Merck’s Pneumococcal Shot Claims Back-to-Back Phase III Wins

Pictured: A sign with the Merck logo surrounded by

Pictured: A sign with the Merck logo surrounded by

hapabapa/Getty Images

Two late-stage trial wins for Merck’s V116 investigational pneumococcal vaccine could make it a serious challenger to Pfizer’s Prevnar 20 in the space.

Pictured: Merck sign at its office in California/iStock, hapabapa

Merck’s investigational pneumococcal vaccine V116 aced two Phase III trials, eliciting strong immune responses in both the Phase III STRIDE-3 and STRIDE-6 trials, the company announced Thursday.

Without providing specific data, the drugmaker said that in STRIDE-3, V116 significantly outperformed the standard 20-valent pneumococcal conjugate vaccine at eliciting an immune response in adults who had not been immunized before.

Meanwhile, STRIDE-6 showed that Merck’s investigational shot could prime immunity against all 21 targeted pneumococcal serotypes in adults aged 50 years and above who had been vaccinated at least a year prior.

Both STRIDE-3 and STRIDE-6 also demonstrated that V116’s safety profile was comparable to the standard vaccine comparator used in these studies.

“Despite the availability of current pneumococcal conjugate vaccines, many adults remain vulnerable to pneumococcal disease, especially those who are older,” Merck Chief Medical Officer Eliav Barr said in a statement. “These results support the potential for V116 to become an important new preventative option for adults, regardless of prior pneumococcal vaccination status.”

V116 is designed to elicit immune protection against 21 serotypes that together account for 85% of invasive pneumococcal disease in older adults aged 65 years and above. The vaccine candidate could also be an important new preventative option for adults “by expanding coverage to include eight serotypes not currently included in any licensed vaccine,” Barr said.

Merck will share data from STRIDE-3 and STRIDE-6 in the future and use them to support V116’s regulatory bid, according to the company’s announcement.

Pfizer currently leads the pneumococcal vaccine space, with its Prevnar line of shots raking in nearly $6.4 billion in revenue in 2022, up 20% from the year before. This product family includes Prevnar 13 and Prevnar 20, respectively referring to pneumococcal vaccines targeting 13 and 20 serotypes of the Streptococcus pneumoniae.

In Pfizer’s first quarter 2023 earnings, it reported nearly $1.6 billion in revenue for the vaccine line, up 2% from the same period last year.

Merck, meanwhile, has lagged behind in sales. In 2022, Merck’s Vaxneuvance and its older pneumococcal shot Pneumovax 23 made a total of $772 million. Combined revenues for Merck’s vaccines in the first quarter of 2023 only totaled $202 million.

In April 2023, Pfizer expanded Prevnar 20’s label with an FDA approval allowing its inoculation in infants and children from six weeks to 17 years of age. In turn, this broader accessibility could lead to better sales numbers for the Prevnar products.

Merck has edged Pfizer out in this market, however, winning the FDA’s authorization to use Vaxneuvance in children in June 2022.

Tristan Manalac is an independent science writer based in metro Manila, Philippines. He can be reached at or

Tristan is an independent science writer based in Metro Manila, with more than eight years of experience writing about medicine, biotech and science. He can be reached at, or on LinkedIn.