Interferon, another ET chemo

Patients taking pegylated Interferon
often do so by giving themselves
subcutaneous injections at home.

While Hydrea (hydroxyurea) remains go-to drug for ET, some patients are taking Interferon, which has been a known platelet reducer since the 1990s. It still seems to be an experimental drug; studies of ET patients and Interferon have been small and have not yet covered long-term effects.

Here's what I've been able to find out about it:

There are two types of Interferon, alpha and pegylated. Pegylated Interferon stays in the body longer and seems to be more effective and have fewer side-effects.

A study in 1993 (before the three ET mutations were discovered), 51 German MPN  patients (26 of whom had ET) participated in a limited study. All patients in the study experienced reduced platelet counts, 78 percent of them lower than 450, which is the upper level of the "normal" range established by the World Health Organization.

Forty of the MPN patients were treated for more than three months with Interferon. Ten of those patients discontinued used within the first year or so because they could not tolerate side effects: nausea, fatigue, dizziness, fever, headache, diarrhea, weight loss, heartburn, hair loss, bone pain, and anemia. However, the study concluded that for younger patients, especially those with a history of thrombosis, Interferon treatment should be considered, and most research in the 1990s called the drug "promising.



Fast forward to 2011, and another study in Blood Journal. That research showed that Interferon was not associated with fetal abnormalities, important for women in child-bearing years, and that it was not associated with leukemia. The jury is still out on whether Hydrea is a cause of ET "morphing" into full blown leukemia, but the finding that Interferon was not associated with higher leukemia levels was considered good.

This study also showed that Interferon is tolerated less well by older patients and it remains unclear whether Interferon actually lowers the rate of thrombosis, even though it does seem to lower platelets. (FWIW, this article is worth slogging through for lots of really good info, though it is full of medical terms you might have to look up.)

In 2014, Interferon treatment was studied specifically in JAK2-positive patients and reported in the journal Haematologica. Pegylated Interferon showed less toxicity than Interferon alpha, and it worked between 75 and 95 percent of the time to reduce platelet counts.

Remarkably, in 15-20 percent of JAK2 patients, no mutation could be found following treatment.

However, an equal number of patients in the group (15-20 percent) could not tolerate the side effects of Interferon Alpha:

The serious side-effects associated with IFN-α [Interferon Alpha] use include an increased risk of depression, exacerbation of autoimmune diseases, neuropathy, hypothyroidism, retinitis, and reversible left heart failure. Long-term toxicity data on patients being treated with pegylated IFN-α beyond two years are not available.

Despite the tantalizing finding that some patients' genetic mutations seemed to disappear, researchers were not ready to say that these patients had been cured or that their longevity/quality of life had improved.

Also in 2014, The New England Journal of Medicine reported that two patients who were CALR positive went into what seemed to be complete remission after about three years of Interferon treatment.

Remission lasted 18 months in one patient, five years in another.

One was placed on Interferon immediately after diagnosis, the other was placed on Interferon after he had grown resistant to Hydrea. During Interferon treatment the patients reported fatigue and mood changes, which stopped after the Interferon was discontinued. Study showed that the Interferon seemed to target the mutation process in these patients. But, again, the long-term benefits of Interferon are still not known.

Despite some tantalizing successes, Interferon seems to be a treatment with some debilitating side effects, and remissions have not so far been declared cures. Trials on Interferon are ongoing, and we need to salute the brave souls willing to participate in this research.

If you have had experience with Interferon, we would like to hear from you! Please comment here or on our FB page.

Be well!

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