Herpes has never been known for its good PR. But the virus that causes cold sores might finally have something to brag about.At the University of Southern California, researchers have genetically modified herpes simplex virus type 1 (HSV-1) into a cancer-fighting weapon. When paired with an anti-cancer drug, the unlikely combo shrank tumors in a third of patients with advanced melanoma, skin cancer that had already spread and stopped responding to treatment. Even more shocking, nearly one in six saw their tumors completely disappear.“These findings are very encouraging,” Dr. Gino Kim In, a medical oncologist with Keck Medicine of USC, told the New York Post. “About half of all advanced melanoma cases cannot be managed with currently available immunotherapy treatments.”Doctors Have Figured Out a Way To Use Herpes To Fight CancerOnce melanoma moves beyond the skin and into places like the liver or brain, treatment options get slim fast. But this therapy, called RP1, works by injecting a virus directly into tumors, where it infects and destroys cancer cells while sparing the healthy stuff. It’s paired with nivolumab, a drug that helps unmask tumors so the immune system can go after them.“The survival rate of untreatable advanced melanoma is only a few years,” said In. “This new therapy offers hope to patients who may have run out of options.”Patients in the study received the injections every two weeks for a few months. If it started working, they continued taking just nivolumab once a month for up to two years. But the wildest part? Even tumors that weren’t injected started shrinking.That means the virus might be kicking the immune system into high gear across the entire body, not just in the treated areas.“This result suggests that RP1 is effective in targeting cancer throughout the entire body and not just the injected tumor,” said In.The treatment was also well-tolerated, with no major complications. Full results were published in the Journal of Clinical Oncology and presented at the American Society of Clinical Oncology’s annual meeting.A larger Phase 3 trial is already underway, involving more than 400 participants, and researchers are still looking for volunteers. Anyone interested in joining can contact Sandy Tran at sandy.tran@med.usc.edu.The post Doctors Are Using Herpes To Kill Cancer—and It’s Actually Working appeared first on VICE.