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Fostamatinib as a Single Agent or in Combination With Ruxolitinib for Treatment of Patients With Myelofibrosis With Severe Thrombocytopenia

Fostamatinib as a Single Agent or in Combination With Ruxolitinib for Treatment of Patients With Myelofibrosis With Severe Thrombocytopenia

Status
Terminated
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04543279
Enrollment
3
Registered
2020-09-10
Start date
2021-05-03
Completion date
2022-07-30
Last updated
2023-12-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Myelofibrosis, Thrombocytopenia

Brief summary

Fostamatinib may improve thrombocytopenia in myelofibrosis patients with severe thrombocytopenia (platelet \<50,000/microL) and allow them to initiate treatment with a JAK2 inhibitor, ruxolitinib. Additionally, fostamatinib monotherapy may also improve myelofibrosis related symptoms and splenomegaly.

Interventions

DRUGFostamatinib

Fostamatinib will be supplied by Rigel Pharmaceuticals.

DRUGRuxolitinib

Ruxolitinib is commercially available.

Sponsors

Rigel Pharmaceuticals
CollaboratorINDUSTRY
Washington University School of Medicine
Lead SponsorOTHER

Study design

Allocation
NON_RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Confirmed diagnosis of primary myelofibrosis or post-polycythemia vera/essential thrombocythemia myelofibrosis classified as high risk, intermediate-2 risk, or intermediate 1 risk by IPSS. * Severe thrombocytopenia defined as platelet count \< 50,000/microL (confirmed on at least two measurements over an 8-week period prior to start of study). * At least 18 years of age. * ECOG performance status ≤ 2 * Able to swallow pills * Adequate bone marrow and organ function as defined below: * ANC ≥ 1000/microL * Peripheral blood blasts ≤ 10% * Albumin \> 2.7 g/dL * Total bilirubin ≤ 1.5 x IULN; patients with Gilbert's syndrome may enroll if direct bilirubin ≤ 1.5 x IULN * AST(SGOT)/ALT(SGPT) ≤ 1.5 x IULN * Creatinine clearance \> 30 mL/min by Cockcroft-Gault * Female subjects must be either post-menopausal for at least 1 year or surgically sterile; or, if of childbearing potential, must not be pregnant or lactating and must agree to use a highly effective method of birth control throughout the duration of the trial and for 30 days following the last dose. Acceptable methods of birth control are defined as: hormonal contraception (pill, injection or implant) used consistently for at least 30 days prior to screening, an intrauterine device (IUD), or intrauterine hormone-releasing system (IUS), or true abstinence (i.e. abstinence is in line with the preferred and usual lifestyle of the subject.). Male subjects do not need to use contraception for fostamatinib because human studies showed minimal R406 in sperm. * Ability to understand and willingness to sign an IRB approved written informed consent document (or that of legally authorized representative, if applicable).

Exclusion criteria

* History of allogeneic stem cell transplant. * Any solid tumor or hematologic malignancy (other than myelofibrosis) requiring active treatment at the time of study entry * Currently receiving any other investigational agents. * A history of allergic reactions attributed to compounds of similar chemical or biologic composition to fostamatinib, ruxolitinib, or other agents used in the study. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable angina pectoris, or cardiac arrhythmia. * Subject has uncontrolled or poorly controlled hypertension, defined as systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg, whether or not the subject is receiving anti-hypertensive treatment. * Pregnant and/or breastfeeding. Women of childbearing potential must have a negative pregnancy test within 14 days of study entry and prior to the first dose of fostamatinib. * Known positive status for human immunodeficiency virus (HIV) * Chronic, active, or acute viral hepatitis A, B, or C infection, or hepatitis B or C carrier. * Treatment with strong CYP3A inhibitors or inducers within 14 days before the first dose of study drug. Strong CYP3A inhibitors and CYP3A inducers are not permitted during the study. * Ongoing gastrointestinal medical condition such as Crohn's disease, inflammatory bowel disease, or chronic diarrhea that is not well controlled and could interfere with absorption of oral medication or be exacerbated by study medication * Known hepatic cirrhosis or severe pre-existing hepatic impairment. * Uncontrolled coagulopathy or bleeding disorder. * Female patients who intend to donate eggs and male patients who intend to donate sperm during the course of this study or for 4 months after receiving the last dose of study treatment.

