A phase 2 PBTC study of selumetinib for recurrent/progressive pediatric low-grade glioma: Strata 2, 5, and 6 with long-term outcomes on strata 1, 3, and 4
Jason Fangusaro, Arzu Onar‐Thomas, Tina Young Poussaint, Shelly Lensing, Azra H. Ligon, Neal Lindeman, Anuradha Banerjee, Lindsay Kilburn, Alicia Lenzen, Natasha Pillay‐Smiley, Ian F. Pollack, Nathan Robison, Sonia Partap, Ibrahim Qaddoumi, Daniel Landi, David Jones, Clinton F. Stewart, Maryam Fouladi, Ira J. Dunkel
Abstract
BACKGROUND: PBTC-029B was a phase 2 trial evaluating efficacy of selumetinib in children with recurrent/progressive low-grade glioma. We report results of strata 2, 5, and 6 with updated survivals for strata 1, 3, and 4. METHODS: Stratum 2 included recurrent/progressive pilocytic astrocytoma (PA) not associated with neurofibromatosis type-1 (NF1) that screened negative for the BRAF-KIAA1549 fusion and BRAFV600E mutation. Stratum 5 enrolled non-PA that screened positive for one of the BRAF aberrations. Stratum 6 enrolled children who consented to tissue screening, but there was an assay failure. For long-term survivals, stratum 1 included non-NF1 PA positive for one of the BRAF aberrations; stratum 3 included NF1-associated pLGG; and stratum 4 included non-NF1 optic pathway/hypothalamic tumors. RESULTS: Stratum 2: among 14 evaluable patients, there was 1 partial response (PR), 7 stable disease (SD), and 6 progressive disease (PD); the overall response rate (ORR) was 7.1%. Two-year progression-free survival (PFS)/overall survival (OS) were 57.1%/100%, respectively. Stratum 5: among 23 evaluable patients, there was 1 complete response (CR), 4 PR, 12 SD, and 6 PD; ORR was 21.7%. Two-year PFS/OS were 74.8%/100%, respectively. Stratum 6: among 26 evaluable patients, there were 7 PR, 14 SD, and 5 PD; ORR was 26.9%. Two-year PFS/OS were 72.0%/100%, respectively. The median follow-up for patients on strata 1, 3, and 4 without events are 60.4, 60.4, and 58.1 months, and 5-year PFS/OS were 30.8%/88.9%, 54.2%/100%, and 51.0%/100%, respectively. CONCLUSIONS: Selumetinib provided stability and responses across many pLGG subgroups, and some patients achieved prolonged disease control without additional therapy.