Radiation sensitization with sodium nitrite in patients with brain metastases: a pilot randomized controlled trial

Systemic administration of nitrite anion seems to be a practical way to produce local burst of nitric oxide, a hypoxic cell radiosensitizer in solid tumors. This randomized controlled pilot study assessed radiologic objective response rate (ORR) in patients suffered from brain metastases treated by whole-brain radiotherapy (WBRT) concurrent with intravenous infusion of sodium nitrite versus WBRT alone. Twenty patients were randomized into the following groups: Ten patients treated by WBRT (30 Gy in ten fractions over 2 weeks) concomitant with 2-hour intravenous infusion of sodium nitrite (267 µg/kg/h) before each fraction of radiation (WBRT + SN arm) and ten patients received the same schedule of WBRT, alone (control arm). ORR was measured according to response evaluation criteria in solid tumors (RECIST version 1.1). There were four radiologic objective responses in WBRT + SN arm compared with three in the control group without significant statistical difference (P = 1.00). In contrast, age ≤ 65 years (P = 0.05) and presence of extra-cranial metastases (P = 0.01) were predictor factors of ORR. In conclusion, intravenous infusion of sodium nitrite with this dose and schedule to patients with brain metastases concurrent with radiotherapy did not show any major benefit in terms of radiologic response.