Pneumococcal 7-valent conjugate vaccine(Pfizer Inc.)

Pfizer's paediatric vaccine reaches Phase 3 of trials. Credit: Pfizer Encouraging Phase 2 results show a robust immune response against serotype 3, prompting pivotal Phase 3 trials to protect up to 90% of paediatric patients Pfizer has announced the advancement of its pivotal paediatric pneumococcal vaccine programme following encouraging data from its Phase 2 clinical trial. The company has initiated its Phase 3 clinical trial for an investigational 25-valent pneumococcal conjugate vaccine candidate, designated PF-07872412 or 25vPnC, in infants. Alongside this milestone, Pfizer has unveiled plans to progress its adult vaccine strategy by moving straight to a fifth-generation 35-valent candidate. Strong immunogenicity shown in phase 2 results The decision to progress into a Phase 3 programme follows positive data from a Phase 2 study evaluating the safety, tolerability and immunogenicity of a four-dose series of the 25vPnC candidate in healthy infants. In this randomised trial, which began initial enrolment in July 2024, participants received either the 25vPnC candidate or the existing licensed standard-of-care vaccine, PREVNAR 20, at two, four, six and 12-15 months of age. Preliminary findings from the study were delivered during an oral presentation at the 14th meeting of the International Society of Pneumonia & Pneumococcal Diseases (ISPPD) in Copenhagen, Denmark. The results showed robust immune responses across all 25 included serotypes. Crucially, the investigational vaccine elicited an enhanced response against serotype 3, which continues to be a major cause of invasive pneumococcal disease and complicated pneumonia in young children. Data revealed that one month after the third dose, geometric mean titers for serotype 3 were 8.8-fold higher in infants given 25vPnC than in those who received PREVNAR 20, with scores of 4.22 versus 0.48 respectively. One month after the fourth dose, the gap widened further, with 25vPnC producing a serotype 3 immunogenicity response approximately 15-fold higher than PREVNAR 20, recording titers of 13.85 compared to 0.92. Broader disease coverage and safety The 25vPnC candidate builds upon the 20 serotypes already included in PREVNAR 20 by introducing five new serotypes: 15A, 23A, 23B, 24F and 35B. This addition expands protection to cover up to 90% of disease-causing serotypes in children under five years of age, representing an additional 25% coverage of invasive pneumococcal disease cases compared to PCV20. In terms of safety, the investigational vaccine was well-tolerated with no safety concerns identified during the Phase 2 study. The safety and tolerability profile remained consistent with currently approved pneumococcal vaccines, with the most common local reactions being typical injection site symptoms such as redness, swelling or pain. Annaliesa Anderson, Ph.D., Senior Vice President and Chief Vaccines Officer, Pfizer “For more than 25 years, our vaccines have helped protect children from pneumococcal disease, yet a significant disease burden remains,” said Annaliesa Anderson, Ph.D., Senior Vice President and Chief Vaccines Officer, Pfizer. “These Phase 2 results reinforce our confidence in a next-generation vaccine designed to expand protection across serotypes while improving responses to key residual disease drivers such as serotype 3. We are advancing our Phase 3 programme with the goal of delivering broader and more durable protection for children.” Launching the paediatric phase 3 programme Based on the robust immune responses observed across the Phase 2 programme and following collaborative discussions with regulatory authorities, Pfizer officially initiated its pivotal paediatric Phase 3 programme in May 2026. The company remains confident that the candidate will meet the necessary non-inferiority thresholds required in this definitive stage of testing. The upcoming Phase 3 studies will assess the safety, tolerability and immunogenicity of 25vPnC in up to 2,400 healthy children. Participants will be allocated to receive the exact same vaccine for all four scheduled doses, comparing 25vPnC directly to the licensed 20-valent standard-of-care vaccine at two, four, six and 12 to 15 months of age. Evolution of the adult vaccine strategy Simultaneously, Pfizer has chosen a direct pathway to maintain its long-term market leadership within the adult sector. The biopharmaceutical firm has decided to bypass intermediate clinical steps and move straight to a fifth-generation adult vaccine candidate that covers 35 serotypes. This adult candidate will leverage Pfizer's proprietary next-generation technology to enhance immunogenicity for critical strains, including serotype 3, while expanding overall serotype coverage. Pending alignment with regulatory authorities, this 35-valent adult vaccine candidate is projected to enter clinical development by the end of 2026. Company portals Pfizer Executives Annaliesa Anderson, Ph.D. Senior Vice President and Chief Vaccines Officer

