Full Press Release Details
Rigel Pharmaceuticals Provides Update on COVID-19
-- FDA declines to issue emergency use authorization
for fostamatinib for the treatment of COVID-19 in
hospitalized adults --
-- Rigel's COVID-19 program continues
to actively enroll patients and will provide a robust data set to
support the potential benefits of fostamatinib in COVID-19 --
SOUTH SAN FRANCISCO, Calif., August 13, 2021 - Rigel Pharmaceuticals,
Inc. (Nasdaq: RIGL), today announced that the U.S. Food and Drug Administration (FDA) has informed the Company that clinical data submitted
in late-May from a 59-patient NIH/NHLBI-sponsored Phase 2 trial of fostamatinib to treat hospitalized patients suffering from COVID-19
are insufficient for an emergency use authorization (EUA) at this time. The FDA noted in their response that they remain committed to
working with Rigel in the development of fostamatinib for COVID-19 as the Company is currently conducting a larger Phase 3 clinical trial
evaluating fostamatinib in hospitalized patients with COVID-19.
"With new virus variants spreading and vaccination rates plateauing,
there remains a need for therapies that can improve outcomes for hospitalized patients, particularly patients suffering from hyperinflammatory
COVID-19-related complications," said Raul Rodriguez, president and CEO of Rigel. "The Rigel team continues to focus on enrolling
our Phase 3 clinical trial, which we anticipate completing later this year, and we look forward to providing further safety and efficacy
data from this larger, 308-patient trial of fostamatinib in COVID-19 patients. If this trial meets its endpoints, we plan to resubmit
our EUA application with this additional data."
Fostamatinib Clinical Development Program in COVID-19
The broader clinical development program for fostamatinib is comprised
of three ongoing studies and a recently completed Phase 2 study. These studies are evaluating a wide range of hospitalized patients, including
those not on oxygen therapy, who are experiencing mild to severe COVID-19-related complications:
About COVID-19 & SYK Inhibition
COVID-19 is the infectious disease caused by Severe Acute Respiratory
Syndrome Coronavirus-2 (SARS-CoV-2). SARS-CoV-2 primarily infects the upper and lower respiratory tract and can lead to acute respiratory
distress syndrome (ARDS). Additionally, some patients develop other organ dysfunction including myocardial injury, acute kidney injury,
shock resulting in endothelial dysfunction and subsequently micro and macrovascular thrombosis.1 Much of the underlying
pathology of SARS-CoV-2 is thought to be secondary to a hyperinflammatory immune response associated with increased risk of thrombosis.2
Spleen tyrosine kinase (SYK) is involved in the intracellular signaling
pathways of many different immune cells. Therefore, SYK inhibition may improve outcomes in patients with COVID-19 via inhibition of key
Fc gamma receptor (Fc R) and c-type lectin receptor (CLR) mediated drivers of pathology such as pro-inflammatory cytokine release by
monocytes and macrophages, production of neutrophil extracellular traps (NETs) by neutrophils, and platelet aggregation.3,4,5,6 Furthermore,
SYK inhibition in neutrophils and platelets may lead to decreased thromboinflammation, alleviating organ dysfunction in critically
ill patients with COVID-19.
For more information on Rigel's comprehensive clinical program in
COVID-19, go to: https://www.rigel.com/pipeline/proprietary-programs/covid-19
Rigel Pharmaceuticals, Inc., is a biotechnology
company dedicated to discovering, developing and providing novel small molecule drugs that significantly improve the lives of patients
with hematologic disorders, cancer and rare immune diseases. Rigel's pioneering research focuses on signaling pathways that are critical
to disease mechanisms. The company's first FDA approved product is TAVALISSE (fostamatinib disodium hexahydrate)
tablets, the only oral spleen tyrosine kinase (SYK) inhibitor for the treatment of adult patients with chronic immune thrombocytopenia
who have had an insufficient response to a previous treatment. The product is also commercially available in Europe (TAVLESSE) and Canada
(TAVALISSE) for the treatment of chronic immune thrombocytopenia in adult patients.
