Phase 1/2 trial of talazoparib in combination with temozolomide in children and adolescents with refractory/recurrent solid tumors including Ewing sarcoma: A Children's Oncology Group Phase 1 Consortium study (ADVL1411)

Pediatr Blood Cancer. 2020 Feb;67(2):e28073. doi: 10.1002/pbc.28073. Epub 2019 Nov 14.


Purpose: We conducted a phase 1/2 trial of the poly(ADP-ribose) polymerase 1/2 inhibitor talazoparib in combination with low-dose temozolomide (TMZ) to determine the dose-limiting toxicities (DLTs), recommended phase 2 dose (RP2D), and pharmacokinetics of this combination in children with recurrent/refractory solid tumors; and to explore clinical activity in Ewing sarcoma (EWS) (NCT02116777).

Methods: Talazoparib (400-600 µg/m2 /dose, maximum daily dose 800-1000 µg) was administered q.d. or b.i.d. orally on day 1 followed by q.d. dosing concomitant with q.d. dosing of oral TMZ (20-55 mg/m2 /day) on days 2 to 6, every 28 days.

Results: Forty patients, aged 4 to 25 years, were enrolled. Talazoparib was increased to 600 µg/m2 /dose b.i.d. on day 1, and q.d. thereafter, with 20 mg/m2 /day of TMZ, without DLTs. TMZ was subsequently increased, during which dose-limiting neutropenia and thrombocytopenia occurred in two of three subjects at 55 mg/m2 /day, two of six subjects at 40 mg/m2 /day, and one of six subjects at 30 mg/m2 /day. During dose-finding, two of five EWS and four of 25 non-EWS subjects experienced prolonged stable disease (SD), and one subject with malignant glioma experienced a partial response. In phase 2, 0 of 10 EWS subjects experienced an objective response; two experienced prolonged SD.

Conclusions: Talazoparib and low-dose TMZ are tolerated in children with recurrent/refractory solid tumors. Reversible neutropenia and thrombocytopenia were dose limiting. The RP2D is talazoparib 600 µg/m2 b.i.d. on day 1 followed by 600 µg/m2 q.d. on days 2 to 6 (daily maximum 1000 µg) in combination with temozolomide 30 mg/m2 /day on days 2 to 6. Antitumor activity was not observed in EWS, and limited antitumor activity was observed in central nervous system tumors.

Keywords: PARP inhibitor; pharmacokinetics; phase 1; talazoparib; temozolomide.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Antineoplastic Combined Chemotherapy Protocols / pharmacokinetics
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Bone Neoplasms / drug therapy*
  • Bone Neoplasms / pathology
  • Child
  • Child, Preschool
  • Drug Resistance, Neoplasm / drug effects*
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Male
  • Maximum Tolerated Dose
  • Neoplasm Recurrence, Local / drug therapy*
  • Neoplasm Recurrence, Local / pathology
  • Phthalazines / administration & dosage
  • Prognosis
  • Salvage Therapy*
  • Sarcoma, Ewing / drug therapy*
  • Sarcoma, Ewing / pathology
  • Survival Rate
  • Temozolomide / administration & dosage
  • Tissue Distribution
  • Young Adult


  • Phthalazines
  • talazoparib
  • Temozolomide

Associated data