Infection and Drug Resistance | Volume 15 - Dove Press Open ...

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

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 tristan@tristanmanalac.Com or tristan.Manalac@biospace.Com.

Merck's Investigational Pneumococcal Vaccine Shows Promise In Older Adults

Merck & Co – known as MSD outside the US and Canada – has shared positive results from two late-stage trials evaluating its investigational 21-valent pneumococcal conjugate vaccine in adults.

Pneumococcal disease is the name for any infection caused by bacteria called Streptococcus pneumoniae and is considered a "major public health problem worldwide" by the World Health Organization.

There are more than 100 different types of pneumococcal bacteria, which can affect adults differently than children. Highly aggressive strains threaten to put more people at risk for invasive pneumococcal illnesses, Merck reports, and older adults are among those most vulnerable to serious infection.

Merck's candidate, V116, is specifically designed to address the strains that represent adult pneumococcal disease, including eight unique strains which account for approximately 30% of adult disease.

If approved, V116 would be the first pneumococcal conjugate vaccine specifically designed for this patient population, according to the company.

Results from the phase 3 STRIDE-3 trial, which has been evaluating V116 in vaccine-naïve adults, demonstrated statistically significant immune responses compared with Pfizer's 20-valent vaccine, Prevnar 20, for strains common to both vaccines as well as those unique to V116.

Additionally, results from the phase 3 STRIDE-6 trial demonstrated that V116 was immunogenic for all 21 pneumococcal strains in the vaccine among adults who had received a pneumococcal vaccine at least one year prior to the study.

V116 had a safety profile comparable to the comparator in both studies, Merck said, adding that the results will now be shared with the scientific community and will support global regulatory applications.

Dr Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories, said: "Despite the availability of current pneumococcal conjugate vaccines, many adults remain vulnerable to pneumococcal disease, especially those who are older.

"These results support the potential for V116 to become an important new preventative option for adults, regardless of prior pneumococcal vaccination status, by expanding coverage to include eight serotypes not currently included in any licenced vaccine."

Investigational 21-Valent Pneumococcal Conjugate Vaccine Immunogenic, Safe

Merck's investigational 21-valent pneumococcal conjugate vaccine, V116, elicited positive immune responses in vaccine-naïve and previously vaccinated individuals, according to results from two phase 3 trials.

The randomized, double-blind, active comparator-controlled STRIDE-3 (ClinicalTrials.Gov Identifier: NCT05425732) and STRIDE-6 (ClinicalTrials.Gov Identifier: NCT05420961) studies evaluated the safety and immunogenicity of V116 in pneumococcal vaccine-naïve adults 18 years of age and older (n=2600) and adults 50 years of age and older who previously received a pneumococcal vaccination at least 1 year prior to study enrollment (n=717), respectively. 

In STRIDE-3, patients were randomly assigned to receive 1 dose of either V116 or PCV20 (pneumococcal 20-valent conjugate vaccine). In STRIDE-6, patients were randomly assigned to receive 1 dose of either V116, PCV15 (pneumococcal 15-valent conjugate vaccine), or PPSV23 (pneumococcal vaccine, polyvalent [23-valent]). 

Among vaccine-naïve adults in STRIDE-3, V116 demonstrated statistically significant immune responses compared with PCV20 for serotypes common to both vaccines, as well as positive immune responses to serotypes unique to V116 (Streptococcus pneumoniae serotypes 15A, 15C, 16F, 23A, 23B, 24F, 31 and 35B), as assessed by serotype-specific opsonophagocytic activity 30 days postvaccination. Moreover, findings from STRIDE-6 showed that V116 was immunogenic for all 21 pneumococcal serotypes (S. Pneumoniae serotypes 3, 6A/C, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B/C, 16F, 17F, 19A, 20, 22F, 23A, 23B, 24F, 31, 33F, 35B) in adults who previously received pneumococcal vaccination at least 1 year prior to the study. The safety profile of V116 was comparable to the comparators in both studies.

"Despite the availability of current pneumococcal conjugate vaccines, many adults remain vulnerable to pneumococcal disease, especially those who are older," said Dr Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. "These results support the potential for V116 to become an important new preventive option for adults, regardless of prior pneumococcal vaccination status, by expanding coverage to include 8 serotypes not currently included in any licensed vaccine."

V116 was previously granted Breakthrough Therapy designation by the Food and Drug Administration for this indication.

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