Drugmaker Moderna\u0027s stock more than doubled on Wednesday morning after the company announced a successful experimental mRNA vaccine to treat melanoma, the deadly skin cancer from which more than 8,500 people\u00a0in the U.S. are expected to die this year.Moderna and Merck, its drug development partner,\u00a0said the novel treatment prevented melanoma from returning or spreading in a study of high-risk melanoma patients.Shares of Moderna surged $91.52, or 145%, to $154.48 in morning trading after touching an intraday high of $163. Merck\u0027s shares rose $14.35, or 10.6%, to $149.52.\u00a0The study, which focused on people who had undergone surgery to remove a melanoma, tested the drug\u0027s efficacy at reducing the risk of the cancer\u0027s return.\u00a0The study tested the companies\u0027 personalized cancer vaccine intismeran in combination with Merck\u0027s Keytruda, its cancer immunotherapy drug. Together, the drugs kept the cancer from returning for longer and prevented it from spreading to other organs.\u00a0The drugmakers plan to present the unpublished data to regulators at an upcoming international medical meeting."Landmark moment"\u00a0"Today\u0027s results represent a landmark moment for adjuvant melanoma treatment," Professor Georgina Long, the study\u0027s principal investigator and the chair of University of Sydney\u0027s Melanoma Medical Oncology and Translational Research, said in a statement Wednesday.\u00a0Long said the study is the first of its kind to show that treatment can "reduce the risk of recurrence or death in patients" with melanoma.\u00a0The advancement "has the potential to establish a new treatment paradigm in the adjuvant melanoma setting, helping patients remain cancer-free for longer," she added.\u00a0More than 234,680 cases of melanoma will be diagnosed in the U.S. in 2026, according to the Skin Cancer Foundation. Among the deadliest forms of skin cancer, melanoma starts in melanocytes, the cells that give the skin its color. Melanoma is characterized by the uncontrollable growth of these cells, according to the Mayo Clinic.\u00a0"By intervening earlier in the course of disease, when many cancers are considered most treatable, the goal of adjuvant therapy given after surgery is to increase the possibility of cure for more patients," Dr. Dean Y. Li, president of Merck Research Laboratories, said in a statement.\u00a0The findings amount to a "pivotal moment for the field of cancer research," added Moderna CEO St\u00c3\u00a9phane Bancel. "For many years, the idea of creating an mRNA treatment designed specifically for an individual patient\u0027s cancer was aspirational. We are now helping turn that vision into a reality."Moderna shares are still far from their pandemic-era peak in late 2021 and 2022, when its stock soared on global demand for its COVID-19 vaccine.\u00a0