This section highlights FDA-related milestones and regulatory updates for drugs developed by Rigel Pharmaceuticals (RIGL).
Over the past two years, Rigel Pharmaceuticals has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
Gavreto, R289, REZLIDHIA®, and TAVALISSE. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
Gavreto (Pralsetinib) FDA Regulatory Events
Gavreto (Pralsetinib) is a drug developed by Rigel Pharmaceuticals for the following indication: Rearranged during transfection (RET) fusion-positive advanced Non-small cell lung cancer (NSCLC).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- Gavreto (Pralsetinib)
- Announced Date:
- March 31, 2026
- Indication:
- Rearranged during transfection (RET) fusion-positive advanced Non-small cell lung cancer (NSCLC)
Announcement
Rigel Pharmaceuticals, Inc announced publication of the final data from the Phase 1/2 ARROW study evaluating pralsetinib for the treatment of metastatic rearranged during transfection (RET) fusion-positive non-small cell lung cancer (NSCLC) in the Journal of Clinical Oncology.
AI Summary
Rigel Pharmaceuticals announced the publication of the final data from the Phase 1/2 ARROW study evaluating pralsetinib for the treatment of metastatic rearranged during transfection (RET) fusion–positive non‑small cell lung cancer in the Journal of Clinical Oncology. The report presents the complete trial results and summarizes patient outcomes across the study.
The final data showed that pralsetinib produced robust and durable responses in patients with RET fusion–positive NSCLC, with many patients experiencing meaningful tumor shrinkage and lasting benefit. The safety profile was described as manageable, with side effects that could be monitored and treated in routine oncology care. These findings reinforce the clinical advantages of selective RET inhibitors for this molecular subtype of lung cancer.
Publishing the final ARROW results gives clinicians and researchers important evidence supporting targeted treatment approaches and highlights the value of genetic testing to identify patients who may benefit from pralsetinib.
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R289 FDA Regulatory Timeline and Events
R289 is a drug developed by Rigel Pharmaceuticals for the following indication: For Lower-Risk MDS.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- R289
- Announced Date:
- December 7, 2025
- Indication:
- For Lower-Risk MDS
Announcement
Rigel Pharmaceuticals, Inc announced updated data from its ongoing Phase 1b study evaluating R2891, an oral prodrug of R835, a potent and selective dual inhibitor of interleukin receptor-associated kinases 1 and 4 (IRAK1/4), in patients with relapsed or refractory (R/R) lower-risk myelodysplastic syndrome (MDS).
AI Summary
Rigel reported updated Phase 1b data for R289, an oral prodrug of R835 that inhibits IRAK1/4, in 33 patients with relapsed or refractory lower‑risk MDS. The group was elderly (median age 75) and heavily pretreated (median 3 prior therapies). R289 was generally well tolerated across doses; common low‑grade side effects included diarrhea, constipation, fatigue, increased creatinine and cough. The most frequent serious events were anemia, low neutrophils, pneumonia and liver enzyme rises. One dose‑limiting toxicity occurred at 750 mg.
At doses ≥500 mg once daily, preliminary efficacy was seen: 6 of 18 (33%) evaluable transfusion‑dependent patients achieved red blood cell transfusion independence (RBC‑TI) >8 weeks, including 2 of 5 (40%) in the 500 mg twice‑daily group. Median time to RBC‑TI was 1.9 months and median RBC‑TI duration 22.9 weeks; some patients had hemoglobin rises of 2.9–6.1 g/dL. Steady‑state drug levels at ≥500 mg met targets for cytokine inhibition. Dose expansion is ongoing to select a Phase 2 dose in H2 2026.
Read Announcement- Drug:
- R289
- Announced Date:
- October 8, 2025
- Indication:
- For Lower-Risk MDS
Announcement
Rigel Pharmaceuticals, Inc nnounced the first patient has been enrolled in the dose expansion phase of the ongoing Phase 1b study of R2891 in patients with relapsed or refractory (R/R) lower-risk myelodysplastic syndrome (MDS).
AI Summary
Rigel Pharmaceuticals announced the first patient has been enrolled in the dose expansion phase of its Phase 1b study of R289 in patients with relapsed or refractory lower-risk myelodysplastic syndrome (MDS) who depend on blood transfusions. In this phase, 40 patients will be randomized to receive 500 mg of R289 once daily or 500 mg twice daily. The main goal is to select the recommended Phase 2 dose (RP2D) for future trials. R289 is a dual inhibitor of IRAK1/4 kinases, which may reduce inflammation in the bone marrow.
