rhTPO Dose Escalation vs Eltrombopag Switch in ITP

Platelet Response Rate (RR) at 6 weeks after switching treatment: proportion of patients with PLT ≥ 30×10⁹/L, at least 2-fold increase from baseline platelet count, and no bleeding manifestations

This primary endpoint was defined as the proportion of patients who met the "platelet response" criteria at the 6th week (±1 days) after switching from baseline treatment to the intervention plan of this study. "Platelet response" requires the simultaneous satisfaction of the following three conditions: 1) Platelet count ≥ 30 × 10⁹/L; 2) The platelet count has increased by at least twice compared to the baseline value; 3) There were no bleeding events requiring medical intervention or having clinical significance (WHO bleeding grade 0-1). The calculation formula is: (Number of patients achieving response/total number of patients conforming to the protocol analysis set) × 100%.

Proportion of patients with at least one PLT ≥ 50×10⁹/L at week 6

This indicator assesses the proportion of patients who reach the clinically significant platelet count threshold early after switching to the study intervention protocol. The specific definition is: the percentage of patients with a measured platelet count of ≥ 50 × 10⁹/L in the visit at the 6th week (day 42, with the visiting window being days 41 to 43) after treatment conversion, among the total number of patients in the protocol analysis set. This threshold (50×10⁹/L) is generally regarded as significantly reducing the risk of spontaneous bleeding and is one of the important criteria for evaluating treatment response. Calculation formula: (Number of patients with platelet count ≥ 50×10⁹/L at the 6th week visit/total number of patients conforming to the protocol analysis set) × 100%.

Time to Response (TTR)

The time from the initiation of treatment switching to the first PLT count ≥30×10⁹/L (in days) was recorded. For patients who did not achieve CR or R by the end of the study, the last efficacy assessment date was used as the censored date.

Sustained Response Rate (SRR)

Proportion of patients who, after achieving initial response and without other ITP therapeutic interventions or rescue treatments, maintain PLT \> 30×10⁹/L at week 6 or 12 without bleeding symptoms.

Response Rate (RR), proportion with PLT ≥ 50×10⁹/L, and Complete Response rate (CR, i.e., PLT ≥ 100×10⁹/L without bleeding manifestations) at each visit.

This indicator aims to dynamically evaluate hematological responses of different grades during the treatment period and the follow-up period. The specific definition is as follows: 1) Total response rate: It is defined as the proportion of patients with a platelet count of ≥30×10⁹/L, at least doubling from the baseline, and no bleeding manifestations. 2) Proportion of patients with platelet count ≥50×10⁹/L: Defined as the percentage of such patients. 3) Complete remission rate: Defined as the proportion of patients with a platelet count of ≥100×10⁹/L and no bleeding manifestations. The above three proportions will be calculated separately at each scheduled visit point. The denominators of each proportion are the total number of patients in the protocol analysis set who have valid platelet count and bleeding assessment data at the corresponding visit points.

The incidence of serious adverse events (SAE) during treatment

Any adverse events during treatment (including but not limited to thrombosis, hepatic function abnormalities, rash, etc.). The proportion of patients who experienced any serious adverse events from the start of the first administration to 30 days after the last administration. The definition of serious adverse events follows the ICH-GCP guidelines. The calculation formula is: (the number of patients with SAE/the total number of patients in the safety analysis set) × 100%.

Bleeding events

This indicator assesses the occurrence and severity of bleeding events during the treatment period and follow-up period. It includes the following two parts: 1) Incidence of bleeding: Defined as the proportion of patients who experienced any grade (including mild and severe) of bleeding events from the start of the first administration to the end of the last follow-up. The calculation formula is: (the number of patients with ≥1 bleeding event/the total number of patients in the safety analysis set) × 100%. 2) Bleeding score: Each bleeding event is graded using the World Health Organization's bleeding grading standard and ITP-BAT bleeding score. The highest bleeding grade for each patient during the treatment period and the cumulative incidence of bleeding events of each grade will be reported.

Platelet transfusion rate

Proportion of patients requiring at least one platelet transfusion during the study period. Transfusion records will be based on medical records and will document the cause and dosage of each transfusion.

Mean number of platelet transfusions per patient

Average number of platelet transfusions per patient during the study period, calculated as total number of transfusions divided by total number of study population. Transfusion records will be based on medical records and will document the cause and dosage of each transfusion.