Safety and Efficacy of Eltrombopag at Escalated Doses
| Status: | Active, not recruiting |
|---|---|
| Conditions: | Infectious Disease, Hematology |
| Therapuetic Areas: | Hematology, Immunology / Infectious Diseases |
| Healthy: | No |
| Age Range: | 12 - Any |
| Updated: | 4/17/2018 |
| Start Date: | February 2013 |
| End Date: | March 30, 2019 |
Safety and Efficacy of Eltrombopag at Escalated Doses up to 150mg in Patients With Persistent and Chronic Immune Thrombocytopenia (ITP) Not Responsive to 75 mg
Study rationale is based on the data that in previous clinical studies of eltrombopag in ITP
there are some patients who have been reported as non responders at the maximal approved dose
of 75 mg daily. The trend in both normal volunteers and in patients with ITP suggest and
increasing response rate with increased doses of eltrombopag up to a dose of 75mg. Previously
published data has shown no overt increase in toxicity in normal volunteers, oncology
patients and aplastic anemia patients treated with escalated doses as high or higher than
those proposed in this study.
It therefore seems possible that in ITP patients who did not respond to a dose of 75mg daily,
eltrombopag could be more effective at a higher dose. We propose a double blind randomized
controlled trial in ITP patients who have been defined as non-responders at the maximum dose
(75mg) of eltrombopag, assessing efficacy and toxicity at higher daily doses (100mg, 125 mg,
150 mg)
there are some patients who have been reported as non responders at the maximal approved dose
of 75 mg daily. The trend in both normal volunteers and in patients with ITP suggest and
increasing response rate with increased doses of eltrombopag up to a dose of 75mg. Previously
published data has shown no overt increase in toxicity in normal volunteers, oncology
patients and aplastic anemia patients treated with escalated doses as high or higher than
those proposed in this study.
It therefore seems possible that in ITP patients who did not respond to a dose of 75mg daily,
eltrombopag could be more effective at a higher dose. We propose a double blind randomized
controlled trial in ITP patients who have been defined as non-responders at the maximum dose
(75mg) of eltrombopag, assessing efficacy and toxicity at higher daily doses (100mg, 125 mg,
150 mg)
Preliminary data in pediatric patients (who seem to metabolize eltrombopag differently
especially at younger ages) find that in the middle and lowest age cohort, even doses of 75
mg were often insufficient to obtain a response.
Altogether, this data suggest both that a higher dose in ITP may be more efficacious in
increasing the platelet count and that there is no overt increase in toxicity in normal
volunteers, oncology patients and aplastic anemia patients treated with doses as high or
higher than those proposed in this study.
Double-blind, randomized, placebo-controlled trial in subjects with ITP who are
'non-responders' at the maximum package insert dose (75mg) of eltrombopag; non-responders are
those with platelet counts < 50,000 despite taking 75 mg/day of eltrombopag for at least 3
weeks.
Study Design (First part): 8 Weeks
Subjects will be randomly allocated in a two to one ratio to receive treatment or placebo.
All subjects in the study will receive 75 mg eltrombopag and then be randomized to receive
either an additional 25 mg of eltrombopag or matching placebo tablet dispensed by the
research pharmacy. Subjects and investigators will be blinded to randomization. Randomization
will be stratified according to splenectomy status. Randomization will be performed at the
time of informed consent with a computer generated randomization table. Subjects and
investigators will be blinded to assignment and treatment in this phase. Eltrombopag will be
administered for 8 weeks or until the platelet count exceeds 100,000; at this point dosing
will stop, subject will be considered a responder and the subject will eligible for entering
Part 2 (the long term treatment part of the study) if desired and agreed to be appropriate by
the subject giving consent, and the treating physician. The dose at which the subject
achieved the primary endpoint (> 50,000 and increase by > 20,000) will be considered the dose
of response. Even if a patient achieves a response, if the platelet counts remains < 100,000,
then the dose escalation schema in the figure above will continue.
Dose escalation will continue, despite satisfaction of the primary endpoint of study (>
50,000 and > 20,000 above baseline), unless the platelet count reaches 100,000. The rationale
for this approach is to maximize clinically relevant responses for the subjects and
standardize data for analysis. Subjects will stop study medication if the platelet count is
within the normal range, thereby minimizing any safety risk associated with elevated platelet
count. By continuing to dose escalate subjects until the platelet count is > 100,000, the
maximum response and correlation of dose will be tracked allowing better understanding of
sustained response and dose-dependent response, which can be applied to future consideration
dosage for periods of short-term hemostasis ( i.e surgical procedures). The 8 weeks of data
collected in enrolled subjects on the standardized protocol will have the balance of
consistency of dosage and unequivocality of response while maintaining subject safety.