Design outcomes

Primary

MeasureTime frameDescription
Number of Participants With a Platelet Response (Part A)Week 12-Defined as an increase in platelet count ≥ 50K/microL with at least one more confirmatory platelet count separated by at least 2 weeks (in the absence of platelet transfusion) within the first 12 weeks of fostamatinib treatment
Toxicity of Fostamatinib and Ruxolitinib Treatment (Part B)From start of treatment through 30 days after last day of study treatment (estimated to be approximately 40 weeks)-Measured by number of adverse events, serious adverse events, and laboratory abnormalities

Secondary

MeasureTime frameDescription
Number of Participants Eligible to Initiate Therapy With Ruxolitinib (Part A)Through completion of fostamatinib treatment (12 weeks)
Toxicity of Fostamatinib Treatment (Part A)From start of treatment through 30 days after last day of study treatment (estimated to be approximately 16 weeks)-Measured by number of adverse events, serious adverse events, and laboratory abnormalities
Number of Participants Who Permanently Discontinue Fostamatinib Due to Fostamatinib Related Adverse Events (Part A)Through 12 weeks
Number of Participants Who Require Treatment Interruption of Fostamatinib Due to Adverse Events (Part A)Through 12 weeks
Number of Participants Who Was Dose Escalated and Tolerated Fostamatinib Dose Greater Than 100 mg BID (Part A)Through 12 weeks
Number of Participants Who Achieve 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)Week 12
Change in Mean Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)Week 12
Number of Participants With 50% or Greater Improvement in Myeloproliferative Neoplasm - Symptom Assessment Form Total Symptom Score (Part A) From Baseline to Week 12Baseline and Week 12-The Myeloproliferative Neoplasm - Symptom Assessment Form Total Symptom Score (MPN-SAF-TSS) has 10 questions for participants to rate their symptoms. The answers range from 0-absent to 10-worst imaginable. The total score for the questionnaire is 100. A higher score indicates worse symptoms.
Number of Participants Who Achieve Platelet Transfusion Independence (Part A)Through week 12
Number of Participants With Anemia Who Achieve RBC Transfusion Independence (Part A)Through week 12
Number of Participants With Change in Marrow Fibrosis by WHO Grading (Part A)Through week 12
Number of Participants With 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)12 weeks
Mean Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)12 weeks
Number of Participants With 50% or Greater Improvement in Total Symptom Score (Part B)12 weeks
Duration of Uninterrupted Ruxolitinib Treatment (Part B)Up to 36 weeks
Change in Marrow Fibrosis by WHO Grading (Part B)At completion of combination treatment (estimated to be 36 weeks)

Countries

United States

Participant flow

Participants by arm

ArmCount
Part A: Fostamatinib
The starting dose of fostamatinib is 100 mg twice daily (BID). After the first cycle, if no major dose related safety issue is observed and the platelet count is less than 50K/microL, then the fostamatinib dose will be increased to 150 mg BID for the next 2 cycles; otherwise the dose may be continued at 100 mg BID.
3
Part B: Fostamatinib + Ruxolitinib
After 3 cycles of fostamatinib monotherapy, all patients with a sustained platelet count ≥ 50K/microL, will continue on the current fostamatinib dose plus ruxolitinib at the recommended dose per standard prescribing guidelines for an additional 9 cycles. Patients who do not reach platelet count of at least 50K/microL but who achieve clinical benefit per the treating provider may continue on single agent fostamatinib for up to 12 total treatment cycles. If these patients achieve a sustained platelet count of ≥ 50K/microL at any point prior to Cycle 10 Day 1, then they may be eligible to enroll in Part B of the study and continue treatment with fostamatinib and ruxolitinib for the remainder of the study.
0
Total3

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyAdverse Event10
Overall StudyPhysician Decision10
Overall StudyWithdrawal by Subject10

Baseline characteristics

CharacteristicPart A: FostamatinibTotal
Age, Continuous68 years68 years
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants0 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
3 Participants3 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants
Race (NIH/OMB)
Asian
0 Participants0 Participants
Race (NIH/OMB)
Black or African American
0 Participants0 Participants
Race (NIH/OMB)
More than one race
0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants
Race (NIH/OMB)
White
3 Participants3 Participants
Region of Enrollment
United States
3 participants3 participants
Sex: Female, Male
Female
2 Participants2 Participants
Sex: Female, Male
Male
1 Participants1 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
1 / 30 / 0
other
Total, other adverse events
3 / 30 / 0
serious
Total, serious adverse events
2 / 30 / 0

Outcome results

Primary

Number of Participants With a Platelet Response (Part A)

-Defined as an increase in platelet count ≥ 50K/microL with at least one more confirmatory platelet count separated by at least 2 weeks (in the absence of platelet transfusion) within the first 12 weeks of fostamatinib treatment

Time frame: Week 12

Population: This outcome measure is only for Part A.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants With a Platelet Response (Part A)0 Participants
Primary

Toxicity of Fostamatinib and Ruxolitinib Treatment (Part B)

-Measured by number of adverse events, serious adverse events, and laboratory abnormalities

Time frame: From start of treatment through 30 days after last day of study treatment (estimated to be approximately 40 weeks)

