Rigel Reports Fourth Quarter and Full Year 2019 Financial Results and Provides Business Update Fourth quarter total revenues of $15.4 million; full year total revenues of $59.3 million Fourth quarter net product sales of

Rigel Reports Fourth Quarter and Full

Year 2019 Financial Results and Provides Business Update

Fourth quarter total revenues of $15.4

million; full year total revenues of $59.3 million

Fourth quarter net product sales of $13.8

million; full year net product sales of $43.8 million

Received $20.0 million payment from Grifols

in first quarter 2020 for European approval of fostamatinib in adult patients with chronic ITP

Conference call and webcast today at

SOUTH SAN FRANCISCO, Calif., February

27, 2020 /PRNewswire/ -- Rigel Pharmaceuticals, Inc. (Nasdaq:

RIGL) today reported financial results for the fourth quarter and full year ended December 31, 2019, 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.

are entering 2020 with a clear plan to drive shareholder value for Rigel," said Raul Rodriguez, Rigel's president and

CEO. "We see substantial opportunities for TAVALISSE to meet patient needs in the growing adult chronic ITP market, particularly

as an early line therapy. Utilization in these less refractory patients continues to grow with the support of ongoing physician

education and data generation. To expand the range of TAVALISSE indications, we are conducting a Phase 3 trial in warm AIHA and

expect to complete patient enrollment midyear. In addition, we are extremely excited about the potential of our early stage candidates

and are currently exploring partnership opportunities that would enable Rigel to realize near-term value while also participating

meaningfully in the upside of these programs."

At the 61st American Society

of Hematology (ASH) Annual Meeting & Exposition in December 2019, the company presented post-hoc data analysis from its Phase

3 clinical program of TAVALISSE in adult patients with chronic ITP. In this analysis, 32 patients received fostamatinib as a second-line

therapy, of which, 78% (25/32) achieved 1 platelet count of 50,000/ L (without rescue therapy). Adverse events were

manageable and consistent with those previously reported with fostamatinib. These data highlight the potential benefit of using

TAVALISSE in earlier lines of therapy.

In February 2020, Rigel received a

$20.0 million payment from its collaborative partner Grifols, S.A. (Grifols). The payment is comprised of $17.5 million for the

European Commission's approval of the marketing authorization application for fostamatinib for the treatment of chronic immune

thrombocytopenia in adult patients who are refractory to other treatments and a $2.5 million creditable advance royalty payment

based on the terms of the collaboration agreement. Fostamatinib will be marketed in Europe under the brand name TAVLESSE

(fostamatinib). Grifols is planning to launch the product in the second quarter of 2020.

Enrollment is ongoing in Rigel's Phase 3 pivotal trial

in warm AIHA, FORWARD (Fostamatinib Research in Warm Antibody AIHA Disease). A total of 34 patients have been randomized to date.

The trial remains on track to complete enrollment in mid-2020.

In February 2020, Rigel's partner Kissei Pharmaceuticals

Co., Ltd. (Kissei) was granted orphan drug designation from the Japanese Ministry of Health, Labour and Welfare for R788 (fostamatinib)

in chronic idiopathic thrombocytopenic purpura.

For the fourth quarter of 2019,

Rigel reported a net loss of $17.2 million, or $0.10 per share, compared to net income of $3.2 million, or $0.02 per share,

in the same period of 2018.

In the fourth quarter of 2019, total

revenues were $15.4 million, consisting of $13.8 million in net product sales and $1.6 million in contract revenues from collaborations.

Net product sales of $13.8 million increased by 90% compared to $7.3 million in the fourth quarter of 2018. This increase reflects

the expanding patient and prescriber base for TAVALISSE and the growing persistency rate for refills at month 4, which is approximately

Contract revenues from collaborations

of $1.6 million for the fourth quarter ended December 31, 2019 consists of a $1.5 million fee earned pursuant to an amendment of

the license and collaboration agreement with Aclaris Therapeutics, Inc. (Aclaris) in October 2019, as well as deferred revenue

from Rigel's collaboration with Grifols related to the performance of certain research and development services.

Rigel reported total costs and expenses

of $32.7 million in the fourth quarter of 2019, compared to $35.3 million for the same period in 2018. The decrease in costs and

expenses was primarily due to decreases in personnel-related expenses and various third-party costs.

For the full year ended December 31,

2019, Rigel reported a net loss of $66.9 million, or $0.40 per share, compared to a net loss of $70.5 million, or $0.44 per share,

for the same period of 2018.

Rigel reported total revenues of $59.3

million for the year ended December 31, 2019, consisting of $43.8 million in net product sales and $15.5 million in revenues related

to Rigel's collaboration agreements with Grifols, Kissei, Aclaris, and Impact Biomedicines, Inc.

Total costs and expenses for the year

ended December 31, 2019, were $128.4 million, compared to $117.2 million, for the same period of 2018. The increase in total costs

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

personnel-related costs, on-going commercialization of TAVALISSE in adult chronic ITP, and research and development costs related

to its Phase 1 study in RIP.

As of December 31, 2019, Rigel had

cash, cash equivalents and short-term investments of $98.1 million, compared to $128.5 million as of December 31, 2018. Rigel previously

announced that in September 2019, we entered into a $60.0 million term loan credit facility with MidCap Financial. At closing,

$10.0 million was funded to Rigel in

an initial tranche. The facility also gives Rigel the ability to access an additional $50.0 million, of which $40.0 million is

subject to the achievement of certain customary conditions.

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),

the immune system attacks and destroys the body's own blood platelets, which play an active role in blood clotting and healing.

Common symptoms of ITP are excessive bruising and bleeding. People suffering with chronic ITP may live with an increased risk of

severe bleeding events that can result in serious medical complications or even death. Current therapies for ITP include steroids,

blood platelet production boosters (TPO-RAs) and splenectomy. However, not all patients respond to existing therapies. As a result,

there remains a significant medical need for additional treatment options for patients with ITP.

Autoimmune hemolytic anemia (AIHA)

is a rare, serious blood disorder in which the immune system produces antibodies that result in the destruction of the body's own

red blood cells. AIHA affects approximately 45,000 adult patients in the U.S. and can be a severe, debilitating disease. To date,

there are no disease-targeted therapies approved for AIHA, despite the unmet medical need that exists for these patients. Warm

antibody AIHA (wAIHA), the most common form of AIHA, is characterized by the presence of antibodies that react with the red blood

cell surface at body temperature.

The investigational candidate, R835,

is an orally available, potent and selective inhibitor of IRAK1 and IRAK4 that has been shown preclinically to block inflammatory

cytokine production in response to toll-like receptor (TLR) and the interleukin-1 receptor (IL-1R) family signaling. TLRs and IL-1Rs

play a critical role in the innate immune response, and dysregulation of these pathways can lead to a variety of inflammatory pathological

conditions. R835 treatment demonstrates amelioration of clinical symptoms in multiple rodent models of inflammatory disease including

psoriasis, arthritis, lupus, multiple sclerosis and gout. The safety and efficacy of R835 has not been established by the FDA or

any healthcare authority.

The investigational candidate, R552,

is an orally available, potent and selective inhibitor of receptor-interacting protein kinase (RIP1). RIP1 is believed to play

a critical role in necroptosis. Necroptosis is a form of regulated cell death where the rupturing of cells leads to the dispersion