With outbreaks of hantavirus and Ebola virus dominating the news, Pfizer vaccine chief Annaliesa Anderson, Ph.D., is traveling with face masks again for the first time in a while.\n After decades of developing vaccines to shield babies and adults from Streptococcus pneumonia infections, Pfizer is now taking another leap forward in its efforts to protect against one of the bacteria’s most dangerous strains—all while keeping an eye on the world’s several emerging global health threats.The pharma giant today shared data from a phase 2 study of its latest vaccine against Streptococcus pneumoniae, also called pneumococcus, which is designed to protect babies from 25 different variants of the pathogen.At the International Society of Pneumonia and Pneumococcal Diseases conference in Copenhagen, Pfizer revealed that its next-gen candidate—mellifluously named PF-07872412 or 25vPnC—produced stronger immune responses than the approved 20-variant vaccine Prevnar 20.Pfizer’s ultimate goal is to make a vaccine that hits 35 pneumococcus variants, known as serotypes, to cover 98% or 99% of all infections, the drugmaker’s vaccine R&D chief Annaliesa Anderson, Ph.D., told Fierce Biotech. But a leap from 20 to 35 serotypes takes time, and along the way the company realized that one variant in particular deserved special attention: serotype three.“Serotype three is a particularly serious serotype with high levels of associated morbidity and mortality,” Anderson explained. This variant causes 15% to 20% of infections, depending on the region, she said, and while Prevnar provides some protection against it, it doesn’t produce a strong enough immune response to halt community spread.Serotype three pneumococcus can invade the bloodstream and cause severe complications like pneumonia and meningitis, with fatality rates hitting as high as 47%.Pneumococcal vaccines work by generating antibodies that cling to the bacteria’s sugary surface. But serotype three’s sugars are thin and sparse, like a wire coat hanger that’s been straightened out, Anderson said, making it difficult to target.Pfizer recognized this challenge even before Prevnar 20 was licensed, she added, and the company put together an internal team of immunologists, bacteriologists and vaccine engineers to craft a solution. The team was able to assemble a “toolbox” of proteins that could effectively bind to serotype three’s bony sugar skeleton.In another presentation at the same conference, given yesterday, Pfizer pitted its next-gen serotype three approach against past attempts in adults and found it to be superior.But with 25vPnC now passing muster in infants, Pfizer is tightening the candidate’s focus all in the name of time. While a phase 3 trial in babies kicked off earlier this month, the pharma has decided to focus on its 35-variant candidate for adults instead.“Adult vaccines take less time to develop because you\'re not waiting for the baby to take all four vaccines and grow to a certain age,” Anderson said, which can take 12 or 18 months. “And we\'re not going to enroll all those babies overnight.”Because moving a 35-variant candidate forward in babies would take so long, the company is still advancing 25vPnC in order to get serotype three protection to the little ones as quickly as possible.Pneumococcus “used to be one of the most common diseases out there for babies, and now it\'s not,” Anderson said. “We want to keep it like that.” Head down Though anti-vaccine sentiment is currently dominating U.S. health agencies, Anderson is keeping her focus on the things she can control—ensuring Pfizer has a strong, science-backed portfolio of vaccines moving ahead.“Parents like to protect their babies,” the vaccine leader told Fierce. “The pneumococcal vaccines have got an incredibly safe safety profile. They\'re used all over the world.”Pfizer’s history in the field runs deep. Wyeth, which Pfizer acquired in 2009 for a whopping $68 billion, released its first pneumococcal vaccine—effective against seven variants of the bacteria—in 2000.Aside from working to subdue pneumococcus, Pfizer’s vaccine programs straddle very early-stage efforts as well as late-stage candidates meant to tackle areas of huge unmet medical need. That includes a shot for Clostridium difficile infection that failed a phase 3 trial in 2022 in adults 50 or older, which Pfizer is now pursuing in a narrower group of adults aged 65 and up.Another vaccine for Lyme disease also missed in phase 3 earlier this year, which Pfizer and partner Valneva attributed to lower-than-expected cases of the tick-borne illness. The pharma still plans to push ahead with an approval effort. Like pneumococcus, C. diff and Borrelia burgdorferi, which causes Lyme disease, are both bacteria.“They all meet unmet medical needs, and they\'re all critical,” Anderson said of these investigational immunizations. But she’s also excited by Pfizer’s continuing work in established disease areas like respiratory syncytial virus and COVID-19, which forms the other pillar of the company’s vaccine portfolio.But fighting infectious diseases is like playing Whack-A-Mole, with new threats popping up at an ever-increasing pace. Anderson is keenly aware of the new pathogens now dominating the news cycle, a hantavirus outbreak on a cruise ship and an Ebola epidemic in central Africa, now labeled a public health emergency of international concern by the World Health Organization.Both of the viruses in question, the Andes virus species of hantavirus and the Bundibugyo species of Ebola virus, currently lack vaccines.As the maker, along with partner BioNTech, of the first mRNA vaccine for COVID-19, Comirnaty, Pfizer is not hesitant to pitch in when health crises emerge, Anderson told Fierce.“We keep an eye on what\'s going on out there, and if public health emergencies happen, we are certainly comfortable to step in and see where we can help,” she said.Her concern is evident, she added, if one looks through the luggage she packed for her trip to Copenhagen for the conference. For the first time in a while, she made sure to bring face masks.