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Change in Marrow Fibrosis by WHO Grading (Part B)

Time frame: At completion of combination treatment (estimated to be 36 weeks)

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Change in Mean Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)

Time frame: Week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (MEAN)Dispersion
Part A: FostamatinibChange in Mean Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)329.73 cm^3Standard Deviation 169.04
Secondary

Duration of Uninterrupted Ruxolitinib Treatment (Part B)

Time frame: Up to 36 weeks

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Mean Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)

Time frame: At completion of combination treatment (estimated to be 36 weeks)

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Mean Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)

Time frame: 12 weeks

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Number of Participants Eligible to Initiate Therapy With Ruxolitinib (Part A)

Time frame: Through completion of fostamatinib treatment (12 weeks)

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Eligible to Initiate Therapy With Ruxolitinib (Part A)0 Participants
Secondary

Number of Participants Who Achieve 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)

Time frame: Week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Who Achieve 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound at Week 12 of Fostamatinib Treatment (Part A)0 Participants
Secondary

Number of Participants Who Achieve Platelet Transfusion Independence (Part A)

Time frame: Through week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Who Achieve Platelet Transfusion Independence (Part A)0 Participants
Secondary

Number of Participants Who Permanently Discontinue Fostamatinib Due to Fostamatinib Related Adverse Events (Part A)

Time frame: Through 12 weeks

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Who Permanently Discontinue Fostamatinib Due to Fostamatinib Related Adverse Events (Part A)0 Participants
Secondary

Number of Participants Who Require Treatment Interruption of Fostamatinib Due to Adverse Events (Part A)

Time frame: Through 12 weeks

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Who Require Treatment Interruption of Fostamatinib Due to Adverse Events (Part A)1 Participants
Secondary

Number of Participants Who Was Dose Escalated and Tolerated Fostamatinib Dose Greater Than 100 mg BID (Part A)

Time frame: Through 12 weeks

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants Who Was Dose Escalated and Tolerated Fostamatinib Dose Greater Than 100 mg BID (Part A)2 Participants
Secondary

Number of Participants With 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)

Time frame: At completion of combination treatment (estimated to be 36 weeks)

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Number of Participants With 35% or Greater Reduction in Spleen Volume as Determined by Ultrasound After 12 Weeks of Combination Treatment (Part B)

Time frame: 12 weeks

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Number of Participants With 50% or Greater Improvement in Myeloproliferative Neoplasm - Symptom Assessment Form Total Symptom Score (Part A) From Baseline to Week 12

-The Myeloproliferative Neoplasm - Symptom Assessment Form Total Symptom Score (MPN-SAF-TSS) has 10 questions for participants to rate their symptoms. The answers range from 0-absent to 10-worst imaginable. The total score for the questionnaire is 100. A higher score indicates worse symptoms.

Time frame: Baseline and Week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants With 50% or Greater Improvement in Myeloproliferative Neoplasm - Symptom Assessment Form Total Symptom Score (Part A) From Baseline to Week 121 Participants
Secondary

Number of Participants With 50% or Greater Improvement in Total Symptom Score (Part B)

Time frame: 12 weeks

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Number of Participants With 50% or Greater Improvement in Total Symptom Score (Part B)

Time frame: At completion of combination treatment (estimated to be 36 weeks)

Population: No participants from Part A went on to receive treatment in Part B.

Secondary

Number of Participants With Anemia Who Achieve RBC Transfusion Independence (Part A)

Time frame: Through week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants With Anemia Who Achieve RBC Transfusion Independence (Part A)0 Participants
Secondary

Number of Participants With Change in Marrow Fibrosis by WHO Grading (Part A)

Time frame: Through week 12

Population: This outcome measure is for Part A only.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibNumber of Participants With Change in Marrow Fibrosis by WHO Grading (Part A)0 Participants
Secondary

Toxicity of Fostamatinib Treatment (Part A)

-Measured by number of adverse events, serious adverse events, and laboratory abnormalities

Time frame: From start of treatment through 30 days after last day of study treatment (estimated to be approximately 16 weeks)

Population: This outcome measure is for Part A only.

ArmMeasureGroupValue (COUNT_OF_PARTICIPANTS)
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 1 dyspnea1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 neutrophil count decreased1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 white blood cell decreased1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 fatigue1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 1 chills2 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 2 pain1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 1 fever1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 bacteremia1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 lung infection (pneumonia)1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 2 bruising1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 2 anorexia1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 joint pain secondary to arthritis1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 1 tendon cramps1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 3 neck pain1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 1 rash maculo-papular1 Participants
Part A: FostamatinibToxicity of Fostamatinib Treatment (Part A)Grade 2 hypertension1 Participants

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026