Outcome of Patients With Malignant Peripheral Nerve Sheath Tumors Enrolled on Sarcoma Alliance for Research Through Collaboration (SARC) Phase II Trials

Background: Evaluation of prior phase II trials for malignant peripheral nerve sheath tumors (MPNST) may help develop more suitable trial endpoints in future studies. Methods: We analyzed outcomes of patients with recurrent or unresectable/metastatic MPNST enrolled on prior Sarcoma Alliance for Research through Collaboration (SARC) phase II trials and estimated the progression-free survival (PFS). PFS from SARC006 (NCT 00304083), the phase II trial of upfront chemotherapy in chemotherapy naive patients, was analyzed separately. Impact of baseline enrollment characteristics on PFS was evaluated. Results: Sixty-four patients (29 male, 35 female, median age 39 years (range 15-81)) with MPNST were enrolled on 1 of 5 trials of single agent or combination therapy that were determined to be inactive. Patients had received a median of 1 (range 0-5) prior systemic therapy, and most had undergone prior surgery (77%) and radiation (61%). Seventy-three percent had metastatic disease at enrollment. Median PFS was 1.77 months (95% CI, 1.61-3.45), and the PFS rate at 4 months was 15%. Greater number of prior systemic therapies and worse performance status were associated with inferior PFS. There was no significant difference in PFS based on age at enrollment, treatment trial, response criteria, presence of metastatic disease, disease site at enrollment, and prior surgery or radiation. In comparison, on the SARC006 trial the PFS rate at 4 months was 94% in 40 patients. Conclusion: These data provide a historical baseline PFS that may be used as a comparator in future clinical trials for patients with MPNST.