Moderna, Inc. (MRNA  ) CEO Stéphane Bancel appeared on CNBC's "Squawk Box" Thursday to discuss the company's promising new cancer vaccine developed in partnership with Merck & Company, Inc. .

What Happened: When combined with Keytruda, Moderna's new vaccine candidate mRNA-4157 (V940) reduced the risk of relapse or death by 49% in melanoma patients and showed a 62% lower risk of the cancer spreading, the Moderna CEO said.

"It's a big day for patients, and we are so excited," Bancel said. "We think it's a huge impact on melanoma, it's one in two people. Think about the number of lives that can be impacted, and people that can be saved and live a normal life despite a diagnosis of cancer."

Moderna's CEO told CNBC the treatment may reach some markets in Europe and Asia by 2025 and could enter the U.S. market by 2028.

Why It Matters: Moderna shares are down more than 50% year-to-date, and shares of rival drug-maker Pfizer, Inc. are down 49% this year. Some investors are concerned that many of the vaccine stocks that rose during the pandemic will continue to fall alongside declining demand for Covid vaccines.

When asked about the company's future growth, Bancel said, "Number one: we are gaining market share in Covid so that is good for sales growth. We are launching RSV in '24 so that's going to be great for sales growth because we have no sales of RSV in '23, and we have seven Phase 3 products in the pipeline."

MRNA Price Action: According to data from Benzinga Pro, Moderna shares are up by more than 9% at $85.76 at the time of publication.