# Fostamatinib

Source: https://onco.cc/drugs/fostamatinib/  
OnCo record `fostamatinib` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Fostamatinib is a tablet that blocks the enzyme SYK so the spleen stops destroying antibody-coated platelets; it is approved for chronic immune thrombocytopenia and was first trialled as a lymphoma drug.

## Summary

Fostamatinib is an oral SYK inhibitor approved in the United States in 2018 for adults with chronic immune thrombocytopenia (ITP) who have not responded to a previous treatment. SYK sits downstream of the B-cell receptor and of Fc receptors, and fostamatinib was originally studied in B-cell lymphomas and chronic lymphocytic leukaemia, where responses were modest and the programme moved to autoimmune disease. Its place in cancer care is therefore supportive: managing immune-mediated low platelets, including in patients whose ITP accompanies lymphoid cancers. Hypertension, diarrhoea and raised liver enzymes are the main side effects.

## Fields

- Kind: Treatment
- Status: established
- Last checked: 2026-09-08
- Also known as: Fostamatinib Disodium; R788; R935788
- Tags: gap-fill; supportive-care
- Brand: Tavalisse
- Modality: Oral spleen tyrosine kinase (SYK) inhibitor
- Mechanism: A prodrug converted to R406, which inhibits SYK and so blocks the antibody-triggered destruction of platelets by macrophages in the spleen.
- Approvals: US 2018: Chronic immune thrombocytopenia in adults with insufficient response to a previous treatment

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Fostamatinib
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=fostamatinib
- Drugs@FDA NDA 209299: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=209299

## Connected records

- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/)
- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- terms: [Thrombocytopenia](https://onco.cc/terms/thrombocytopenia/)

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