After nearly a decade of labor, PIN Pharma Inc. reported success in its first-in-human, open-label, repeat-dose trial of immunomodulating precision immune stimulant (PIN)-2 in participants with advanced solid tumors. The New York-based company said rapid onset of action was signaled by a surge in circulating tumor necrosis factor (TNF)-alpha six hours after injection of PIN-2, a derivative of the HIV-1 Tat protein that activates monocyte-derived dendritic cells. Circulating TNF-alpha levels subsequently returned to baseline. A similar but more pronounced finding was observed during a second cycle of treatment, confirming proof of mechanism for the immunomodulatory effect of PIN-2 and corroborating results seen in human monocytes in vitro.