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PDSA E-News: November 28, 2017



Protalex Announces the Potential of PRTX-100 to Treat ITP

Protalex logoPDSA Medical Advisor John Semple, PhD, has led a successful investigation on the use of ITP Orphan Drug PRTX-100 in a mouse model, results of which have been recently published in the British Journal of Haematology. Dr. Semple’s data in “A highly purified form of Staphylococcal protein A alleviates murine immune thrombocytopenia” demonstrates that the drug developed by Protalex, Inc. increases platelet counts. The drug is a purified form of Staphylococcal protein A which modifies the immune system and has been previously reported on in the PDSA E-News.

Co-author of the study and Protalex’s Vice President, Richard Francovitch, PhD, explained that PRTX-100 is just as effective as IVIg in severely thrombocytopenic mice, working to limit the destruction of platelets. The therapy demonstrates a variety of immunomodulatory effects which prevent premature platelet destruction, supporting other preclinical benefits of the therapy as Protalex moves into additional phase 1 and 2 clinical trials.

Fields, Anne Marie. “Protalex Announces Publication in the British Journal of Haematology Supporting the Potential of PRTX-100 to Treat Immune Thrombocytopenia” Digital Journal. Oct 26 2017.

Immunomodulatory Treatments for Persistent and Chronic ITP

test tubesAlmost all ITP patients have received corticosteroids such as prednisone, prednisolone, or dexamethasone, but in reality 15 to 40% of patients with persistent or chronic primary ITP are intolerant to the treatment. A systematic review of 28 studies on MEDLINE was performed to elucidate the efficacy of immunomodulatory drugs Dapsone, INF-alpha, Danazol, and Hydroxychloroquine as a second-line therapy to steroids in ITP.

On average, patients who had received immunomodulatory drugs were 50 years old, 47% had been splenectomized, and 70% were female. “Overall response” and “complete response” were defined achieving a platelet count greater than 30,000, and 100,000, respectively. Over half of patients achieved an overall response as a result of treatment with Dapsone, Danazol, and Hydroxychloroquine and are recommended for patients with high risk of infection or low risk of bleeding. Dapsone and Hydroxychloroquine are recommended for patients with antinuclear antibodies (symptoms of an active autoimmune disease). Patients experienced some side effects with Danazol (73%), Dapsone (51%), and INF-alpha (30%); side effects were not noted in patients who were treated with Hydroxychloroquine.

Weber et. al. “Immunomodulatory treatments for persistent and chronic immune thrombocytopenic purpura: A PRISMA-compliant systematic review and meta-analysis of 28 studies.” Medicine (Baltimore). 2017 Sep;96(37).

Long-Term Eltrombopag Increases Platelet Counts, Decreases Bleeding in ITP

PromactaFinal results of a multi-year study of long-term use of Eltrombopag were recently published in Blood last month. Studies have already demonstrated that treatment with the TPO-receptor agonist for less than six months at a time effectively elevates platelet counts and reduces bleeding in patients with ITP. Researchers from seven different medical institutions around the world examined the effect of Eltrombopag as a second-line therapy for chronic ITP patients when treated for more than a half-year.

Researchers treated 302 patients who had been diagnosed with ITP for more than six months and had already received some sort of treatment for their disease. The patients were started on a dose of 50mg Eltrombopag daily and doses were altered accordingly. The median treatment was 2.37 years; 45% of patients completed the study and one fourth of patients enrolled in the trial continued Eltrombopag for 4 or more years. Patients increased their platelet count over 50,000 by the second week of therapy; 86% of patients elevated their platelet count to 50,000 at least once and 52% of study patients kept their platelet counts above 50,000 for over 25 weeks. Bleeding symptoms decreased among the study population from 57% to 16% after one year of treatment. Patients who had extremely low platelet counts at baseline, a greater number of previous therapies, and had been splenectomized were less likely to respond as robustly to treatment. These findings are an exciting step forward for patients who require long-term use of a safe and effective ITP therapy.

Wong, R. S., Saleh, M. N., Khelif, A., Salama, A., Portella, M. S., Burgess, P., & Bussel, J. B. (2017). Safety and efficacy of long-term treatment of chronic/persistent ITP with eltrombopag: final results of the EXTEND study. Blood.


FDA Approves First Test for Detecting Zika in Blood Donations

mosquitoThe US Food and Drug Administration has taken a huge step forward in screening blood donations for Zika virus. While not applicable to individual diagnosis of infection with Zika virus, the new “cobas Zika test” tests donated plasma from whole blood and blood components using a nucleic acid test that identifies the presence of genetic information from the Zika virus. Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research expressed, “Screening blood donations for the Zika virus is critical to preventing infected donations from entering the US blood supply. Today’s approval is the result of a commitment by the manufacturer to work rapidly and collaboratively with the FDA and the blood collection industry to respond to a public health crisis and ensure the safety of blood in the US and its territories.” The FDA had previously issued a rule that demanded all states screen blood for Zika, but the new Cobas Test is the first to effectively screen blood donors with a specificity of 99%.

Staff. “FDA approves first test for detecting Zika in blood donations.” Hematology Times. Oct 6 2017.



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