Phase I trial of lorlatinib in combination with topotecan/cyclophosphamide in children with ALK-driven refractory or relapsed neuroblastoma: A new approaches to neuroblastoma therapy consortium study.
Authors: Goldsmith Kelly C. , Mosse Yael P. , Kayser Kimberly , Chi Yueh-Yun , Chioda Marc , Thurm Holger C. , Chen Joseph , Krishnaswami Sriram , Peltz Gerson , Granger Meaghan , Mody Rajen , Marshall Lynley V. , Desai Ami Vijay , Berko Esther , Maris John M. , Matthay Katherine K. , Ghazarian Suzy , Park Julie R. , Marachelian Araz 
Published: June 2022

10041 Background: Lorlatinib, a macrocyclic ATP-competitive ALK inhibitor, exerts potent activity against neuroblastoma (NB) xenograftsharboring the most common ALK mutations. We performed a first-in-child phase 1 study of lorlatinib for patients with refractory/relapsed (R/R) ALK aberrant high-risk NB. We previously reported on Part A of the study, where safety of single agent lorlatinib was determined, showing complete responses (CR) to lorlatinib at the recommended phase 2 dose (RP2D) of 115 mg/m2 in pts < 18 years and 150 mg in pts > 18 yrs. Part B of the study aimed to determine the safety, pharmacokinetics (PK), RP2D, and explore the anti-tumor activity of lorlatinib in combination with topotecan and cyclophosphamide in pts with R/R ALK-driven NB. Methods: Patients with R/R NB ages 1-17 years with ALK mutations or amplification were eligible; prior ALK inhibitor (ALKi) treatment was allowed. Lorlatinib was orally administered once daily on days 1-28 with topotecan (0.75 mg/m2/day) and cyclophosphamide (250 mg/m2/day) administered intravenously days 1-5 and GCSF starting day 6. Two lorlatinib dose levels (DL) of 95 mg/m2/day (DL4B) and 115 mg/m2/day (DL5B) were assessed using a 3+3 dose escalation design with the primary endpoint of dose limiting toxicity (DLT) in Course 1. We report lorlatinib safety, PK, and objective response rate (ORR) for patients enrolled on Part B. Results: Between 10FEB2020 and 03DEC2021,9 eligible pts enrolled on Part B with a median age of 6.7 years (3.7-12.7). Three pts were enrolled onto DL4B and six onto DL5B (2/3 pts on DL4B and 4/6 pts on DL5B had received prior ALKi therapy) with no DLT’s observed in course 1. One patient on DL5B experienced a neuropsychological DLT in Course 3. Most common treatment-related adverse events were hematological, febrile neutropenia, high cholesterol, hypertriglyceridemia, and neuropsychological effects. The median number of courses received was 6 with a range of 1-8 on DL4B and 1-7 on DL5B. Of the 8 patients evaluable for response, ORR was 50%: 2/3 pts on DL4B and 2/5 pts on DL5B. Preliminary PK data demonstrate comparable dose level-associated lorlatinib steady state exposure between Part B chemotherapy combination and Part A monotherapy cohorts, supporting that chemotherapy had no effect on lorlatinib exposure that there are no overlapping toxicities. Conclusions: Lorlatinib in combination with topotecan and cyclophosphamide is well tolerated, and early data suggest encouraging objective anti-tumor activity. These data support the current integration of lorlatinib into up-front high risk neuroblastoma therapy for patients with ALK-driven neuroblastoma. Clinical trial information: NCT03107988.