American Association for Cancer Research
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Table S3 from First-in-Human Phase I Study of the Activin A Inhibitor, STM 434, in Patients with Granulosa Cell Ovarian Cancer and Other Advanced Solid Tumors

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journal contribution
posted on 2023-03-31, 21:01 authored by Jessica J. Tao, Nicholas A. Cangemi, Vicky Makker, Karen A. Cadoo, Joyce F. Liu, Drew W. Rasco, Willis H. Navarro, Christopher M. Haqq, David M. Hyman

Baseline, end of treatment, and change in ECOG performance status from baseline to end of treatment is reported below. Abbreviations: ECOG, Eastern Cooperative Oncology Group.


Atara Biotherapeutics



STM 434 is a soluble receptor ligand trap targeting activin A, a protein in the TGFβ family that plays important roles in growth, differentiation, and cancer cachexia. This study evaluated the safety, antitumor activity, and metabolic effects of STM 434 in a first-in-human, multicenter, phase I clinical trial (NCT02262455). Patients with advanced solid tumors were enrolled in 8 dose cohorts ranging from 0.25 mg/kg every 4 weeks to 8 mg/kg every 2 weeks via a 3 + 3 dose-escalation design. The primary endpoint was maximum tolerated dose (MTD). Secondary endpoints included safety, pharmacokinetics, and response. As activin A is implicated in metabolism and muscle function, changes in key metabolic parameters, including lean body mass and 6-minute walk test, were serially measured. Thirty-two patients were treated on study. The most common treatment-related adverse events were fatigue (41%) and mucocutaneous bleeding complications including epistaxis (34%) and gingival bleeding (22%), likely related to off-target inhibition of bone morphogenetic protein 9 (BMP9). STM 434 treatment resulted in the expected follicle-stimulating hormone level decreases in most patients and in metabolic parameter changes, including an increase in total lean body mass and 6-minute walk test distance. No responses were observed in the 30 evaluable patients, but the stable disease rate in patients with granulosa cell ovarian cancer was 10 of 12 (80%). Although no direct antitumor efficacy was documented, potentially clinically meaningful dose-related metabolic effects, including treatment of cancer cachexia, were observed that support further exploration of activin A inhibitors that limit BMP9 blockade.See related commentary by Bonilla and Oza, p. 5432