Tumor volumes as a predictor of response to the anti-EGFR antibody drug conjugate depatuxizumab mafadotin

Hui K. Gan, Sagun Parakh, Andrew B. Lassman, Aidan Seow, Eddie Lau, Sze Ting Lee, Malaka Ameratunga, Yuliya Perchyonok, Diana Cao, Ingrid J.G. Burvenich, Graeme J. O'keefe, Angela Rigopoulos, Erica Gomez, David Maag, Andrew M. Scott

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10 Citations (Scopus)

Abstract

Background: The adverse impact of increasing brain tumor size on the efficacy of antibody-drug conjugates (ADCs) was investigated preclinically then validated with clinical data. Methods-Preclinical study: The impact of tumor size on ADC tumor delivery and treatment response was evaluated in an EGFR-amplified patient-derived glioblastoma (GBM) model following treatment with Depatuxizumab mafadotin (Depatux-M). Biodistribution and imaging studies correlated drug distribution with starting treatment volume and anti-tumor activity. Methods-Clinical study: M12-356 was a Phase I study of Depatux-M in patients with GBM. Blinded volumetric analysis of baseline tumor volumes of M12-356 patients was undertaken by two reviewers and results correlated with response and survival. Results: Preclinically, imaging and biodistribution studies showed specific and significantly higher tumor uptake of zirconium-89 labeled Depatux-M (89Zr-Depatux-M) in mice with smaller tumor volume (~98 mm3) versus those with larger volumes (~365 mm3); concordantly, mice with tumor volumes ≤100 mm3 at treatment commencement had significantly better growth inhibition by Depatux-M (93% vs 27%, P <. 001) and significantly longer overall survival (P <. 0001) compared to tumors ≥400 mm3. Clinically, patients with tumor volumes <25 cm3 had significantly higher response rates (17% vs. 0%, P =. 009) and longer overall survival (0.5 vs 0.89 years, P =. 001) than tumors above 25 cm3. Conclusion: Both preclinical and clinical data showed intra-tumoral concentration and efficacy of Depatux-m inversely correlated with tumor size. This finding merit further investigation with pretreatment tumor volume as a predictor for response to ADCs, in both gliomas and other solid tumors.

Original languageEnglish
Article numbervdab102
Number of pages9
JournalNeuro-Oncology Advances
Volume3
Issue number1
DOIs
Publication statusPublished - Jan 2021
Externally publishedYes

Keywords

  • depatuxizumab mafadotin
  • GBM
  • tumor volume

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