Clinical trial design

The fostamatinib in ITP (FIT) clinical programme (FIT-1, FIT-2 and FIT-3) was designed to evaluate Tavlesse efficacy, safety and durability1, 2, *

Fostamatinib in ITP (FIT) clinical trial design diagram including; trial length, chronic ITP patients participating and treatment response.

Adapted from Bussel J, et al., 2018

All patients with platelets < 50,000 /μL, regardless of treatment arm, were eligible to enter FIT-3 (open-label extension) at or after week 121. In the FIT clinical trials, stable concurrent ITP therapy was allowed, and rescue therapy was permitted if needed. Visits at which rescue medication was used were excluded from the efficacy analysis3, 4, ‡

Patient characteristics

The FIT programme included adult patients with chronic ITP who had received ≥ 1 prior treatment option1

The FIT programme characteristics illustrate a difficult-to-treat population with long-standing ITP, many attempts at prior therapy for ITPs, and an average platelet count at baseline that is typically associated with bleeding episodes.1

Selected baseline patient characteristics in FIT-1 and FIT-21, 3, 4

Median time since diagnosis

8.5 years

Median age

54 years


61% female; 39% male

Median platelet count

16,000 /μL

Platelet counts < 15,000 /μL


Splenectomy (time since splenectomy)

35% (all > 6 months, except for 1 patient)

Prior treatment exposure among patients in FIT-1 and FIT-21, 3, 4

Median number of prior therapies












Tavlesse dosing

  • Tavlesse starting dose of one 100 mg tablet BID3, 4
  • Based on platelet count and tolerability, the dose could be increased to one 150 mg tablet BID at or after week 43, 4 
  • Patients who had a platelet count of ≥ 50,000 /μL at the time of rollover to the FIT-3 open-label extension study maintained their existing dose of Tavlesse2

To read more on Tavlesse dosing, please click here.

ITP: immune thrombocytopenia


  1. Bussel J, Arnold D, Grossbard E, et al. Fostamatinib for the treatment of adult persistent and chronic immune thrombocytopenia: results of two phase 3, randomized, placebo-controlled trials. Am J Hematol. 2018;93(7):921-930
  2. Bussel JB, Arnold DM, Boxer MA, et al. Long-term fostamatinib treatment of adults with immune thrombocytopenia during the phase 3 clinical trial program. Am J Hematol. 2019;94(5):546-553
  3. Tavlesse Summary of Product Characteristics. Great Britain. Grifols. Date of revision: January 2021. Available at . Accessed on 14/2/2022.
  4. Tavlesse Summary of Product Characteristics. Northern Ireland. Grifols. Date of revision: August 2021. Available at Accessed on 14/2/2022