Role of L-Glutamine in SCD

EP: 1.Understanding Sickle Cell Disease

EP: 2.Prevalence and Burden of SCD

EP: 3.Acute and Chronic Complications in SCD 

EP: 4.Anemia-Related SCD Manifestation: Monitoring and Screening

EP: 5. Impact of SCD on Quality of Life

EP: 6.Hydroxyurea in Sickle Cell Disease

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EP: 7.Role of L-Glutamine in SCD

EP: 8.Screening and Monitoring for Red Blood Cell Transfusion

EP: 9.Considerations for HSCT in Sickle Cell Disease

EP: 10.Benefits and Risks of HSCT in SCD

EP: 11.A Look at Voxelotor: HOPE Trial

EP: 12.Voxelotor Use in the COVID-19 Pandemic

EP: 13.Use of Crizanlizumab for Pain Crisis Associated With SCD

EP: 14.Therapeutic Decision Making in SCD

EP: 15.Gene Therapy Approaches in SCD

EP: 16.Emerging Gene Therapy Methods in SCD

EP: 17.Stem Cell vs Gene Therapy Processes in SCD

EP: 18.Challenges in Global Access to SCD Treatments

EP: 19.What’s Next and Final Thoughts in SCD

Ifeyinwa (Ify) Osunkwo, MD, MPH: Wally, in 2017 the FDA approved L-glutamine, or Endari, for sickle cell disease. Can you tell us about how that works and what has been the uptake of Endari in the sickle cell disease population?

Wally Smith, MD: Endari has special appeal. Patients like “natural” medications. I have a lot of patients who come to me and tell me they have a vitamin or a combination of vitamins or a natural thing that they discovered that they want to try and is it OK with me if they take that. And I usually say yes after doing research. Glutamine is a protein. It’s a normal protein; it’s in our bodies. We normally don’t get that much in the food that we eat. But researchers in California decided that because of some of the actions of glutamine, and I won’t go into the ATP [adenosine triphosphate] and the way it works. But what if we gave 40 times the amount of glutamine that you would normally get from food, what would happen to your blood? And voila, the cells got better. They got healthier, and there were no adverse effects, with maybe just a little nausea. And in a trial, they were able to show a decrease from an average of 4 to an average of 3 crises per year. Now people yawned when that data came out. “You mean all you did was decrease it from 4 crises to 3?” But I stood up for that. I said, “You know what, 1 crisis matters.”

Ifeyinwa (Ify) Osunkwo, MD, MPH: For a patient, yes.

Wally Smith, MD: One crisis could kill you. One crisis means 1 less time per year that you’re in the hospital. And by the way, you can give this to children as young as 6. You have a medicine that’s natural, and the only downside that I see about it, it’s a powder, and you have to put it on food, or put it in water, or stir it in liquids. People have a distasteful way of taking it, making a slurry out of it. And it’s twice a day. Other than that, I can’t think of a downside to taking L-glutamine. Now what you didn’t ask me is, do people actually take it?

Ifeyinwa (Ify) Osunkwo, MD, MPH: That was my next question. And the answer is?

Wally Smith, MD: No. And why not? It has all the downsides of hydroxyurea. “I don’t feel anything when I take hydroxyurea. I don’t feel anything when I take L-glutamine. I don’t get a result immediately when I take hydroxyurea. It’s more like a vitamin.” L-glutamine sort of is a vitamin; it’s a protein. “And nothing happens when I take it. And by the way, I’ve got to go to the trouble of mixing it up, and drinking it down, and I don’t like mixing it up and I don’t like drinking it down. Can I just go to the general nutrition store and get some of that powder? If I’m going to take a powder, can I just go get me a big box of that powder and take it that way?” That’s been the knock against L-glutamine. Having said all that, I do have individuals who’ve taken L-glutamine and gotten a response. Not only have they gotten a response in their total number of crises per year, but a few of them, and only a few, have had improvements in their hemoglobin. If I were to pick the least toxic of all medications available to treat sickle cell disease, I would pick L-glutamine.

Ifeyinwa (Ify) Osunkwo, MD, MPH: That pretty much sums it up. It’s a vitamin; it’s natural. People love the idea of a natural medicine, but the issue Wally mentioned was, you still have to take it. And by the way, it’s twice a day, and it’s a slurry. You’ve got to mix it into food or water or juice, and you’ve got to like the taste and get it down into your body. At the end of the day, any therapeutic intervention has to meet certain criteria. It has to be effective. It has to be palatable and has to be acceptable to the people who are going to take the medication. And that been the push and pull with any sickle cell therapy we have available.

Transcript Edited for Clarity