The FDA recently granted a Breakthrough Therapy designation to AstraZeneca’s MEDI8897. Following several years of clinical development setbacks in the respiratory syncytial infections (RSV) field, MEDI8897 has the potential to offer substantially improved efficacy and cost effectiveness over existing RSV products, according to GlobalData, a leading data and analytics company.

MED18897 is an investigational monoclonal antibody (mAb) for the prevention of lower respiratory tract infections (LRTIs), caused by RSV in infants. The only approved medicine for RSV prophylaxis is AstraZeneca’s Synagis (palivizumab), a humanized mAb targeting the RSV fusion (F) protein.

Paul Jeng, PhD, Pharma Analyst at GlobalData, comments: “Synagis’ high price and restrictive label in US and European markets has largely limited its clinical applications. Synagis also has a relatively short half-life and requires monthly dosing during the RSV season, which presents a formidable barrier to patient compliance.”

AstraZeneca is positioning MEDI8897 as a direct successor to Synagis, with key improvements in efficacy and dosing, allowing a single injection to protect from serious infection through an entire RSV season. The commercial opportunity for prophylactic and therapeutic RSV products remains high, as several pipeline candidates have failed to hit their marks in clinical development. In 2017, Regeneron’s suptavumab (REGN222) was dropped from the development pipeline after a Phase III failure in healthy infants, and Johnson & Johnson recently suspended all clinical activities for its experimental RSV antiviral drug, lumicitabine, in 2018.

Although Novavax’s Phase III RSV F vaccine for maternal immunization may yet achieve approval, key opinion leaders (KOLs) interviewed by GlobalData believe that it will not be a silver bullet for RSV, as multiple prophylactic options may be required for the range of patient populations affected by RSV.

Since 2017, AstraZeneca has been developing MEDI8897 jointly with Sanofi, with the former helming development and manufacturing activities through initial approvals and the latter leading commercialization efforts. The two companies have plans to initiate a pivotal Phase III trial in the near future as a final step before reaching the market. In late 2018, AstraZeneca announced a deal to divest its US rights to Synagis to Swedish Orphan Biovitrum (Sobi) for $1.5bn, while establishing a profit or loss share agreement for MEDI8897 with the same company.

Jeng concludes: “In the context of recent positive clinical data, these commercial maneuvers strongly indicate that MEDI8897 will launch successfully and likely overtake and expand upon Synagis’ existing market share.”