Completion of dose expansion will guide the planning of clinical studies. After the RP2D is chosen, an exploratory group of patients ineligible for erythropoiesis-stimulating agents will be treated at that dose. Rigel will share study results. Researchers hope R289 will offer a new treatment option for these patients.
Read Announcement- Drug:
- R289
- Announced Date:
- January 9, 2025
- Indication:
- For Lower-Risk MDS
Announcement
Rigel Pharmaceuticals, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug designation to R289 for the treatment of myelodysplastic syndromes (MDS).
AI Summary
Rigel Pharmaceuticals announced that the U.S. FDA has granted Orphan Drug designation to its drug candidate R289 for the treatment of myelodysplastic syndromes (MDS). This designation supports the development of R289, which is a selective dual inhibitor of IRAK1 and IRAK4. The drug is currently being evaluated in a Phase 1b clinical trial to assess its safety, tolerability, and early signs of effectiveness in patients with lower-risk MDS who have not responded to previous therapies.
The Orphan Drug designation is given to therapies intended for rare diseases affecting fewer than 200,000 people in the U.S., and it provides significant benefits. These benefits include tax credits, exemptions from certain FDA fees, and the possibility of having market exclusivity for seven years following approval. Rigel sees this as a major milestone in offering a promising new treatment option for MDS patients with substantial unmet needs.
Read Announcement- Drug:
- R289
- Announced Date:
- December 9, 2024
- Indication:
- For Lower-Risk MDS
Announcement
Rigel Pharmaceuticals, Inc announced initial data from its ongoing Phase 1b study evaluating R2891, an oral prodrug of R835, a potent and selective dual inhibitor of IRAK1 and IRAK4, in patients with relapsed or refractory (R/R) lower-risk myelodysplastic syndrome (LR-MDS).
AI Summary
Rigel Pharmaceuticals has shared early results from its ongoing Phase 1b study of R2891. R2891 is an oral prodrug of R835, a potent and selective dual inhibitor of IRAK1 and IRAK4. The drug is being tested in patients with relapsed or refractory lower-risk myelodysplastic syndrome (LR-MDS), a condition that has few treatment options, especially in elderly patients.
In the study, patients with a median age of 76 received R2891, and the results indicate that the drug is generally well tolerated. Among the transfusion-dependent patients taking doses of 500 mg or more once daily, 40% achieved hematologic responses, including red blood cell transfusion independence for extended periods. These findings offer promising evidence of R2891’s potential as a new treatment option for this challenging patient population.
Read Announcement- Drug:
- R289
- Announced Date:
- December 2, 2024
- Indication:
- For Lower-Risk MDS
Announcement
Rigel Pharmaceuticals, Inc announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to R289 for the treatment of patients with previously-treated transfusion dependent lower-risk myelodysplastic syndrome (LR-MDS). R2891, Rigel's potent and selective dual inhibitor of IRAK1 and IRAK4, is being studied in an ongoing Phase 1b study evaluating the safety, tolerability, pharmacokinetics and preliminary activity in patients with LR-MDS who are relapsed or refractory to prior therapies.
AI Summary
The U.S. Food and Drug Administration (FDA) has granted Fast Track designation to Rigel Pharmaceuticals’ R289 for treating patients with previously-treated, transfusion-dependent lower-risk myelodysplastic syndrome (LR-MDS). R289 is a potent and selective dual inhibitor of IRAK1 and IRAK4, and it targets inflammatory signaling that may drive the persistent cytopenias seen in these patients. This designation is based on promising early data from an ongoing Phase 1b study, which is evaluating the drug’s safety, tolerability, pharmacokinetics, and preliminary effectiveness in patients who have relapsed or are refractory to prior therapies.
Fast Track is meant to speed up the development and review process for drugs that address serious conditions with unmet medical needs. Rigel’s approach with R289 could potentially broaden treatment options for older patients with LR-MDS, offering renewed hope for improved management of this challenging disease.
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REZLIDHIA® (Olutasidenib) FDA Regulatory Timeline and Events
REZLIDHIA® (Olutasidenib) is a drug developed by Rigel Pharmaceuticals for the following indication: For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- REZLIDHIA® (Olutasidenib)
- Announced Date:
- November 17, 2025
- Indication:
- For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation
Announcement
Rigel Pharmaceuticals, Inc announced a peer-reviewed publication in the Journal of Hematology & Oncology of the final five-year data from the pivotal cohort of the Phase 2 registrational trial evaluating REZLIDHIA® (olutasidenib) for the treatment of patients with relapsed or refractory (R/R) mutant isocitrate dehydrogenase-1 (mIDH1) acute myeloid leukemia (AML).
