Phase II Study of Arginine Deprivation Therapy With Pegargiminase in Patients With Relapsed Sensitive or Refractory Small-cell Lung Cancer

• Published in: Clinical lung cancer 2020-11, Vol.21 (6), p.527-533
• Main Authors: Hall, Peter E., Ready, Neal, Johnston, Amanda, Bomalaski, John S., Venhaus, Ralph R., Sheaff, Michael, Krug, Lee, Szlosarek, Peter W.
• Format: Article
• Language: English
• Subjects: ADI-PEG 20; Argininosuccinate synthetase 1; Auxotropy; Biomarker; SCLC
• ISSN: 1525-7304; 1938-0690
• DOI: 10.1016/j.cllc.2020.07.012

Pre-clinical studies indicated that arginine-deprivation therapy using pegylated arginine deiminase (pegargiminase, ADI-PEG 20) may be effective in patients with argininosuccinate synthetase 1 (ASS1)-deficient small-cell lung cancer (SCLC). Patients were enrolled into either a ‘sensitive’ disease cohort (≥ 90 days response to first-line chemotherapy) or a ‘refractory’ disease cohort (progression while on chemotherapy or < 90 days afterwards or ≥ third-line treatment). Patients received weekly intramuscular pegargiminase, 320 IU/m2 (36.8 mg/m2), until unacceptable toxicity or disease progression. The primary endpoint was tumor response assessed by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 with secondary endpoints including tolerability, pharmacodynamics, and immunogenicity. Between January 2011 and January 2014, 22 patients were enrolled: 9 in the sensitive disease cohort and 13 in the refractory disease cohort. At a pre-planned interim analysis, the best overall response observed was stable disease in 2 patients in each cohort (18.2%). Owing to the lack of response and slow accrual in the sensitive disease cohort, the study was terminated early. Pegargiminase treatment was well-tolerated with no unexpected adverse events or discontinuations. Although pegargiminase monotherapy in SCLC failed to meet its primary endpoint of RECIST-confirmed responses, more recent molecular stratification, including MYC status, may provide new opportunities moving forward. Recurrent small-cell lung cancer (SCLC) has limited chemotherapy options. Here, we report the outcome of the first trial of arginine-deprivation therapy (pegargiminase, ADI-PEG 20) in patients with relapsed/refractory SCLC. The best overall response to pegargiminase in SCLC was stable disease. Recent molecular stratification including MYC status and immune checkpoint blockade may leverage arginine-lowering therapy in SCLC going forward.