Coronavirus (COVID-19) Update
AmerisourceBergen and our global businesses are highly engaged during the ongoing spread of the novel COVID-19 “Coronavirus."

June 18, 2018

US Bioservices selected by Rigel Pharmaceuticals, Inc. to dispense TAVALISSE™ (fostamatinib disodium hexahydrate) Tablets

Frisco, Texas – US Bioservices, a specialty pharmacy that is a part of AmerisourceBergen, announced today it has been selected by Rigel Pharmaceuticals to dispense TAVALISSE™ (fostamatinib disodium hexahydrate) Tablets. TAVALISSE™ was approved by the U.S. Food and Drug Administration on April 17, 2018 for the treatment of adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment. ITP is a rare blood disorder in which the immune system attacks and destroys platelets in the blood.

ITP impacts approximately 65,000 adult patients in the U.S. The disorder can be characterized by excessive bruising and bleeding due to abnormally low platelet counts. Many adult patients with ITP develop the chronic form of the disease that requires more specialized disease management and continued follow-up care with a hematologist. Rigel Pharmaceuticals’ fostamatinib ITP program was developed to treat chronic ITP, targeting an underlying autoimmune cause of the disease through inhibiting the SYK pathway.

“Adult patients with rare and orphan diseases like chronic ITP often require highly targeted and specialized therapy. This is especially true for chronic ITP patients who had an inadequate response to previous treatment, requiring specialized care,” said Kelly Ratliff, President of US Bioservices. “US Bioservices’ unmatched experience in rare disease, hematology and oncology allows us to apply a unique, clinically-coordinated approach that specifically supports the needs of the smallest patient populations in their communities.”

US Bioservices’ multidisciplinary teams are organized to develop long-standing, collaborative relationships with hematologists and oncologists in order to deliver more integrated care for patients and caregivers. In addition to US Bioservices, AmerisourceBergen companies – ASD Healthcare, Oncology Supply and ION Solutions – will respectively support specialty distribution to health systems and hematology and community oncology practices for the launch of TAVALISSE™. Whether a patient presents for care in a health system or community prescriber’s office, patients will be able to fill their prescriptions at their preferred point of care. This concerted approach will strategically and geographically increase the accessibility of TAVALISSE™ for patients and allow for a seamless transition to US Bioservices pharmacy dispensing. 

TAVALISSE™ is a limited distribution medication that is available from select specialty pharmacies. Physicians may submit prescriptions to US Bioservices via phone (855.751.7953), fax (888.418.7246), ePrescribe or the MyPathpoint Prescriber Portal.

Important Safety Information
Warnings and Precautions

  • Hypertension can occur with TAVALISSE treatment. Patients with pre-existing hypertension may be more susceptible to the hypertensive effects. Monitor blood pressure every 2 weeks until stable, then monthly, and adjust or initiate antihypertensive therapy for blood pressure control maintenance during therapy. If increased blood pressure persists, TAVALISSE interruption, reduction, or discontinuation may be required.
  • Elevated liver function tests (LFTs), mainly ALT and AST, can occur with TAVALISSE. Monitor LFTs monthly during treatment. If ALT or AST increase to >3 x upper limit of normal, manage hepatotoxicity using TAVALISSE interruption, reduction, or discontinuation.

  • Diarrhea occurred in 31% of patients and severe diarrhea occurred in 1% of patients treated with TAVALISSE. Monitor patients for the development of diarrhea and manage using supportive care measures early after the onset of symptoms. If diarrhea becomes severe (≥Grade 3), interrupt, reduce dose or discontinue TAVALISSE.

  • Neutropenia occurred in 6% of patients treated with TAVALISSE; febrile neutropenia occurred in 1% of patients. Monitor the ANC monthly and for infection during treatment. Manage toxicity with TAVALISSE interruption, reduction, or discontinuation.
  • TAVALISSE can cause fetal harm when administered to pregnant women. Advise pregnant women the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 1 month after the last dose. Verify pregnancy status prior to initiating TAVALISSE. It is unknown if TAVALISSE or its metabolite is present in human milk. Because of the potential for serious adverse reactions in a breastfed child, advise a lactating woman not to breastfeed during TAVALISSE treatment and for at least 1 month after the last dose.

Drug Interactions
Concomitant use of TAVALISSE with strong CYP3A4 inhibitors increases exposure to the major active metabolite of TAVALISSE (R406), which may increase the risk of adverse reactions. Monitor for toxicities that may require a reduction in TAVALISSE dose.
It is not recommended to use TAVALISSE with strong CYP3A4 inducers, as concomitant use reduces exposure to R406.
Concomitant use of TAVALISSE may increase concentrations of some CYP3A4 substrate drugs and may require a dose reduction of the CYP3A4 substrate drug.

Concomitant use of TAVALISSE may increase concentrations of BCRP substrate drugs (eg, rosuvastatin) and P-Glycoprotein (P-gp) substrate drugs (eg, digoxin), which may require a dose reduction of the BCRP and P-gp substrate drug.

Adverse Reactions
Serious adverse drug reactions in the ITP double-blind studies were febrile neutropenia, diarrhea, pneumonia, and hypertensive crisis, which occurred in 1% of TAVALISSE patients. In addition, severe adverse reactions occurred including dyspnea and hypertension (both 2%), neutropenia, arthralgia, chest pain, diarrhea, dizziness, nephrolithiasis, pain in extremity, toothache, syncope, and hypoxia (all 1%).
Common adverse reactions (≥5% and more common than placebo) from FIT-1 and FIT-2 included: diarrhea, hypertension, nausea, dizziness, ALT and AST increased, respiratory infection, rash, abdominal pain, fatigue, chest pain, and neutropenia.

For more information including full prescribing information and important safety information, please visit

1  Accessed June 1, 2018. 


About AmerisourceBergen                 
AmerisourceBergen provides pharmaceutical products, value-driving services and business solutions that improve access to care. Tens of thousands of healthcare providers, veterinary practices and livestock producers trust us as their partner in the pharmaceutical supply chain. Global manufacturers depend on us for services that drive commercial success for their products. Through our daily work—and powered by our 21,000 associates—we are united in our responsibility to create healthier futures. AmerisourceBergen is ranked #12 on the Fortune 500, with more than $150 billion in annual revenue. The company is headquartered in Valley Forge, PA and has a presence in 50+ countries. Learn more at