Is anyone involved in clinical trials for ET, specifically for CALR?

Posted by lisanell @lisanell, Dec 30, 2025

Is anyone involved in any clinical trials for ET, specifically for CALR? I am unable to tolerate Hydroxyurea, and am currently only taking aspirin. I saw this one: “JNJ-88549968 for the Treatment of Calreticulin (CALR)-Mutated Myeloproliferative Neoplasms” on clinical trials.gov and other cancer center sites.

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Profile picture for drbart86 @drbart86

@drbart86 Got home from 2nd dose. Was higher and my body really reacted as well. I kept wondering how nobody else saw the trucks coming through 🥹. But other than the fatigue nothing else to bad. Final titration dose next week, then hopefully go on to maintenance doses on a 3 weeks schedule - without the hospital stay.
From my perspective, the antibody treatments to CALR look to be a huge step forward. Of the two I am aware of (different modes of action) these may be game changers for us.
I remain really thankful to the medical professionals, drug companies, and all the caregivers that support patients and to improve our quality of life. And I hope the best to all those on this journey.

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@drbart86

Bravo, bravo!!!!

Please get some rest and look both ways before crossing!!!

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Profile picture for drbart86 @drbart86

@drbart86 Got home from 2nd dose. Was higher and my body really reacted as well. I kept wondering how nobody else saw the trucks coming through 🥹. But other than the fatigue nothing else to bad. Final titration dose next week, then hopefully go on to maintenance doses on a 3 weeks schedule - without the hospital stay.
From my perspective, the antibody treatments to CALR look to be a huge step forward. Of the two I am aware of (different modes of action) these may be game changers for us.
I remain really thankful to the medical professionals, drug companies, and all the caregivers that support patients and to improve our quality of life. And I hope the best to all those on this journey.

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@drbart86 Thanks for posting your experiences. Once you come down from your latest session, can you tell us anything about the science behind the antibody treatment? What "bodies" are the "antis" fighting on the CALR landscape. Is there a link to the study? (Apologies if you posted this previously.) Many thinks from a fellow CALR!

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Briefly - Antibodies are what attach to "bad" things which then signal to macrophages and or "trained" (via prior exposure) immune cells to kill the invader (i.e. pathogen). For the CALR mutation, antibodies have been developed to attach to the mutated protein. At this point I am aware of 2 products currently undergoing human trials. One this the antibody alone, and from my understanding mainly just regulates production (I would guess similar to other cytoreductive agents (HU, Jakafi, etc)) but would likely not have the side-effects of lowered RBC, etc. as it is only attacking the specific CALR mutated cell. The second is the antibody that is also attached to another "killer" immune cell, that when attached to the CALR mutant cell will then kill the cell. This called a Bispecific Antibody (or you may see as a BiTE treatment = Bispecific T-cell Effector). From what I have seen, the first product (by Incyte) has a very high tolerance level and early results look good. The BiTE treatment should be more effective, possibly with greater potential side-effect risk (From Johnson & Johnson).

This is my best lay interpretation of these technologies. But, I will not claim to have all the details exactly correct - that is where you need to work with your specialist. For the phase 1 trial, I believe the number of patients is a total of 220 worldwide and for my trial site is a total of 9; so I would expect that the number at and center would be similar. What would be interesting to know would be the criteria that are used to determine final dosing. My final dose will be fairly low compared to another that I have has contact with. I only have ET, they have MF.

Hopefully once I get my dose settled in and "routine" maybe my symptom load (mostly severe fatigue) will go back a few years and my "normal" will be more enjoyable - as the song goes - "I'm much to young to feel so damn old"!!!

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Profile picture for flannery @flannery

Ì have been taking hydroxurea and ĥave had severe reactions: severe vomiting and what my hematologist calls "not common" side effects. Have tried Anagrelude but the side effects were worse. Has anyone tried the Besremi or Jakifi previously mentioned?

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@flannery I was on Jakafi for about 5 years; started this after HU no longer liked me after about 4 years on it. For me it has mostly just been increasing fatigue on Jakafi that is most troublesome for me - is this due to disease, Jakafi, both???
Good luck on your journey and hope you find a treatment that fits you.

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Profile picture for flannery @flannery

Ì have been taking hydroxurea and ĥave had severe reactions: severe vomiting and what my hematologist calls "not common" side effects. Have tried Anagrelude but the side effects were worse. Has anyone tried the Besremi or Jakifi previously mentioned?

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@flannery
Hello Friend, I am sorry you are experiencing such difficulties with HU
I WAS ON IT AND DID NOT HELP ME TO REDUCE MY SYMPTOMS FROM PV POLYCYTHEMIA VERA
YES I DID TAKE JAKAFI
I BELIEVE IT IS MUCH BETTER TOLERATE ! I liked TAKING IT ! So SPEAK WITH YOUR DOCTOR ABOUT JAKAFI! I would SUGGEST STARTING ON LOWER DOSE FIRST
I TOOK IT FOR ABOUT TWO YEARS BUT MY DOSE WAS TOO HIGH !
It brought ALL MY BLOOD NUMBERS LOWER THAN I WANTED ! So got off !
I AM ON OJJAARA NOW FOR TEN MONTHS !
Good drug VERY VERY EXPENSIVE BUT I HAVE NOW ALTERNATIVE !
Good luck 🍀
Best wishes

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Profile picture for drbart86 @drbart86

