Xin Zhao

Abstract BRAF genomic alterations are the most common oncogenic drivers in pediatric low-grade glioma (pLGG). Arm 1 ( n = 77) of the ongoing phase 2 FIREFLY-1 (PNOC026) trial investigated the efficacy of the oral, selective, central nervous system–penetrant, type II RAF inhibitor tovorafenib (420 mg m − 2 once weekly; 600 mg maximum) in patients with BRAF -altered, relapsed/refractory pLGG. Arm 2 ( n = 60) is an extension cohort, which provided treatment access for patients with RAF -altered pLGG after arm 1 closure. Based on independent review, according to Response Assessment in Neuro-Oncology High-Grade Glioma (RANO-HGG) criteria, the overall response rate (ORR) of 67% met the arm 1 prespecified primary endpoint; median duration of response (DOR) was 16.6 months; and median time to response (TTR) was 3.0 months (secondary endpoints). Other select arm 1 secondary endpoints included ORR, DOR and TTR as assessed by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO) criteria and safety (assessed in all treated patients and the primary endpoint for arm 2, n = 137). The ORR according to RAPNO criteria (including minor responses) was 51%; median DOR was 13.8 months; and median TTR was 5.3 months. The most common treatment-related adverse events (TRAEs) were hair color changes (76%), elevated creatine phosphokinase (56%) and anemia (49%). Grade ≥3 TRAEs occurred in 42% of patients. Nine (7%) patients had TRAEs leading to discontinuation of tovorafenib. These data indicate that tovorafenib could be an effective therapy for BRAF -altered, relapsed/refractory pLGG. ClinicalTrials.gov registration: NCT04775485 .

Abstract BACKGROUND RAF alterations are oncogenic drivers found in most pediatric low-grade gliomas (LGGs). Tovorafenib is an investigational, oral, selective, CNS-penetrant, small molecule, type II pan‑RAF inhibitor. METHODS FIREFLY-1 (NCT04775485) is a multicenter phase 2 study evaluating the safety and efficacy of tovorafenib monotherapy. Registrational arm 1 enrolled patients with recurrent/progressive LGG harboring an activating BRAF alteration. Patients aged 6 months–25 years who progressed following ≥ 1 prior line of systemic therapy were eligible. Tovorafenib 420 mg/m2 (≤ 600 mg) was administered weekly (tablet or liquid suspension formulation) until progression or for ≥ 26, 28-day cycles. The primary endpoint (arm 1) was overall response rate, as defined by RANO criteria, per independent review. RESULTS As of April 14, 2022, 25 patients were enrolled to arm 1 and had ≥ 6 months of follow-up. Median age at enrollment was 8 years (range 3–18). Most patients had astrocytomas (92%), 48% with optic pathway involvement. Patients were heavily pretreated (56% with ≥ 3 prior lines of therapy), and 72% previously received MAPK pathway-targeted agents. Tumors harbored BRAF fusions (84%) or BRAF V600E mutations (16%). Per independent assessment, partial responses (1 unconfirmed) were seen in 14 (64%) of 22 evaluable patients, with 6 additional patients having stable disease, and a clinical benefit rate of 91%. Responses were achieved in tumors with BRAF fusions and V600E mutations. Most treatment-emergent adverse events (AEs) were grade 1 or 2 (96%). The most common grade ≥ 3 AEs were anemia (12%), vomiting, increased blood creatinine phosphokinase and maculopapular rash (8% each). Seven patients (28%) required dose modification for treatment-related AEs; no patients discontinued tovorafenib due to AEs. Updated results, including efficacy per RAPNO assessments will be presented. CONCLUSIONS Tovorafenib was generally well tolerated and showed encouraging evidence of antitumor activity in children with pretreated BRAF-altered LGG.

