This week, I was started on Pegasys to treat my Essential Thrombocythemia.  Several people have asked me, “so, what is Pegasys?”  Well, I was wondering, too, so I’ve been doing some reading and researching.  I’ve had a little trouble finding MPD specific information about Pegasys, because it is commonly used to treat Hepatitis.  Only recently has it started being used for MPDs.  So, a lot of the information that I’ve been finding deals with using Pegasys in conjunction with other Hepatitis drugs.  But, I was able to find information that I felt could be applied to MPDs and I would like to share it with all of you.

Pegasys is simply a common brand name for Pegylated Interferon.  Many of us are familiar with Interferon, maybe not through use but at least from hearing about it from our Hematologist.

Interferon is normally the drug of choice for pregnant MPD patients, younger patients, in special cases, or when another drug (for example, Hydroxyurea or Anagrelide) is not tolerated by the patient.  Interferon controls blood cell count (red cells, white cells and platelets), it reduces spleen size and it reduces clotting events.  It also may reduce fibrosis (scarring in the bone marrow) and it may reduce MPD-related itching.

So, what is the difference between Pegylated Interferon (Pegasys) and Interferon?  Well, it turns out that the answer is pretty simple.  The difference is the PEG in PEGylated.  PEG stands for Polyethylene Glycol.  When the PEG molecule is combined with the Interferon, it lowers Interferon’s toxicity and it slows the clearance of the drug from the blood stream, making is a longer acting, slow releasing medicine.  That means that you get the benefits of Interferon, plus the PEG allows for weekly injections, rather than several injections a week.  It also allows fewer side effects than with non-pegylated Interferon.

Now, that doesn’t mean that there are no side-effects when starting Pegasys.  If you read my last post, you know that flu-like aches, pains and chills, headache, extreme fatigue, fever, heavy thirst and loss of appetite are common (and were present for me).  However, it was explained to me by both my local Hematologist and the nurse at the Mayo Clinic that the side-effects will lessen with each dose.  Just like when you get the flu, your body will create a resistance to the side-effects, and that resistance will increase with each exposure (dose).  Eventually, the side-effects will be non-existent.

I think what excites me the most about Pegasys, even more than the possibility of reducing my clotting events and some of my symptoms, is the possibility that Pegylated Interferon may reduce abnormal JAK2 in patients, possibly leading to remission.  Isn’t that exciting?!?  However, trials are still being done to test this possibility.  I know, those are a lot of ‘possibilities’, and no ‘promises’, but it is still a positive outlook.

Pegasys does have a website, HERE.  However, please keep this in mind when perusing the site: again, most information available on Pegasys deals with using the drug to treat Hepatitis.  This means that many of the warnings offered are for when Pegasys is used in conjunction with another drug (for example, Copegus).  Therefore, many of those warnings and information do not apply to us (for example, Interferon is used to treat MPD patients who are pregnant.  However, Interferon and Copegus used together are dangerous to pregnant women).  PLEASE…if you are looking for information on Pegasys (or anything related to our treatment, really), please make sure the situation applies, correctly and completely, to us.


~ by julie70 on January 28, 2011.

8 Responses to “Pegasys”

  1. Wow….I hope the side-effects get to be non-existent sooner that you think…My prayers are with you.

  2. I am starting tomorrow, also am suppose to get 50 Mmg but here I can only buy 135 Mmg doses, which makes the treatment very expensive if I can’t use the remaining for the next week.
    can you kindly share your experience?
    best regards,

    • Hi Paulo,
      I get frustrated, too, that I have to buy more than I need. Thankfully, my insurance covers most of the cost, but I still feel like I am wasting so much medication. It’s too bad they don’t make them in smaller amounts, or that we can’t get pre-filled syringes for our specific dose. Too bad we can’t network with other patients and our doctor and share the medication with someone else! I would happily give the remainder of mine to someone who could not afford it, if I could do so safely and legally.

      • Hi Julie,
        Thank you very much for your comment and advise.
        I am now taking the full 135 mg and at least for some more time I am not wasting it.
        As I am doing rather well and I am lucky to not suffer any side effects, soon my doctors plan to reduce the dose and to increase the interval between treatments and … surprise I got from them the informal information that if well handled and kept in the refrigerator I can actually use the amount I need and re-use the rest.

      • Ah…that’s very interesting that they said that. Something to ask my doctor about, for sure :).
        How often are you receiving a dose now?

      • I do for now 135 mg a week

      • Hi Paulo,
        Did you start out on that dose, or did your doctor work you up to it? How is the Pegasys working for you?

      • Hi Julie,
        I started x 50 Mgr and my doctor increased it up to 135 Mgr week. I expect to now do 135 Mgr every 10 days or 2 weeks.

        I worked so well that I did a bone puncheon and they did find the jak 2…
        only my “hematocrite” is higher than normal, platelets are around 400 000

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