Briefly - Antibodies are what attach to "bad" things which then signal to macrophages and or "trained" (via prior exposure) immune cells to kill the invader (i.e. pathogen). For the CALR mutation, antibodies have been developed to attach to the mutated protein. At this point I am aware of 2 products currently undergoing human trials. One this the antibody alone, and from my understanding mainly just regulates production (I would guess similar to other cytoreductive agents (HU, Jakafi, etc)) but would likely not have the side-effects of lowered RBC, etc. as it is only attacking the specific CALR mutated cell. The second is the antibody that is also attached to another "killer" immune cell, that when attached to the CALR mutant cell will then kill the cell. This called a Bispecific Antibody (or you may see as a BiTE treatment = Bispecific T-cell Effector). From what I have seen, the first product (by Incyte) has a very high tolerance level and early results look good. The BiTE treatment should be more effective, possibly with greater potential side-effect risk (From Johnson & Johnson).

This is my best lay interpretation of these technologies. But, I will not claim to have all the details exactly correct - that is where you need to work with your specialist. For the phase 1 trial, I believe the number of patients is a total of 220 worldwide and for my trial site is a total of 9; so I would expect that the number at and center would be similar. What would be interesting to know would be the criteria that are used to determine final dosing. My final dose will be fairly low compared to another that I have has contact with. I only have ET, they have MF.

Hopefully once I get my dose settled in and "routine" maybe my symptom load (mostly severe fatigue) will go back a few years and my "normal" will be more enjoyable - as the song goes - "I'm much to young to feel so damn old"!!!

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@drbart86 Thanks! This sounds like the INCA033989 from Incyte? Again, many thanks for these updates. If we could, we would all be bringing you a hot dish and doing your dusting for you!

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Profile picture for nohrt4me (Jean) @nohrt4me

@drbart86 Thanks! This sounds like the INCA033989 from Incyte? Again, many thanks for these updates. If we could, we would all be bringing you a hot dish and doing your dusting for you!

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@nohrt4me no this is the Bispecfic T cell Effector (BiTE) ftom Johnson & Johnson. Incye is just the antibody. This a bit more info on it: https://ashpublications.org/blood/article/142/Supplement%201/1777/501436/Discovery-of-JNJ-88549968-a-Novel-First-in-Class

Here is a better description

Key Differences in Mechanism
• INCA033989 - A monoclonal antibody that selectively binds mutant CALR (mutCALR) on the cell surface, blocking the abnormal mutCALR-MPL complex. This turns off JAK-STAT signaling, reduces disease-driving gene transcription, and leads to outcomes like reduced proliferation, lower platelet overproduction, reduced megakaryocyte activity, and potential disease modification.
• JNJ-88549968: A bispecific T-cell redirecting antibody (BiTE-like, CALRmut x CD3). It acts as a bridge: one arm binds mutant CALR on the surface of malignant MPN cells (e.g., in CALR-mutated ET or MF), while the other engages CD3 on T cells. This redirects and activates T cells to kill the cancer cells directly (T-cell mediated cytotoxicity), rather than primarily blocking signaling.

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Profile picture for nohrt4me (Jean) @nohrt4me

@drbart86 Thanks! This sounds like the INCA033989 from Incyte? Again, many thanks for these updates. If we could, we would all be bringing you a hot dish and doing your dusting for you!

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@nohrt4me my wife would really appreciate the dusting!!!! 😀. Especially now as the dogs are blowing their coats 🐕🐕🐕
Thanks for the thoughts.

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Profile picture for Lori, Volunteer Mentor @loribmt

Hi @drbart86 Thank you for this update and your participation into this Clinical Trial for ET. Cancer research and development depends on these trials…along with the long awaiting cancer patients who would love to find a cure or remission from disease!
So far so good, as ‘they’ say, eh? I can relate to the mainlining of Benadryl! The best sleep I ever had. 😳 But also wired for hours later. LOL.

Sending positive vibes for smooth sailing with the next round. Keep us posted! Hugs.

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@loribmt update week 2 and early week 3.
Week 2 not much more than the increase in fatigue / lack of energy. I guess to be expected due to the huge engery burden that the immune system requires. Would walk in the hospital corridor from one end and back (1/4) and was tired.
This morning had 3rd dose. A big early to really tell, but had to rest on my corridor walk this evening. As well as a much slower pace. But it has been the day after that is the worst. Unless something strange happens remainder treatments in clinic every 3 weeks for up to 5 years.
Hoping fatigue will end at some point. Is a beautiful backpacking loop in the San Juan's (most beautiful part of CO) that I want to do again. But I think Everest is out of the picture 🤣 (not that it ever really was)

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Profile picture for drbart86 @drbart86

@loribmt update week 2 and early week 3.
Week 2 not much more than the increase in fatigue / lack of energy. I guess to be expected due to the huge engery burden that the immune system requires. Would walk in the hospital corridor from one end and back (1/4) and was tired.
This morning had 3rd dose. A big early to really tell, but had to rest on my corridor walk this evening. As well as a much slower pace. But it has been the day after that is the worst. Unless something strange happens remainder treatments in clinic every 3 weeks for up to 5 years.
Hoping fatigue will end at some point. Is a beautiful backpacking loop in the San Juan's (most beautiful part of CO) that I want to do again. But I think Everest is out of the picture 🤣 (not that it ever really was)

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@drbart86 We each have our own Everest! You don't need to go all the way around the world to find yours. A back-packing trip in the San Juans is a good goal.
Ginger

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