Open-Label Study to Evaluate the Safety and Efficacy of Avatrombopag and Remission Rates in Adults With ITP of ≤6 Months

A Multicenter, Open-Label Study to Evaluate the Safety and Efficacy of Avatrombopag and Remission Rates in Adults With Immune Thrombocytopenia (ITP) of ≤6 Months Duration

This study will evaluate the safety and efficacy of avatrombopag in subjects with a confirmed diagnosis of primary ITP (≤6 months duration) over 26 weeks of treatment, and also evaluate the incidence of ITP remission.

Study Overview

• Status: Withdrawn
• Conditions: Immune Thrombocytopenia
• Intervention / Treatment: Drug: Avatrombopag 20 mg Oral Tablet

Detailed Description

This phase 3b, multi-center, open-label study will enroll approximately 75 adult subjects with a confirmed diagnoses of primary ITP (≤6 months duration) who have had a previous response to a first line treatment. The study will consist of a 26-week treatment period to evaluate the safety and efficacy of avatrombopag. Subjects with platelet counts ≥50×10⁹/L at Week 26 may enter a dose-tapering period in which the dose of avatrombopag will be decreased for up to 16 weeks until avatrombopag treatment is discontinued and the platelet count is maintained ≥50×10⁹/L. Once avatrombopag treatment has been discontinued, the subjects will enter a remission evaluation period of up to 24 weeks to evaluate whether they have entered a state of remission.

• Study Type: Interventional
• Phase: Phase 3

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Male or female subjects ≥18 years of age at Screening.
2. Subject must be able to provide informed consent.
3. Subject has a confirmed diagnosis of primary ITP according to the International Consensus Report on the Investigation and Management of Primary ITP within the previous 6 months prior to Visit 1 and has had a previous response to a first line treatment (corticosteroids, IVIg, or anti-D), in the opinion of the Investigator.
4. Subject has at least one platelet count <30×10⁹/L at any time during the screening period or at the Baseline visit.
5. Females of childbearing potential must have a negative pregnancy test at Screening and Baseline.
6. Female subjects of childbearing potential who are sexually active and male subjects who are sexually active must agree to use effective methods of contraception.
7. Subject is willing and able to comply with all aspects of the protocol.

Exclusion Criteria:

1. Thrombocytopenia due to a known condition other than primary ITP (e.g., systemic lupus erythematosus, H. pylori infection, splenomegaly, chronic liver disease).
2. Any history of arterial or venous thrombosis, including partial or complete thrombosis (history of superficial thrombophlebitis is not exclusionary).
3. Subjects with known inherited thrombocytopenia (e.g., MYH-9 disorders).
4. History of myelodysplastic syndrome (MDS) or other hematologic malignancies.
5. Current history of significant cardiac arrhythmias or decompensated congestive heart failure.
6. History of hepatitis B (HBV), hepatitis C (HCV), or human immunodeficiency virus (HIV).
7. Previous use of eltrombopag, romiplostim, recombinant human TPO or other platelet-producing agents.
8. Surgical resection of the spleen.
9. Previous use of mycophenolate mofetil (MMF), rituximab (or other B-cell lymphocyte depleting agents), mercaptopurine (6-MP) or alkylating agents.
10. Concurrent malignant disease, other than non-melanoma skin cancer or cervical cancer in-situ.
11. Known allergy to avatrombopag or any of its excipients.
12. Subject is unable to take oral medication or has a malabsorption syndrome or any other uncontrolled gastrointestinal condition.
13. Enrollment in another clinical study with any investigational drug or device within 30 days of Day 1/Visit 2 (or 5 half-lives, whichever is longer); however, participation in observational studies is permitted.
14. Any clinically relevant abnormality which makes the subject unsuitable for participation in the study, in the opinion of the Investigator.
15. Considered unable or unwilling to comply with the study protocol requirements.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 20 mg Avatrombopag daily; Avatrombopag	Drug: Avatrombopag 20 mg Oral Tablet; Avatrombopag administered at a frequency to maintain a target platelet count between ≥50 and ≤150×10⁹/L; Other Names: Doptelet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative Number of Weeks of Platelet Response	Cumulative number of weeks of platelet response in which the platelet count is ≥50×10⁹/L during 6 months of treatment in the absence of rescue therapy.	6 Months of Active Treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Durable Platelet Response	Durable platelet response as defined by the incidence of subjects who have at least 6 out of 8 weekly platelet counts ≥50×10⁹/L during the last 8 weeks of treatment.	8 Weeks of Treatment
Incidence of ITP remission	Incidence of ITP remission as defined by platelet count ≥50×10⁹/L for 24 consecutive weeks with no ITP treatments (concomitant or rescue).	24 Consecutive Weeks
Incidence of subjects achieving a platelet count response	Incidence of subjects achieving a platelet count response (≥50×10⁹/L) during the active treatment period of the study.	6 Months of Active Treatment

Collaborators and Investigators

• Sponsor: Sobi, Inc.

Study record dates

Study Major Dates

• Study Start (Anticipated): October 14, 2021
• Primary Completion (Anticipated): April 6, 2024
• Study Completion (Anticipated): February 19, 2025

Study Registration Dates

• First Submitted: September 8, 2021
• First Submitted That Met QC Criteria: September 8, 2021
• First Posted (Actual): September 16, 2021

Study Record Updates

• Last Update Posted (Actual): October 22, 2021
• Last Update Submitted That Met QC Criteria: October 15, 2021
• Last Verified: October 1, 2021

More Information

Terms related to this study

• Keywords: ITP
• Additional Relevant MeSH Terms: Pathologic Processes; Immune System Diseases; Autoimmune Diseases; Hematologic Diseases; Hemorrhage; Hemorrhagic Disorders; Blood Coagulation Disorders; Skin Manifestations; Blood Platelet Disorders; Thrombotic Microangiopathies; Purpura, Thrombocytopenic; Purpura; Purpura, Thrombocytopenic, Idiopathic; Thrombocytopenia
• Other Study ID Numbers: AVA-ITP-306

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No