Human interleukin-12 (hIL-12) is a cytokine with anticancer activity, but its systemic application is limited by toxic inflammatory responses. We assessed the safety and biological effects of an hIL-12 gene, transcriptionally regulated by an oral activator. A multicenter phase 1 dose-escalation trial (NCT02026271) treated 31 patients undergoing resection of recurrent high-grade glioma. Resection cavity walls were injected (day 0) with a fixed dose of the hIL-12 vector (Ad–RTS–hIL-12). The oral activator for hIL-12, veledimex (VDX), was administered preoperatively (assaying blood-brain barrier penetration) and postoperatively (measuring hIL-12 transcriptional regulation). Cohorts received 10 to 40 mg of VDX before and after Ad–RTS–hIL-12. Dose-related increases in VDX, IL-12, and interferon-γ (IFN-γ) were observed in peripheral blood, with about 40% VDX tumor penetration. Frequency and severity of adverse events, including cytokine release syndrome, correlated with VDX dose, reversing promptly upon discontinuation. VDX (20 mg) had superior drug compliance and 12.7 months median overall survival (mOS) at mean follow-up of 13.1 months. Concurrent corticosteroids negatively affected survival: In patients cumulatively receiving >20 mg versus ≤20 mg of dexamethasone (days 0 to 14), mOS was 6.4 and 16.7 months, respectively, in all patients and 6.4 and 17.8 months, respectively, in the 20-mg VDX cohort. Re-resection in five of five patients with suspected recurrence after Ad–RTS–hIL-12 revealed mostly pseudoprogression with increased tumor-infiltrating lymphocytes producing IFN-γ and programmed cell death protein 1 (PD-1). These inflammatory infiltrates support an immunological antitumor effect of hIL-12. This phase 1 trial showed acceptable tolerability of regulated hIL-12 with encouraging preliminary results.

Many mammalian cells release extracellular vesicles (EV) into circulation. These vesicles differ in ontogeny, size, and molecular composition. 1-5 The two most abundant fractions of EV are termed microvesicles (MV; 200-1000 nm), formed by budding of the cell membrane, and exosomes (EX; 50-200 nm), derived from multivesicular bodies. The last few years have seen intense interest in these vesicles given their biological role in cancer 6-9 and potential for diagnostic and therapeutic purposes. 10-13 To date, vesicles are often differentiated by size and density criteria 14-16 and the presence