On September 13, GlaxoSmithKline (GSK) announced that the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted unanimously to recommend the approval of its investigational vaccine, Shingrix (zoster vaccine, recombinant [adjuvanted]), for the prevention of herpes zoster (HZ) in adults ≥50 years of age.
A final decision on the approval of Shingrix is expected on or before the product’s October 16, 2017 Prescription Drug User Fee Act (PDUFA) date. Upon its licensure, GlobalData expects Shingrix to immediately challenge Merck’s Zostavax (HZ vaccine, live-attenuated) for dominance of the global HZ vaccine marketplace.
Known more commonly as shingles, HZ affects approximately 1 million people annually in the US alone, 30% of which develop postherpetic neuralgia (PHN), pain lasting from at least three months up to several years. One in three Americans will experience HZ in their lifetime, with one of every two adults ≥85 years of age suffering from shingles. Given the high level of morbidity associated with HZ and PHN, improved preventative interventions remain an important unmet medical need.
The VRBPAC’s enthusiastic endorsement of Shingrix was based on strong efficacy and safety data obtained from two pivotal Phase III trials (ZOE-50 [NCT01165177] and ZOE-70 [NCT01165229]), which demonstrated the efficacy, immunogenicity, and safety of a two-dose series of Shingrix in 16,160 adults ≥50 years of age and 14,800 adults ≥70 years of age, respectively.
The results obtained from ZOE-70 are particularly compelling, as the vaccine protected 89.8% of recipients from HZ over a mean follow-up period of 3.7 years (95% confidence interval [CI], 84.2–93.7; P < 0.001) when compared with placebo. Shingrix’s durable effectiveness in adults ≥70 years of age represents a substantial improvement over Zostavax, which is currently the only vaccine approved to prevent HZ.
Another important advantage Shingrix possesses is its ability to be administered to immunocompromised patients—as a live-attenuated vaccine, Zostavax is contraindicated in these patient populations, which include those being prescribed immunosuppressive agents to treat a myriad of diseases ranging from cancer to gastrointestinal and inflammatory disorders. The patients who cannot receive Zostavax are also those at the highest risk of contracting shingles, so GlobalData expects Shingrix to be welcomed by clinicians eager to protect their patients from this debilitating disease.
Recognising the serious threat posed by Shingrix, Merck has employed an aggressive marketing campaign in the US, primarily in the form of direct-to-consumer (DTC) advertising and physician education initiatives, in order to increase the uptake of Zostavax over the past 6–12 months.
Despite Merck’s efforts to better position Zostavax, GlobalData believes that Shingrix’s strong clinical profile will allow it to quickly garner market share in a potentially $1 billion space following its anticipated approval by the FDA in the upcoming weeks. Nevertheless, GSK’s vaccine must still receive endorsements from national immunization committees, such as the Center for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices (ACIP), in order to guarantee its widespread use post-approval.