10004 Background: Pediatric low-grade gliomas (LGGs) are the most common brain tumors of childhood. Genomic alterations of BRAF ( KIAA1549-BRAF fusions, 50–60% and BRAF V600E mutations, 5–15%) are the most frequent oncogenic drivers in pLGGs. Tovorafenib is an investigational, oral, selective, brain-penetrant, small molecule, type II pan-RAF inhibitor. Tovorafenib has demonstrated clinically meaningful responses in 24/35 patients (2 CR, 7 PR and 15 SD) in the pediatric phase 1B PNOC014 (NCT03429803) trial in patients with RAF-altered cancers (Wright, SNO 2022). Methods: FIREFLY-1 (NCT04775485) is a multicenter phase 2 study evaluating the efficacy and safety of tovorafenib monotherapy in patients with BRAF-altered cancers. Registrational arm 1 of FIREFLY-1 includes patients 6 months–25 years of age with recurrent or progressive LGG previously treated with ≥1 prior line of systemic therapy. Tovorafenib 420 mg/m 2 (not to exceed 600 mg) is administered weekly, in 28-day cycles, (tablet or liquid suspension formulation) until progression. The primary endpoint of arm 1 is ORR, as defined by Response Assessment in Neuro-Oncology (RANO) criteria and determined by blinded independent review. Results: As of September 28, 2022, arm 1 had enrolled 77 patients and is fully accrued. All patients had ≥6 months of follow-up. Median age at enrollment was 8 years (range 2–21). Patients were pretreated with a median of 3 prior lines of systemic therapy (range: 1–9); 60% had received prior MAPK pathway-targeted agents. The most common tumor site was optic pathway (51%). Sixty-four patients harbored a BRAF fusion/rearrangement (83%) in their tumors, and 13 (17%) had a BRAF V600E mutation. Median duration of tovorafenib treatment is 8.4 months (range 0.7–16.8), with 59 patients (77%) remaining on treatment at the time of data cutoff. Per independent assessment in 69 RANO-evaluable patients, ORR was 64%, [3 CR, 41 PR (10 unconfirmed) and 19 SD] with a clinical benefit rate of 91%. Responses were achieved in tumors with BRAF fusions and V600E mutations, including those previously treated with MAPK inhibitors. The most common treatment-related adverse events (TRAEs) of any grade were hair color changes (75%), increased creatine phosphokinase (64%), anemia (46%), fatigue (42%) and maculopapular rash (42%). Tovorafenib dose modifications occurred in 16 (21%) and discontinuations in 2 (3%) patients due to TRAEs. Updates from a longer follow-up on the 77 patients in arm 1 will be presented at the meeting. Conclusions: Tovorafenib was generally well tolerated and showed encouraging evidence of antitumor activity in children and young adults with recurrent/progressive BRAF-altered pLGG. LOGGIC/FIREFLY-2 (NCT05566795), a global, phase 3 trial is evaluating once-weekly tovorafenib monotherapy in newly-diagnosed patients with pLGG harboring a known activating RAF alteration. Clinical trial information: NCT04775485 .

Abstract Methotrexate is a widely used drug in clinical practice for the treatment of collagen vascular diseases and malignant tumors. It has good anti-inflammatory and anti-proliferative effects, but the cytotoxicity of methotrexate can cause various adverse reactions in patients. Studies have shown that the sensitivity and tolerance of different individuals to methotrexate is different. There are many reasons for this difference. Among them, genetic polymorphism is one of the main factors that cause individual differences. This article provides an overview of the genetic polymorphisms of key proteins involved in methotrexate metabolism and transport, such as MTHFR, FPGS, γ-GGH, ABC transporter, OATPs, SLC, TS and DHFR, are related to their efficacy and adverse reactions. The aim is to clarify the impact of genetic polymorphisms on the efficacy and adverse effects of methotrexate at the pharmacogenomic level, in order to provide a basis for the clinical application of methotrexate.

Abstract BACKGROUND Genomic alterations and dysregulation of RAF are the main oncogenic driver in almost all pediatric low-grade gliomas (pLGGs). About 50%‒60% of pLGGs harbor KIAA1549-BRAF fusion and 5%‒15% BRAF V600E mutation. No targeted therapy has received regulatory approval for either relapsed or newly diagnosed pLGG to date. Tovorafenib is an investigational, oral, selective, CNS-penetrant, small molecule, type II panRAF inhibitor. The registrational, phase 2 FIREFLY-1 (NCT04775485) study with tovorafenib in pediatric patients with recurrent/progressive LGG is currently ongoing. METHODS LOGGIC/FIREFLY-2 (EudraCT 2022-001363-27) is a registrational, randomized, multicenter, global (~100 sites across Australia, Canada, Egypt, Europe, New Zealand, Singapore, South Korea, Taiwan, and USA), phase 3 trial evaluating the efficacy, safety, and tolerability of tovorafenib vs. standard of care (SoC) chemotherapy in patients < 25 years old with LGG harboring a RAF-alteration and requiring first-line systemic therapy. Approximately 400 patients will be randomized 1:1 to receive oral tovorafenib, 420 mg/m2 ( ≤ 600 mg) weekly (tablet or liquid suspension for 26, 28-day cycles), or an investigator’s choice of SoC chemotherapy: COG-V/C regimen (60 weeks), SIOPe-LGG-V/C (81 weeks) regimen, or single-agent vinblastine (70 weeks). After completing 26 cycles tovorafenib, patients may continue tovorafenib or opt to enter a drug holiday at any point. Patients who progress in the SoC arm may receive tovorafenib. Patients who progress after stopping tovorafenib may be re-challenged. Primary endpoint is ORR based on RANO criteria, as determined by an independent radiology committee. Key secondary endpoints are progression-free survival and duration of response per RANO criteria, and ORR per RAPNO criteria. Other secondary endpoints include changes in neurological and visual function, and safety and tolerability. Exploratory objectives include quality of life and health utilization measures, molecular biomarker evaluation for treatment response and resistance, efficacy of tovorafenib after progression on chemotherapy and retreatment upon progression during drug holiday.