Enrollment will be stratified to address concerns regarding the inclusion of pediatric
subjects. Enrollment will begin with adult subjects ≥ 18 years of age, until there is safety
information available for review from at least three adult patients who received active
therapy for 8 weeks with exposure to the maximal proposed dose of 150 mg. After review of
this unblinded safety information by independent Data Safety Monitoring Officer (DMSO) we
will allow pediatric patients 12-18 years of age to enroll on the protocol.
Long Term Treatment Extension (Part 2): (18 months)
After 8 weeks or once dosing is stopped because the platelet count is > 100,000, the subject
will be unblinded, once the data forms are complete with the assistance of the research
pharmacy.
Subjects who received and responded to eltrombopag higher dose treatment will have the option
to continue therapy with periodic monitoring and ongoing dose adjustment.
Subject who had a platelet count > 100,000 can enter Part 2 at the dose at which the subject
met primary response criteria after the platelet count decreases to < 100,000/uL
(microliters) on serial monitoring in the immediate post-study monitoring period.
Subjects randomized to the placebo group who did not respond will have the opportunity to
receive open label escalated dose eltrombopag over 8 weeks following the study protocol as if
they had been randomized to active drug in the study. This group will provide the
"confirmatory group" to see if the rate of response in the randomized group can be confirmed
in this group.
Consent will be obtained for additional monitoring with bone marrow aspirate and biopsy at 1
year and additional ophthalmologic examinations at 6 months and 18 months.
The trial will have an 80% statistical power at the 5% level of significance (two sided) to
detect a difference in the proportion of subjects receiving increased dose of eltrombopag
with a primary response (2 consecutive platelet counts of > 50,000 and an increase of >
20,000 from the study baseline with in the 8 week increased dose window not as a result of
rescue treatment ) to subjects without a primary response in the placebo group assuming 50%
of subjects randomized to active drug will have a response and 5% of subjects randomized to
placebo would have a response. However an interim analysis would be performed after 18
subjects to test for futility and efficacy and also to re-estimate sample size. If neither
futility or efficacy are met the trial would continue to enroll. Based on the observed
treatment effect at the interim analysis the sample size would be allowed to expand to up to
60 subjects.
Dose modification will be made on the basis of individual platelet response as detailed below
to a maximal dose of 150mg.
especially at younger ages) find that in the middle and lowest age cohort, even doses of 75
mg were often insufficient to obtain a response.
Altogether, this data suggest both that a higher dose in ITP may be more efficacious in
increasing the platelet count and that there is no overt increase in toxicity in normal
volunteers, oncology patients and aplastic anemia patients treated with doses as high or
higher than those proposed in this study.
Double-blind, randomized, placebo-controlled trial in subjects with ITP who are
'non-responders' at the maximum package insert dose (75mg) of eltrombopag; non-responders are
those with platelet counts < 50,000 despite taking 75 mg/day of eltrombopag for at least 3
weeks.
Study Design (First part): 8 Weeks
Subjects will be randomly allocated in a two to one ratio to receive treatment or placebo.
All subjects in the study will receive 75 mg eltrombopag and then be randomized to receive
either an additional 25 mg of eltrombopag or matching placebo tablet dispensed by the
research pharmacy. Subjects and investigators will be blinded to randomization. Randomization
will be stratified according to splenectomy status. Randomization will be performed at the
time of informed consent with a computer generated randomization table. Subjects and
investigators will be blinded to assignment and treatment in this phase. Eltrombopag will be
administered for 8 weeks or until the platelet count exceeds 100,000; at this point dosing
will stop, subject will be considered a responder and the subject will eligible for entering
Part 2 (the long term treatment part of the study) if desired and agreed to be appropriate by
the subject giving consent, and the treating physician. The dose at which the subject
achieved the primary endpoint (> 50,000 and increase by > 20,000) will be considered the dose
of response. Even if a patient achieves a response, if the platelet counts remains < 100,000,
then the dose escalation schema in the figure above will continue.
Dose escalation will continue, despite satisfaction of the primary endpoint of study (>
50,000 and > 20,000 above baseline), unless the platelet count reaches 100,000. The rationale
for this approach is to maximize clinically relevant responses for the subjects and
standardize data for analysis. Subjects will stop study medication if the platelet count is
within the normal range, thereby minimizing any safety risk associated with elevated platelet
count. By continuing to dose escalate subjects until the platelet count is > 100,000, the
maximum response and correlation of dose will be tracked allowing better understanding of
sustained response and dose-dependent response, which can be applied to future consideration
dosage for periods of short-term hemostasis ( i.e surgical procedures). The 8 weeks of data
collected in enrolled subjects on the standardized protocol will have the balance of
consistency of dosage and unequivocality of response while maintaining subject safety.
