Research and Markets: Rigel/AstraZeneca's R788 (fostamatinib) - an oral Syk inhibitor for rheumatoid arthritis

DUBLIN--()--Research and Markets ( has announced the addition of the "Rigel/AstraZeneca's R788 (fostamatinib) - an oral Syk inhibitor for rheumatoid arthritis" report to their offering.

Rigel and AstraZeneca's R788 is in phase III trials for rheumatoid arthritis (RA). R788 is an oral, small molecule that modulates inflammation via inhibition of splenic tyrosine kinase (Syk). The companies have reported data from all three phase II TASKi trials and have begun their phase III OSKIRA trial program. Of special interest, the TASKi3 trial results differed from those of the TASKi 1 and 2 trials. This report explores the possible reasons for that discrepancy and the implications relative to the outcome of the ongoing phase III trials. It also discusses emerging safety signals, the degree to which the program measures up to FDA guidance for the development of RA therapies, and the market potential.

Key Topics Covered:



1. Rheumatoid Arthritis

2. Splenic tyrosine kinase (Syk) has many roles in health and disease

3. Rigel's R788



1. Phase I trials

2. TASKi 1 (Treatment of Arthritis with Syk Kinase Inhibition 1)

- Efficacy

- Safety

3. TASKi 2

4. TASKi 3

5. Other indications

6. The phase III program


1. Efficacy data were favorable in TASKi 1 and 2

2. TASKi 3 failed, begging for explanations as to why those results differed

- Differing entrance criteria

- Demographic imbalances at baseline

- Erythrocyte Sedimentation Rate (ESR) vs C-reactive protein (CRP) entrance criteria

- Geographic and regional differences

- What about differences in placebo response rates across trials?

3. Putting it all together, what are the implications for phase III trials?

4. Current data provide reasonable insight into the likely safety profile, but phase III and ultimately post-market data may be needed to fully assess risk.

- Basic tolerability

- More significant safety concerns are associated with Syk inhibition

- Generic effects of immunosuppression and comparisons to competitors

- In summary

5. The regulatory pathway is well demarcated


1. Initially, R788 will compete against several approved agents

2. Products in late stage development


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Research and Markets
Laura Wood, Senior Manager.
U.S. Fax: 646-607-1907
Fax (outside U.S.): +353-1-481-1716
Sector: Pharmaceuticals


Research and Markets
Laura Wood, Senior Manager.
U.S. Fax: 646-607-1907
Fax (outside U.S.): +353-1-481-1716
Sector: Pharmaceuticals