Rigel Reports Second Quarter 2020 Financial Results, Provides Business Update, and Overviews COVID-19 Program Second quarter net product sales of $15.0 million, a year-over-year increase of 47% University of Amsterdam in

Rigel Reports Second Quarter 2020 Financial

Results, Provides Business Update, and

Overviews COVID-19 Program

Second quarter net product

sales of $15.0 million, a year-over-year increase of 47%

University of Amsterdam in

vitro studies showed fostamatinib blocked macrophage hyper-

inflammatory response to serum from severe COVID-19 patients

Appointed 30-year industry

veteran David Santos as Chief Commercial Officer

Conference call and webcast today at

SOUTH SAN FRANCISCO, Calif., August

4, 2020 /PRNewswire/ -- Rigel Pharmaceuticals, Inc. (Nasdaq:

RIGL) today reported financial results for the second quarter ended June 30, 2020, including sales of TAVALISSE (fostamatinib

disodium hexahydrate) tablets, for the treatment of adults with chronic immune thrombocytopenia (ITP) who have had an insufficient

response to a previous treatment.

"During the second quarter we

achieved significant progress across all aspects of our business, despite the challenges resulting from the COVID-19 pandemic,"

said Raul Rodriguez, Rigel's president and CEO. "Sales of TAVALISSE increased during the quarter and in July, the product

became available in initial European markets. We continued to advance our pipeline, most recently with the launch of an investigator-sponsored

trial in COVID-19 pneumonia. We believe there is clear scientific rationale to explore the potential of SYK-inhibition to treat

these patients and possibly prevent severe respiratory conditions resulting from COVID-19. We will continue to pursue opportunities

to expand these efforts."

COVID-19 Program Highlights

Rigel announced a Phase 2 investigator-sponsored

trial (IST) with Imperial College London to evaluate the efficacy of fostamatinib for the treatment of COVID-19 pneumonia. The

IST is a two-stage, open label, controlled clinical trial with patients randomized (1:1:1) to fostamatinib, ruxolitinib, or standard

of care. Treatment will be administered twice daily for 14 days and patients will receive a follow-up assessment at day 14 and

day 28 after the first dose. The primary objective will be to determine the efficacy of fostamatinib and the efficacy of ruxolitinib

compared to standard of care to reduce the proportion of hospitalized patients progressing from mild or moderate to severe COVID-19

pneumonia. Rigel will provide support for this trial along with Novartis.

Recent in vitro studies led by the Amsterdam University

Medical Center at the University of Amsterdam, showed that R406, the active metabolite of fostamatinib, blocked macrophage

hyperinflammatory responses to a combination of immune complexes formed by anti-Spike IgG in serum from severe COVID-19

patients. Anti-Spike IgG levels are known to correlate with the severity of COVID-19. These results suggest that by

inhibiting anti-Spike IgG-mediated hyperinflammation, R406 could potentially play a role in the prevention of cytokine storms

as well as pulmonary edema and thrombosis associated with severe COVID-19.1 In addition, researchers at The Broad

Institute of the Massachusetts Institute of Technology (MIT) and Harvard led a recent screen to identify FDA-approved

compounds that reduce mucin-1 (MUC1) protein abundance. MUC1 is a biomarker used to predict the development of ALI and ARDS

and correlates with poor clinical outcomes. Of the 3,713 compounds that were screened, fostamatinib was the only compound

identified which both decreased expression of MUC1 and is FDA approved. Fostamatinib demonstrated preferential depletion of

MUC1 from epithelial cells without affecting cell viability. The research was focused on drug repurposing for the much lower

risk of toxicity and the ability of FDA-approved treatments to be delivered on a shortened timescale, which is critical for

patients afflicted with lung disease resulting from COVID-19.2

Post-hoc data analysis from Rigel's previous Phase 3 clinical

program of TAVALISSE in adult patients with chronic ITP, which highlights the potential benefit of use in earlier lines of therapy,

was published in the British Journal of Haematology. Inclusion in one of the leading peer-reviewed journals in the field

of hematology underscores the significance of the 78% (25/32) response rate, defined as at least 1 platelet count of at least 50,000/ L,

when TAVALISSE was used as a second-line therapy in Rigel's Phase 3 clinical program. Adverse events were manageable and

consistent with those previously reported with fostamatinib. Rigel's field teams are sharing this analysis with physicians.