AI Summary
Rigel Pharmaceuticals published final five‑year results from the pivotal Phase 2 registrational trial of olutasidenib in relapsed or refractory mIDH1 acute myeloid leukemia. The extended follow‑up confirmed durable responses and a manageable safety profile, with no new safety signals or cases of differentiation syndrome. Among 147 efficacy‑evaluable patients, 35% achieved complete remission or CR with partial hematologic recovery (median duration 25.3 months); overall response rate was 48% (median duration 15.5 months) and median overall survival was 11.5 months. About 39% of patients who needed red blood cell transfusions at baseline became transfusion‑independent.
Responses were often quick—66% responded within two months. Patients with one to two prior regimens had higher response rates and longer survival than those with three or more prior therapies. In 12 patients previously treated with venetoclax, 33% achieved CR/CRh and median overall survival was 16.2 months, with several ongoing remissions. Rigel also launched additional studies to evaluate olutasidenib in combination approaches.
Read Announcement- Drug:
- REZLIDHIA® (Olutasidenib)
- Announced Date:
- September 5, 2024
- Indication:
- For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation
Announcement
Rigel Pharmaceuticals, Inc announced the first patient has been enrolled in a Phase 1b/2 triplet therapy trial of decitabine and venetoclax in combination with REZLIDHIA® (olutasidenib) in patients with mutated isocitrate dehydrogenase-1 (mIDH1) acute myeloid leukemia (AML).
AI Summary
Rigel Pharmaceuticals, Inc. announced that the first patient has been enrolled in a Phase 1b/2 clinical trial combining decitabine and venetoclax with REZLIDHIA® (olutasidenib) for patients with mutated isocitrate dehydrogenase-1 (mIDH1) acute myeloid leukemia (AML). This triplet therapy trial aims to test the safety, tolerability, and appropriate dosing of this combination in patients with relapsed or refractory mIDH1 AML, as well as in newly diagnosed cases. The study is part of a multi-year strategic alliance with MD Anderson Cancer Center, which will help evaluate the treatment's potential to provide a new, all-oral option for patients. The trial plans to enroll around 60 participants, split evenly between newly diagnosed and relapsed or refractory patients, to assess the treatment's ability to achieve complete remission.
Read Announcement- Drug:
- REZLIDHIA® (Olutasidenib)
- Announced Date:
- June 14, 2024
- Indication:
- For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation
Announcement
Rigel Pharmaceuticals, Inc announced oral at the European Hematology Association (EHA) 2024 Hybrid Congress in Madrid, Spain being held June 13-16, 2024, and online.
AI Summary
Rigel Pharmaceuticals, Inc. announced that it will present new data at the European Hematology Association (EHA) 2024 Hybrid Congress in Madrid, Spain, from June 13-16, 2024, and online. The oral presentation will share final five-year efficacy results from the registrational Phase 2 trial of REZLIDHIA® (olutasidenib) in patients with relapsed or refractory mutated IDH1 (mIDH1) acute myeloid leukemia (AML). The study focused on heavily pretreated patients, including those who previously received venetoclax, and demonstrated rapid, durable responses along with a manageable safety profile. Dr. Jorge E. Cortes, a leading investigator, will highlight key outcomes such as transfusion independence, overall survival improvements, and sustained remissions. These results support the role of olutasidenib in addressing the unmet needs of patients with mIDH1 AML, offering a promising treatment option where few exist.
Read Announcement- Drug:
- REZLIDHIA® (Olutasidenib)
- Announced Date:
- June 14, 2024
- Indication:
- For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation
Announcement
Rigel Pharmaceuticals, Inc. announced four poster presentations at the European Hematology Association (EHA) 2024 Hybrid Congress in Madrid, Spain being held June 13-16, 2024, and online.