Fostamatinib is currently being studied in a Phase 3 clinical trial
(NCT03764618) for the treatment of warm autoimmune hemolytic anemia (wAIHA)7; a Phase 3 clinical trial for the treatment
of hospitalized high-risk patients with COVID-197; an NIH/NHLBI-sponsored Phase 3 clinical trial (ACTIV-4 Host Tissue Trial)
for the treatment of COVID-19 in hospitalized patients, and a Phase 2 clinical trial for the treatment of COVID-19 being conducted by
Imperial College London.
Rigel's other clinical programs include its interleukin receptor-associated
kinase (IRAK) inhibitor program, and a receptor-interacting serine/threonine-protein kinase (RIP1) inhibitor program in clinical development
with partner Eli Lilly and Company. In addition, Rigel has product candidates in development with partners AstraZeneca, BerGenBio ASA,
Twitter or LinkedIn.
Please see www.TAVALISSE.com for the full Prescribing
1. Berlin DA, Gulick RM, and Martinez FJ. Severe Covid-19.
N Engl J Med 2020. DOI: https://doi.org/10.1056/NEJMcp2009575
2. Becker RC. COVID-19 Update: COVID-19 associated coagulopathy.
Journal of Thrombosis and Thrombolysis May 15, 2020. DOI: https://doi.org/10.1007/s11239-020-02134-3
3. Hoepel W et al. High titers and low fucosylation of early human anti-SARS-CoV-2 IgG
promote inflammation by alveolar macrophages. Science Translational Medicine 02 Jun 2021. DOI: https://www.doi.org/10.1126/scitranslmed.abf8654
4. Sung P-S and Hsieh S-L. CLEC2 and CLEC5A: Pathogenic Host Factors
in Acute Viral Infections. Frontiers in Immunology December 6, 2019. DOI: https://doi.org/10.3389/fimmu.2019.02867
5. Bye AP et al. Aberrant glycosylation of anti-SARS-CoV-2 IgG is a pro-thrombotic stimulus
platelets. BioRxiv March
26, 2021. DOI: https://doi.org/10.1101/2021.03.26.437014
6. Strich J et al. Fostamatinib
Inhibits Neutrophils Extracellular Traps Induced by COVID-19 Patient Plasma: A Potential Therapeutic. Journal of Infectious Disease
March 15, 2021. DOI: https://doi.org/10.1093/infdis/jiaa789
7. The product for this use or indication is investigational
and has not been proven safe or effective by any regulatory authority.
Forward-Looking Statements
This release contains forward-looking statements relating to, among
other things, Rigel's COVID-19 clinical program, including its use of fostamatinib to treat hospitalized patients suffering from
COVID-19; the clinical development program for fostamatinib, including the Rigel-led Phase 3 Trial, the Accelerating COVID-19 Therapeutic
Interventions and Vaccines (ACTIV) study and the Imperial College of London Investigator-Sponsored Trial; and Rigel's recently
completed Phase 2 study on fostamatinib. Any statements contained in this press release that are not statements of historical fact may
be deemed to be forward-looking statements. Words such as "potential", "may", "expects", and similar expressions
are intended to identify these forward-looking statements. These forward-looking statements are based on Rigel's current expectations
and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those
anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks
and uncertainties associated with the commercialization and marketing of TAVALISSE; risks that the FDA, EMA or other regulatory authorities
may make adverse decisions regarding fostamatinib; risks that TAVALISSE clinical trials may not be predictive of real-world results or
of results in subsequent clinical trials; risks that TAVALISSE may have unintended side effects, adverse reactions or incidents of misuses;
the availability of resources to develop Rigel's product candidates; market competition; as well as other risks detailed from time to
time in Rigel's reports filed with the Securities and Exchange Commission, including its Quarterly Report on Form 10-Q for the quarter
ended June 30, 2021. In addition, the COVID-19 pandemic may result in further delays in Rigel's studies, trials and sales, or impact
Rigel's ability to obtain supply of TAVALISSE. Rigel does not undertake any obligation to update forward-looking statements and expressly
disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein.
Contact for Investors & Media
Jodi Sievers - Rigel Pharmaceuticals