Grifols S.A., Rigel's collaborator

in Europe, launched fostamatinib disodium hexahydrate in Germany and the United Kingdom in July, under the European brand name

TAVLESSE. TAVLESSE is indicated in Europe for the treatment of chronic ITP in adult patients who are refractory to other treatments.

Clinical trial sites in Rigel's

FORWARD study, a Phase 3 pivotal trial of TAVALISSE in warm autoimmune hemolytic anemia (wAIHA), are now mostly open and enrolling

patients after a temporary postponement due to the COVID-19 pandemic. Currently, the FORWARD study has enrolled 44 of the 90 patients

targeted for enrollment and has over 90 active clinical trial sites established across 22 countries with incremental sites being

At the European League Against Rheumatism (EULAR) 2020 E-Congress

in June, Rigel presented two oral and two poster presentations highlighting its investigational compound R835, a potent and selective

inhibitor of both interleukin receptor associated kinase (IRAK)1 and IRAK4. In multiple pre-clinical rodent models of acute and

chronic inflammation, R835 administration resulted in reduced inflammation, and in Phase 1 human studies it showed encouraging

pharmacokinetic properties.

Rigel has appointed Dave Santos as

executive vice president and chief commercial officer. Mr. Santos joins Rigel with over 30 years of commercial experience in the

biopharmaceutical industry with companies such as Bristol-Myers Squibb, Lilly, Genentech, and most recently Jazz Pharmaceuticals,

where he led the Hematology/Oncology Business Unit. He has a robust track record in sales and marketing leadership roles, building

commercial capabilities, and growing brands in the hematology-oncology area, where he has spent most of his career.

For the second quarter of 2020, Rigel

reported a net loss of $17.6 million, or $0.10 per share, compared to a net loss of $20.6 million, $0.12 per share, in the same

In the second quarter of 2020, total

revenues were $16.0 million, consisting of $15.0 million in net product sales and $1.0 million in contract revenues from collaborations.

Net product sales increased by 47% from $10.2 million in the second quarter of 2019.

Rigel reported total costs and expenses

of $33.4 million in the second quarter of 2020, compared to $31.7 million for the same period in 2019. The increase in total costs

and expenses was primarily due to the increase in third-party costs related to Rigel's ongoing pivotal Phase 3 study in warm AIHA,

research and development costs related to other clinical programs and personnel-related costs, partially offset by stock-based

compensation expense.

For the six months ended June 30, 2020,

Rigel reported net income of $3.7 million, or $0.02 per share, compared to a net loss of $38.2 million, or $0.23 per share, in

the same period of 2019.

Rigel reported total revenues of $71.8

million for the six months ended June 30, 2020, compared to $23.0 million for the same period in 2019. Total revenues for the six

months ended June 30, 2020 consisted of $27.7 million in net product sales and $44.1 million in revenues related to Rigel's

collaboration agreement with Grifols. Total revenues for the six months June 30, 2019 consisted of $18.2 million in net product

sales and $4.8 million in revenues related to Rigel's collaboration agreements with Grifols and Kissei.

Total costs and expenses for the six

months ended June 30, 2020 were $68.1 million, compared to $62.7 million, for the same period of 2019. The increase in total costs

and expenses was primarily related to the research and development cost for its ongoing pivotal Phase 3 study in warm AIHA and

research and development costs related to other clinical programs, partially offset by stock-based compensation expense.

As of June 30, 2020, Rigel had cash,

cash equivalents and short-term investments of $92.5 million, compared to $98.1 million as of December 31, 2019.

Conference Call and Webcast with

Slides Today at 4:30pm Eastern Time

Rigel will hold a live conference call

and webcast today at 4:30pm Eastern Time (1:30pm Pacific Time).

Participants can access the live conference

call by dialing (877) 407-3088 (domestic) or (201) 389-0927 (international). The conference call and accompanying slides will also

be webcast live and can be accessed from the Investor Relations section of the company's website at www.rigel.com. The webcast

will be archived and available for replay after the call via the Rigel website.

In patients with ITP (immune thrombocytopenia),