A Phase II Trial of Guadecitabine in Children and Adults with SDH-Deficient GIST, Pheochromocytoma, Paraganglioma, and HLRCC-Associated Renal Cell Carcinoma

Clin Cancer Res. 2023 Jan 17;29(2):341-348. doi: 10.1158/1078-0432.CCR-22-2168.


Purpose: Succinate dehydrogenase (dSDH)-deficient tumors, including pheochromocytoma/paraganglioma, hereditary leiomyomatosis and renal cell cancer-associated renal cell carcinoma (HLRCC-RCC), and gastrointestinal stromal tumors (GIST) without KIT or platelet-derived growth factor receptor alpha mutations are often resistant to cytotoxic chemotherapy, radiotherapy, and many targeted therapies. We evaluated guadecitabine, a dinucleotide containing the DNA methyltransferase inhibitor decitabine, in these patient populations.

Patients and methods: Phase II study of guadecitabine (subcutaneously, 45 mg/m2/day for 5 consecutive days, planned 28-day cycle) to assess clinical activity (according to RECISTv.1.1) across three strata of patients with dSDH GIST, pheochromocytoma/paraganglioma, or HLRCC-RCC. A Simon optimal two-stage design (target response rate 30% rule out 5%) was used. Biologic correlates (methylation and metabolites) from peripheral blood mononuclear cells (PBMC), serum, and urine were analyzed.

Results: Nine patients (7 with dSDH GIST, 1 each with paraganglioma and HLRCC-RCC, 6 females and 3 males, age range 18-57 years) were enrolled. Two patients developed treatment-limiting neutropenia. No partial or complete responses were observed (range 1-17 cycles of therapy). Biologic activity assessed as global demethylation in PBMCs was observed. No clear changes in metabolite concentrations were observed.

Conclusions: Guadecitabine was tolerated in patients with dSDH tumors with manageable toxicity. Although 4 of 9 patients had prolonged stable disease, there were no objective responses. Thus, guadecitabine did not meet the target of 30% response rate across dSDH tumors at this dose, although signs of biologic activity were noted.

Trial registration: ClinicalTrials.gov NCT03165721.

Publication types

  • Clinical Trial, Phase II
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adrenal Gland Neoplasms*
  • Adult
  • Biological Products*
  • Carcinoma, Renal Cell* / drug therapy
  • Carcinoma, Renal Cell* / genetics
  • Child
  • Female
  • Gastrointestinal Stromal Tumors* / genetics
  • Humans
  • Kidney Neoplasms*
  • Leukocytes, Mononuclear / metabolism
  • Male
  • Middle Aged
  • Paraganglioma* / drug therapy
  • Paraganglioma* / genetics
  • Pheochromocytoma*
  • Succinate Dehydrogenase / genetics
  • Young Adult


  • Succinate Dehydrogenase
  • guadecitabine
  • Biological Products

Supplementary concepts

  • Hereditary leiomyomatosis and renal cell cancer

Associated data

  • ClinicalTrials.gov/NCT03165721