Enrollment will be stratified to address concerns regarding the inclusion of pediatric
subjects. Enrollment will begin with adult subjects ≥ 18 years of age, until there is safety
information available for review from at least three adult patients who received active
therapy for 8 weeks with exposure to the maximal proposed dose of 150 mg. After review of
this unblinded safety information by independent Data Safety Monitoring Officer (DMSO) we
will allow pediatric patients 12-18 years of age to enroll on the protocol.
Long Term Treatment Extension (Part 2): (18 months)
After 8 weeks or once dosing is stopped because the platelet count is > 100,000, the subject
will be unblinded, once the data forms are complete with the assistance of the research
pharmacy.
Subjects who received and responded to eltrombopag higher dose treatment will have the option
to continue therapy with periodic monitoring and ongoing dose adjustment.
Subject who had a platelet count > 100,000 can enter Part 2 at the dose at which the subject
met primary response criteria after the platelet count decreases to < 100,000/uL
(microliters) on serial monitoring in the immediate post-study monitoring period.
Subjects randomized to the placebo group who did not respond will have the opportunity to
receive open label escalated dose eltrombopag over 8 weeks following the study protocol as if
they had been randomized to active drug in the study. This group will provide the
"confirmatory group" to see if the rate of response in the randomized group can be confirmed
in this group.
Consent will be obtained for additional monitoring with bone marrow aspirate and biopsy at 1
year and additional ophthalmologic examinations at 6 months and 18 months.
The trial will have an 80% statistical power at the 5% level of significance (two sided) to
detect a difference in the proportion of subjects receiving increased dose of eltrombopag
with a primary response (2 consecutive platelet counts of > 50,000 and an increase of >
20,000 from the study baseline with in the 8 week increased dose window not as a result of
rescue treatment ) to subjects without a primary response in the placebo group assuming 50%
of subjects randomized to active drug will have a response and 5% of subjects randomized to
placebo would have a response. However an interim analysis would be performed after 18
subjects to test for futility and efficacy and also to re-estimate sample size. If neither
futility or efficacy are met the trial would continue to enroll. Based on the observed
treatment effect at the interim analysis the sample size would be allowed to expand to up to
60 subjects.
Dose modification will be made on the basis of individual platelet response as detailed below
to a maximal dose of 150mg.
Inclusion Criteria:
- Subject or their parent/ guardian has signed and dated a written informed consent
- Male and Females aged 12 years or older diagnosed with chronic ITP according to the
new consensus guidelines
- No indication of a disease which may cause thrombocytopenia other than ITP----no
specific testing required
- Subjects with thrombocytopenia ≤ 50,000 /uL after at least 21 days of daily dosage
with eltrombopag 75mg
- Stable dosage of concomitant treatments for ITP
≥ 2 weeks or longer (corticosteroids);
- At least 2 weeks from rescue therapy for ITP (WinRho, Intravenous Immunoglobulin
(IVIG), corticosteroids, platelet transfusion)
- At least 4 weeks from rituximab treatment
- Pregnant or Lactating Women are excluded
- Women of child-bearing age with a negative pregnancy test within 7 days of enrollment
and who agree to use acceptable methods of birth control will be eligible for this
study
- Female subjects or female partners of male subjects must either be of non-child
bearing potential (hysterectomy, bilateral ovariectomy, bilateral tubal ligation or
post menopausal for more than one year) OR, if of child bearing potential, using one
of the following highly effective methods of contraception.
- complete abstinence from intercourse
- Intrauterine device (IUD)
- Two forms of barrier contraception. diaphragm plus spermicide, or for males condoms
plus spermicide.
- Male partner is sterile and is the only partner of the female.
- Systemic contraceptives (combined oral progesterone only)
Exclusion Criteria:
- Previous history of eltrombopag-related liver function test (LFT) elevation that
required interruption of treatment
- Previous history of immediate or delayed hypersensitivity reaction or idiosyncrasy to
drugs chemically related to eltrombopag
- HIV Infection
- History of Arterial of Venous Thrombosis within the past year or requiring ongoing
therapy
- Active Hepatitis C infection
- Treatment with medications that affect platelet function ( including but not limited
to Aspirin, Clopidogrel and /or NSAIDs) or anti-coagulant medications
- Elevated Aspartate Aminotransferase(AST/ALT) or Creatinine > 1.5 times upper limit of
normal in 4 weeks prior to enrollment*
- Abnormalities in white blood cell count (WBC), automatic neutrophil count (ANC), and
Hemoglobin > 1.5 times upper or lower limit of normal*
- * Subjects can be rescreened to be included
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