A phase I study of the antibody drug conjugate ASG-5ME, an SLC44A4-targeting antibody carrying auristatin E, in metastatic castration-resistant prostate cancer Journal Article


Authors: McHugh, D.; Eisenberger, M.; Heath, E. I.; Bruce, J.; Danila, D. C.; Rathkopf, D. E.; Feldman, J.; Slovin, S. F.; Anand, B.; Chu, R.; Lackey, J.; Reyno, L.; Antonarakis, E. S.; Morris, M. J.
Article Title: A phase I study of the antibody drug conjugate ASG-5ME, an SLC44A4-targeting antibody carrying auristatin E, in metastatic castration-resistant prostate cancer
Abstract: Background Antibody drug conjugates (ADC) offer the potential of maximizing efficacy while minimizing systemic toxicity. ASG-5ME, an SLC44A4-targeting antibody carrying monomethyl auristatin E (MMAE), a microtubule-disrupting agent, was investigated in men with metastatic castration resistant prostate cancer. Methods The primary objective of this phase I study was to determine maximum tolerated dose (MTD) and recommended phase II dose. Secondary objectives were safety, antitumor activity, pharmacokinetic properties, immunogenicity, and the detection of SLC44A4 on circulating tumor cells. Patients (pts) were treated among 7 dose levels every 21 days. A dose expansion phase enrolled 20 additional pts. at the MTD. Results Twenty-six and 20 pts. were treated in dose escalation and dose expansion cohorts respectively. The MTD was 2.7 mg/kg. Dose-limiting toxicities occurred in 4 pts.: grade 3 fatigue (n = 1); grade 3 abdominal pain, diarrhea and fatigue (n = 1); grade 4 neutropenia and hyponatremia and grade 3 maculopapular rash, constipation and hypoxia (n = 1); grade 3 troponin elevation without cardiac sequelae (n = 1). Fatigue and diarrhea were the most prevalent adverse events (AEs) across all cycles. Two grade 5 AEs occurred in the dose expansion cohort, each after 1 dose: 1 pt. developed grade 3 hyperglycemia, renal insufficiency and leukopenia; 1 pt. developed grade 3 hyperglycemia complicated by bacteremia. Free MMAE levels did not accumulate with repeat dosing. Of evaluable pts., 52% had either stable disease or a partial response. Conclusions Further development of ASG-5ME is not being pursued due to its narrow therapeutic index. Some toxicities were potentially related to on-target effects on normal tissue expressing the SLC44A4 protein. However, other toxicities were consistent with studies of previous MMAE-containing ADCs. Unconjugated MMAE is a less likely etiology based on prior data. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
Keywords: adult; clinical article; controlled study; aged; unclassified drug; constipation; fatigue; neutropenia; area under the curve; diarrhea; dose response; drug efficacy; drug safety; outcome assessment; antineoplastic agent; leukopenia; kidney failure; antineoplastic activity; abdominal pain; drug dose escalation; hyperglycemia; prostate cancer; hypoxia; hyponatremia; maculopapular rash; adverse outcome; multicenter study; immunogenicity; bacteremia; time to maximum plasma concentration; maximum tolerated dose; phase 1 clinical trial; drug half life; castration resistant prostate cancer; castration-resistant; human; male; priority journal; article; volume of distribution; maximum concentration; antibody drug conjugate; antibody drug conjugate asg 5me
Journal Title: Investigational New Drugs
Volume: 37
Issue: 5
ISSN: 0167-6997
Publisher: Springer  
Date Published: 2019-10-01
Start Page: 1052
End Page: 1060
Language: English
DOI: 10.1007/s10637-019-00731-5
PUBMED: 30725389
PROVIDER: scopus
PMCID: PMC6684870
DOI/URL:
Notes: Article -- Export Date: 1 November 2019 -- Source: Scopus
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MSK Authors
  1. Susan Slovin
    254 Slovin
  2. Michael Morris
    580 Morris
  3. Dana Elizabeth Rathkopf
    274 Rathkopf
  4. Daniel C Danila
    155 Danila
  5. Deaglan Joseph McHugh
    45 McHugh