AI Summary
Rigel Pharmaceuticals, Inc. announced its participation in the European Hematology Association (EHA) 2024 Hybrid Congress in Madrid, Spain, from June 13-16, 2024, with online attendance available. The company will showcase one oral presentation and four poster presentations. In the oral session, Dr. Jorge E. Cortes will present the final five-year efficacy data from the registrational Phase 2 trial of REZLIDHIA® (olutasidenib) in heavily pretreated patients with relapsed/refractory mIDH1 acute myeloid leukemia (AML). This presentation will include key study results such as rates of transfusion independence and overall survival, with specific data on patients who had previously received venetoclax. The poster presentations will further explore the drug’s safety and efficacy in various subgroups, including elderly patients, those with AML secondary to myeloproliferative neoplasms, and patients using olutasidenib as a bridge to transplant.
Read Announcement- Drug:
- REZLIDHIA® (Olutasidenib)
- Announced Date:
- May 23, 2024
- Indication:
- For treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation
Announcement
Rigel Pharmaceuticals, Inc. announced upcoming presentations from their commercial and clinical-stage hematology and oncology portfolio at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting and European Hematology Association (EHA) 2024 Hybrid Congress. T
AI Summary
Rigel Pharmaceuticals, Inc. announced upcoming presentations at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting and the European Hematology Association (EHA) 2024 Hybrid Congress. These events will feature key data from their commercial and clinical-stage hematology and oncology portfolio. Among the highlights is new evidence on REZLIDHIA® (olutasidenib) for treating mutated isocitrate dehydrogenase-1 (mIDH1) acute myeloid leukemia (AML). The presentations will include five-year results from a registrational Phase 2 trial, reinforcing REZLIDHIA’s effectiveness in heavily pretreated R/R mIDH1 AML patients, including those who received prior venetoclax, as well as benefits observed in elderly, transplant-eligible, and post-myeloproliferative neoplasm patients.
The ASCO meeting will be held in Chicago from May 31 to June 4, 2024, and the EHA Congress in Madrid from June 13 to June 16, 2024, both available online and in person.
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TAVALISSE FDA Regulatory Events
TAVALISSE is a drug developed by Rigel Pharmaceuticals for the following indication: In Patients with Sickle Cell Disease.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- TAVALISSE
- Announced Date:
- March 27, 2025
- Indication:
- In Patients with Sickle Cell Disease
Announcement
Rigel Pharmaceuticals, Inc announced that it has entered into a settlement agreement with Annora Pharma Private Ltd., Hetero Labs Ltd., and Hetero USA, Inc. (collectively "Annora") resolving patent litigation related to Rigel's product TAVALISSE® (fostamatinib disodium hexahydrate).
AI Summary
Rigel Pharmaceuticals, Inc. has reached a settlement agreement with Annora Pharma Private Ltd., Hetero Labs Ltd., and Hetero USA, Inc. (collectively “Annora”) to resolve patent litigation surrounding its product TAVALISSE® (fostamatinib disodium hexahydrate). The dispute began when Annora filed an Abbreviated New Drug Application with the FDA, seeking approval for a generic version of TAVALISSE® in the United States. Under the terms of the agreement, Annora may begin selling its generic product as early as the second quarter of 2032, subject to certain conditions.
This settlement concludes all ongoing litigation between Rigel and Annora over the TAVALISSE® patents currently pending in New Jersey. Rigel’s leadership emphasized that the resolution reaffirms the strength of the company’s intellectual property protecting an important treatment for chronic immune thrombocytopenia.
Read Announcement- Drug:
- TAVALISSE
- Announced Date:
- January 22, 2025
- Indication:
- In Patients with Sickle Cell Disease
Announcement
Rigel Pharmaceuticals, Inc announced the first patient has been enrolled in a Phase 1 study evaluating the safety and tolerability of escalating doses of fostamatinib, the company's oral spleen tyrosine kinase (SYK) inhibitor, in patients with sickle cell disease (SCD).
AI Summary
Rigel Pharmaceuticals announced that the first patient has been enrolled in a Phase 1 study sponsored by the NIH/NHLBI. This study will test the safety and tolerability of increasing doses of fostamatinib, an oral spleen tyrosine kinase (SYK) inhibitor, in patients with sickle cell disease (SCD). The study aims to evaluate if fostamatinib can safely reduce complications caused by the abnormal shape of red blood cells in SCD, which often leads to painful episodes and serious health problems. Researchers will start patients on a lower dose and then increase it if the medicine is well-tolerated. As sickle cell disease is a lifelong condition with limited treatment options, this trial represents an important step in finding new ways to manage the disease. Rigel is committed to improving treatment and the quality of life for patients with hematologic disorders.
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