Romiplostim for Chemotherapy-induced Thrombocytopenia Results from global phase iii trial in Gi cancers

From May 30 to June 3, 2025, the ASCO Annual Meeting will bring together thousands of oncologists, researchers, and industry leaders at Chicago’s McCormick Place. This premier global oncology event serves as a crucial platform for presenting groundbreaking research, exploring new cancer treatments, and defining the future of cancer care. Attendees can anticipate in-depth presentations on pivotal clinical trial results, lively discussions on innovative research, and vital insights focused on advancing patient care and equity in oncology.

What Is the Romiplostim Trial?

This was a global, phase 3, randomized, placebo-controlled trial (RCT) designed to evaluate the efficacy and safety of romiplostim for chemotherapy-induced thrombocytopenia (CIT) in patients receiving oxaliplatin-based multiagent regimens for gastrointestinal (GI) cancers, specifically colorectal, gastroesophageal, and pancreatic cancers. The study aimed to address the common clinical challenge of persistent CIT, ≤85×10⁹/L on day 1 of a scheduled chemotherapy cycle.

Trial Endpoints and Translational Aims

The primary endpoint of this trial was to determine if romiplostim could prevent CIT-induced dose modification of any myelosuppressive agent in either the second or third chemotherapy cycle, as adjudicated by an independent committee. This endpoint directly reflects a critical clinical goal: ensuring patients can receive their planned anticancer therapy without delays or dose reductions due to low platelet counts.

The translational aim of this study was to demonstrate that by stimulating platelet production, romiplostim could enable the timely and full-dose delivery of chemotherapy, thereby potentially improving treatment outcomes and patient quality of life by mitigating a common and serious chemotherapy complication. The study sought to establish romiplostim as a standard of care for CIT in this patient population, translating its known mechanism of action into tangible clinical benefit.

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Romiplostim Trial Results

The trial enrolled 165 patients across 55 sites in 14 countries, with 109 randomized to receive romiplostim and 56 to placebo. The patient population was primarily male (60%) and White (90%), with an average age of 61.4 years. Colorectal cancer was the most prevalent cancer type (75%), followed by gastroesophageal (13%) and pancreatic (12%) cancers. At baseline, the median platelet count was 69×10⁹/L. Patients received weekly subcutaneous romiplostim (starting at $2\mu \text{g}/\text{kg}$ and adjusted up to $10\mu \text{g}/\text{kg}$) or placebo for three chemotherapy cycles, with chemotherapy restarting once platelets reached ≥100×10⁹/L. Most patients (75%) completed the study drug.

Efficacy Outcomes

Romiplostim demonstrated significant efficacy in preventing CIT-induced chemotherapy dose modifications. The primary endpoint was achieved in 84% (92/109) of patients receiving romiplostim, compared to only 36% (20/56) of those on placebo (odds ratio 10.2; 95% CI 4.6-22.5; P<0.001).

Furthermore, romiplostim led to significantly higher platelet nadirs, with a median nadir of 87×10⁹/L for romiplostim versus 58×10⁹/L for placebo (P=0.005). The time to first platelet response was also notably faster with romiplostim, achieving a median of 1.1 weeks compared to 2.1 weeks for placebo (P<0.001), and a higher percentage of patients on romiplostim achieved a platelet response (97% vs 77% for placebo). These robust efficacy results underscore romiplostim’s ability to effectively manage and prevent CIT in this patient group.

Safety Profile

Romiplostim was generally well tolerated within the study. The rates of treatment-related adverse events (TRAEs) were low in both arms, with 12% in the romiplostim group and 7% in the placebo group. The most frequently reported TRAEs were mild, including nausea (2% in both arms) and headache (2% for romiplostim, 0% for placebo). Importantly, no treatment-related serious adverse events or TRAEs leading to death or discontinuation of either the study drug or chemotherapy were observed in either treatment arm. These findings suggest that romiplostim provides a beneficial efficacy profile for CIT without introducing significant safety concerns in patients undergoing chemotherapy for GI cancers. Final long-term follow-up results are anticipated to provide further safety insights.

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Written By Aren Karapetyan, MD