- ITP & PLATELET DISORDERS RESEARCH & TREATMENTS:
- GENERAL HEALTH & MEDICINE:
ITP & PLATELET DISORDERS RESEARCH & TREATMENTS
Recent news reports have raised everyone’s awareness of Zika virus and its alarming link with babies born with microcephaly (small heads). As the virus continues to spread, people who receive plasma protein therapies, like IVIg, are understandably concerned as to whether these therapies are safe to receive. Zika virus is a Flavavirus, mainly spread by Aedes mosquitos but also reported to be transmitted from mother to child, by transfusion with infected blood, and by sexual contact. The Plasma Protein Therapeutics Association (PPTA) is a trade association representing over 450 human plasma collection centers in North America and Europe. Its members produce about 80% of the plasma protein therapies in the US and 60% of those manufactured in Europe.
PPTA stated that their member companies have extensive experience with production processes that effectively eliminate Flavaviruses, if any were present in donated plasma. Therefore, Zika virus is not a concern for the safety of plasma protein therapies. PPTA said most Zika cases detected in Europe and the USA were acquired outside those geographical areas and there is almost a total absence of Zika infection in both the US and European plasma donor population. PPTA’s stringent donor screening procedures make it highly unlikely a person with signs of Zika infection would be allowed to donate plasma.
Zika virus is an intermediate sized virus (about 40 nm diameter), similar to other Flavaviruses (West Nile Virus, Dengue, Japanese Encephalitis, and Yellow Fever) because it has a lipid envelope. The large size and lipid envelope make the Zika virus susceptible to virus inactivation and removal steps that occur during the manufacturing process for plasma protein therapies. Used effectively on other Flavaviruses these steps include: solvent detergent, low pH incubation, caprylate, pasteurization or dry-heat treatment, and nanofiltration or fractionation.
PPTA is aware of recommendations by agencies and blood collection organizations, such as the American Red Cross, to defer potential donors of blood components from those who have traveled to areas considered at risk for Zika virus (Mexico, the Caribbean, and both Central and South America). However, because of absence of Zika virus in areas used for plasma sourcing (USA and Europe), the short-lived viral presence in the blood of those infected (usually about a week), and the effective processes for removing and inactivating viruses, PPTA does not consider deferral of plasma donors is warranted at this time.
“Zika Virus and Plasma Protein Therapies.” Plasma Protein Therapeutics Association (PPTA) Statement, Feb. 4, 2016.
FDA is reviewing its blood donor deferral policy related to spread of the Zika virus:
The American Red Cross issued a statement concerning deferral (for 28 days) of blood donors who have been to areas of South America and Caribbean with high levels of Zika.
The ITP treatment eltrombopag (Promacta®/Revolade®) worked well in real-life settings with more than 75% of the patients responding to the drug. Researchers from Spain in a retrospective study evaluated 164 chronic ITP patients from 40 Spanish centers who had been treated with eltrombopag. Median age of the 164 patients was 63 years old, and 72% of patients were women. The median time with an ITP diagnosis was 81 months. On average, patients had tried three other ITP therapies before trying eltrombopag.
Other pertinent findings:
- 45 patients (30%) were receiving other ITP treatments at the same time.
- 46 patients (30%) had bleeding symptoms the month before they began eltrombopag.
- 164 patient cohort had a median platelet count of 22,000/µL when started on eltrombopag.
- 135 patients (89%) achieved a platelet response; median time to response was 12 days.
- 123 patients (75%) maintained their response rate for 15 months after initiation of eltrombopag.
- 30 patients (18%) had adverse events, mostly mild or moderate events.
The study authors concluded that eltrombopag is highly effective and well tolerated in unselected patients with primary chronic ITP.
González-López TJ, Alvarez-Román MT, Pascual C, et al. “Eltrombopag safety and efficacy for primary chronic immune thrombocytopenia in clinical practice.” European Journal of Haematology, 2015 Dec 28. doi: 10.1111/ejh.12725. [Epub ahead of print].
If You Take Romiplostim (Nplate®) and It Stops Working, You May Have Developed Antibodies against Proteins in the Treatment
Thrombopoietin (TPO) is a glycoprotein hormone produced by the liver and kidney that regulates the production of platelets. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that bud off large numbers of platelets. So a thought might be that beating ITP might be easy. Doctors can just “pump up” the amount of thrombopoietin in an ITP patient’s body. Unfortunately, our human immune systems are extremely complex, and this approach does not work as one might have hoped. Specifically, studies on recombinant thrombopoietins were halted because a minority of patients developed an autoantibody that neutralized the recombinant thrombopoietin. Even worse was the fact that the autoantibodies cross reacted with and neutralized the body’s own endogenous TPO, resulting in thrombocytopenia. Therefore using thrombopoietin as an ITP medicine has not worked well. Instead doctors use thrombopoietin receptor agonists (TPO-RAs) such as romiplostim (Nplate®) and Eltrombopag (Promacta®). These products use the same pathways described above to pump up platelet production.
Unfortunately, it now appears that during long-term treatment, romiplostim (Nplate®) may bring about the development of neutralizing antibodies to the romiplostim, resulting in acute thrombocytopenia. A study done in Italy suggests that “response loss” doesn’t seem to be as rare as thought during romiplostim administration. The study showed that 28% of the patients on Nplate® developed autoantibodies against the drug. Switching to another TPO treatment helped some of them.
Carpenedo M, Cantoni S, Coccini V, Pogliani EM and Cairol R. “Response loss and development of neutralizing antibodies during long-term treatment with romiplostim in patients with immune thrombocytopenia: a case series.” European Journal of Haematology, December 31, 2015 issue.
GENERAL HEALTH & MEDICINE
Your mother always told you “eat your greens!” but now your ophthalmologist has a good reason to remind you too. Researchers at Harvard Medical School and Brigham & Women’s Hospital have found a link between reduced chances of contracting glaucoma, macular degeneration, and cataracts, with a nitrate-rich, leafy, green plant diet.
These debilitating eye diseases are known for their relationship to vision loss, and are indicated by pressure within the eye. Although the causes of these ocular issues vary, they are known within the ITP community as a side-effect from long-term steroid usage.
Physiologically, normal blood flow is hindered by glaucoma. The lining of the circulatory system, also known as vascular endothelium, controls blood flow, and is affected by nitrous oxide (NO) levels. Incidentally, leafy greens such as lettuce, celery, kale, collard greens, spinach, green beans, and beets, are rich in nitrate, and are converted to nitrous oxide in the digestive tract.
In a study on nitrate consumption in relation to glaucoma rates, researchers found that eating greater amounts of green vegetables correlated with a 50% reduced chance of contracting glaucoma. They also discovered important cardiovascular implications as well. Nitrates elevate oxygen levels in the blood, therefore thinning blood, decreasing blood pressure and preventing serious clotting. So whether you plan to combat potential side effects of steroids and improve your vision, or keep your blood pressure low, increasing your green veggie intake is one great way to do it!
Newman, Tim. Eating your greens may stave off glaucoma. 2015. MedLexicon International Ltd. Medical News Today. Bexhill-on-Sea, UK.