Low-dose drug combo may be effective treatment for ITP
Eltrombopag-prednisone combination controls platelet levels in small trial
Combining low-dose eltrombopag with reduced-dose prednisone may be an effective approach for controlling immune thrombocytopenia (ITP) while minimizing the risk of medication side effects, a small clinical trial showed.
The findings were detailed in the study, “Reduced dose prednisone plus eltrombopag for the treatment of newly diagnosed adult primary immune thrombocytopenia: A prospective, multicentre, phase 2 clinical trial,” published as a letter to the editor in the British Journal of Haematology.
ITP is a rare disorder where the immune system attacks and destroys platelets, which are small cell fragments that help blood clot, putting patients at an increased risk of bleeding.
Corticosteroids are immune-suppressing medicines often used as a first-line treatment to control ITP. But using high doses of corticosteroids for a long time often causes problematic side effects, so it’s recommended that doses be tapered as low as possible within the first few weeks of treatment. Although tapering corticosteroid doses in this way can help prevent side effects, it may increase the risk of disease relapse.
Eltrombopag, sold as Promacta and Alvaiz in the U.S., is a thrombopoietin receptor agonist, a type of medication that works to increase platelet production in the body. It is generally used as a second-line treatment for ITP in patients who haven’t responded well to first-line treatments like corticosteroids.
Maintaining platelet levels while tapering medication dose
Scientists in China conducted a small Phase 2 clinical trial (ChiCTR2200058259) to assess whether combining low-dose eltrombopag with a reduced-corticosteroid regimen could control ITP while minimizing the need for corticosteroids to reduce the risk of side effects.
The study participants all started on a reduced dose of the corticosteroid prednisone. They received an initial weight-based dose for three weeks; then the dose was gradually reduced to 5 mg/day or lower by study week eight. At the same time, participants were given a low dose of eltrombopag (25 mg/day), which could be tapered starting at study week eight if platelet levels stayed high. In total, treatment lasted 20 weeks (about five months).
The study’s primary goal was to determine the proportion of patients who were able to maintain platelet levels of at least 50 billion platelets per liter of blood while reducing their prednisone dose to lower than 5 mg/day within the first eight weeks, as planned. Out of the 22 newly diagnosed ITP patients who completed the 20-week treatment protocol, all but one met the primary endpoint, and most were able to discontinue prednisone entirely within the first eight weeks.
The study’s secondary goal was to assess the proportion of patients who were able to maintain high platelet levels with an eltrombopag dose no higher than 25 mg twice weekly by week 20. Of the 22 participants who completed the treatment period, 12 met this endpoint.
Safety data showed that “all patients tolerated treatment well,” the researchers wrote, and no serious side effects were reported. Quality of life data also indicated that patients tended to report improvements in mental health after starting on treatment, which suggests “that rapid [platelet] stabilization and reduced treatment burden may positively affect psychosocial well-being,” the researchers wrote.
Long-term follow-up data, with a median follow-up time of nearly two years, were available for 17 patients. Only three of these patients experienced a relapse (a recurrence of low platelet levels).
Overall, “the combination of [reduced-dose prednisone and low-dose eltrombopag] appeared to produce a rapid and durable response in [newly-diagnosed] ITP patients and partially improved quality of life, suggesting it could potentially represent a viable first-line treatment option,” the researchers concluded, though they stressed that this was a small study and additional research will be needed to validate the findings.
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