Blood-Brain Barrier Permeabilization with Engineered Tumor Necrosis Factor-α Followed by R-CHOP Is an Active and Safe Salvage Therapy in Primary CNS Lymphoma

Background: R-CHOP is the standard treatment of diffuse large B-cell lymphoma (DLBCL). Primary DLBCL of the CNS (PCNSL) is an exception because of the low CNS bioavailability of related drugs. TNF-α fused to the NGR peptide targets CD13+ vessels and enhances vascular permeability and CNS access of anticancer drugs. Thus, we tested the hypothesis that NGR-hTNF conjugate can break the blood-brain barrier, thereby improving CNS access and activity of R-CHOP in patients with relapsed/refractory PCNSL. Methods : In this phase II trial, we addressed activity and safety of R-CHOP preceded by low-dose NGR-hTNF in patients with PCNSL relapsed or refractory to methotrexate-based chemotherapy. Overall response rate (ORR) was the primary endpoint. Sample size estimated to demonstrate an improvement from 30% ORR to 50% was 28 patients. NGR-hTNF/R-CHOP would be declared active if ≥12 responses were recorded. Secondary endpoints included safety, predictive value of NGR-hTNF inhibitors (chromogranin A; soluble TNF receptors), and expression of CD13 by tumor vessels. Findings: 28 patients (median age 58 years, range 26-78; 14 males) were enrolled. Patients were heavily pretreated: 25 had received autologous transplantation, whole-brain irradiation or both. NGR-hTNF/R-CHOP was active, with confirmed tumor response in 21 patients (75%;95%CI=59-91%), which was complete in 11. At a median follow-up of 18 (12-29) months, five patients remain relapse-free and six are alive. Treatment was well tolerated; there were no cases of unexpected toxicities, dose reductions or interruptions. High plasma levels of chromogranin A were associated with proton pump inhibitors use and lower remission rate. CD13 was expressed by both pericytes and endothelial cells of PCNSL samples. Interpretation: NGR-hTNF/R-CHOP is active and safe in patients with relapsed/refractory PCNSL. Its activity is in line with the expression of CD13, the target of TNF, in tumor vessels. Proton pump inhibitors should be avoided during TNF-based therapy. This innovative approach deserves to be addressed as first-line treatment in PCNSL patients. Trial Registration: EudraCT number 2014-001532-11. Funding Statement: The INGRID trial was performed without commercial funding. It was supported by a grant from the Leukemia and Lymphoma Society (A.J.M.F.; Grant ID Number: 6510-17) and, in part, by a grant from the Associazione Italiana Ricerca control il Cancro (A.C.; Grant ID Number: IG-23470). NGR-hTNF was kindly provided by Molmed SpA (Milano, Italy). Declaration of Interests: No potential conflicts of interest are disclosed by the authors, with the exception of C.B. who reports employment and equity ownership from MolMed SpA, and A.C. who reports consultancy to MolMed SpA, during the conduct of the study. A.C and F.C. are inventors of a patent on NGR-hTNF. Ethics Approval Statement: Written informed consent was obtained from each patient. This trial conformed to the Declaration of Helsinki and was approved by the IRB of the San Raffaele Scientific Institute of Milano, Italy.