an influenza that is resistant to existing therapy, which would be oseltamivir, can respond well to baloxavir. And I think that's gonna be a particularly important role. If in a certain community in a particular year, there's high likelihood of resistance to oseltamivir, then baloxavir would be the appropriate first-line drug in those communities.

Lee Tetreault:

What are the dose adjustments for weight? 

Dr. Smetana:  

This is one thing we have to remember to look up. The dose varies based on the weight of our patient. In patients who are 40-80 kilograms, the dose is a single dose of 40 milligrams of baloxavir times one. And for patients who are at least 80 kilograms or more, the dose would be 80 milligrams as a single dose.

Lee Tetreault:

Is it safe during pregnancy? 

Dr. Smetana:  

It was not studied in the trials, so safety is unknown, but for that reason, it's not currently going to be recommended for pregnant patients. Whether it would be safe or not is, I think, a subject of future study, but it's not currently recommended.

Lee Tetreault:

This is great information, Doctor. Thank you so much for your time today.