An open-label multi-center phase 1 safety study of BXQ-350 in children and young adults with relapsed solid tumors, including recurrent malignant brain tumors.

Background: BXQ-350 is a novel anti-neoplastic agent composed of saposin C (SapC) and phospholipid dioleoylphosphatidyl-serine sodium (DOPS) that selectively binds tumor cell phosphatidylserine (PS), inducing apoptosis. BXQ-350 has demonstrated preclinical antitumor effects in high-grade gliomas (HGG) and clinical activity in adult patients with recurrent HGG. Methods: A phase 1 study was conducted in pediatric patients with relapsed/refractory solid tumors, including recurrent brain tumors. Primary objectives were to characterize safety and determine maximum tolerated dose (MTD) and preliminary antitumor activity. Sequential dose cohorts were assessed up to 3.2 mg/kg using an accelerated titration design. Each cycle was 28 days; dosing occurred on days 1-5, 8, 10, 12, 15, and 22 of cycle 1, and day 1 of subsequent cycles, until disease progression or toxicity. Results: Nine patients, median age 10 years (range: 4-23), were enrolled. Seven patients (78%) had central nervous system (CNS) and two (22%) had non-CNS tumors. Eight patients completed cycle 1. No dose limiting toxicity (DLT) or BXQ-350-related serious adverse events (SAEs) were observed. Six patients experienced at least one adverse event (AE) considered possibly BXQ-350-related, most were grade ≤2. One patient with diffuse intrinsic pontine glioma experienced stable disease for 5 cycles. The study was terminated after part 1 to focus development on the frontline setting. Conclusion: No DLTs or BXQ-350-related SAEs were reported, and the maximal planned dose of 3.2 mg/kg IV was tolerable. Limited safety and efficacy data support continued BXQ-350 development in pediatric HGG; however, early discontinuations for progression suggest novel therapies be assessed at earlier disease stages.

Bevacizumab in high-grade gliomas: past, present, and future.

The survival of patients with high-grade gliomas (anaplastic gliomas and glioblastoma) remains poor despite current treatment modalities. However, an enhanced understanding of gliomagenesis is supporting the development of targeted molecular therapies with the potential for improving clinical outcomes. Glioblastoma (GBM) is characterized by extensive microvascular proliferation and the production of large amounts of VEGF. Bevacizumab is a humanized IgG1 monoclonal antibody that selectively binds with high affinity to human VEGF and neutralizes VEGF's biologic activity. Preclinical data indicate that angiogenesis is essential for the proliferation and survival of GBM cells. A number of studies have evaluated the outcomes of both newly diagnosed and recurrent GBM patients with bevacizumab in a prospective manner. Here, we discuss the role of bevacizumab in the treatment of anaplastic gliomas and GBM in the recurrent and upfront setting.