Upcoming events – Data from Pfizer’s staph vaccine and Agile’s contraceptive

Welcome to your weekly digest of approaching regulatory and clinical readouts. By the end of the year Pfizer could report an interim analysis from a phase IIb trial testing its Staphylococcus aureus vaccine. PF-06290510 is being studied in patients undergoing spinal surgery. As an incredibly tough infection to crack the market remains untapped for now.

Also coming before the end of the year are topline phase III results with Agile’s contraceptive Twirla. The FDA rejected the drug three years ago requesting more data, and as Agile’s lead product another setback would be a blow for the company. 

Valuable vaccine

The phase IIb Strive trial is testing PF-06290510, a Staphylococcus aureus vaccine, versus placebo in 2,600 patients undergoing elective spinal surgery. The vaccine is given once intramuscularly 10 to 60 days before surgery.

The primary endpoint is the number of patients with postoperative S aureus blood stream infections and/or surgical site infections within 90 days after surgery. Safety and tolerability are also primary measures.

The vaccine was given fast track designation in 2014 and the company has previously said the trial would be registrational.

Phase I/II data in healthy volunteers showed that PF-06290510 was well-tolerated and produced a rapid rise in in antibodies against S aureus that were maintained through at least 12 months.

Resistant S aureus has become a significant health problem and is mostly acquired in hospitals and nursing homes. It causes a range of issues from mild skin infections to deep wound and surgical site infections, bacteraemia and sepsis, potentially leading to death.

The rates of hospital onset severe MRSA infections are falling in the US according to data from the CDC, due to improved prevention strategies – although it is still a significant financial burden with over 80,000 invasive MRSA infections and over 11,000 related deaths per year in the US.

Efforts to develop an effective S aureus vaccine have been tough. Notably Intercell’s V710 showed lower mortality in the placebo arm than those given the vaccine in a phase II/III trial in patients scheduled for cardiothoracic surgery. Also Nabi Biopharmaceuticals’ StaphVax failed a confirmatory phase III trial in haemodialysis patients. 

Pfizer’s PF-06290510 is said to target S aureus more broadly as a four antigen vaccine or SA4Ag. Previous effort V710 was a monovalent vaccine while StaphVax was bivalent.

According to consensus from EvaluatePharma sales of PF-06290510 are forecast to reach $489m by 2022. With an NPV of $1.8bn this makes it the fifth most valuable phase II product and Pfizer’s seventh biggest growth driver. Leerink analysts however warn of market fragmentation, as the vaccine may only be given prior to specific procedures or to “high-risk” populations.

Second time lucky?

Agile Therapeutic’s Twirla is a once weekly contraceptive patch. The phase III Secure trial is in 2,100 women receiving Twirla for up to one year. The primary endpoint looks at pregnancy rates and top line data are expected in the fourth quarter.

Before Agile went public the FDA planted a complete response letter on its doors back in 2013. The regulators requested additional clinical data, quality and CMC information. A year later the New Jersey based company floated at a 54% haircut, raising $55m. Resubmission is expected in the first half of next year.

According to consensus from EvaluatePharma 2022 sales are forecast to reach $490m with an NPV of $341m, 162% the company’s market cap. As of the end of June the company had $59.2m in cash, enough to fund it through to the end of next year. Twirla is Agile’s lead pipeline product, and with its shares off 25% this year it will have fingers crossed the data will satisfy the regulators this time.


The Europen Society for Medical Oncology congress is taking place October 7-11 in Copenhagen, Denmark. Check out our preview and free backgrounder highlighting recent breakthroughs, setbacks and approaching data points.

Product Trial
PF-06290510  Strive NCT02388165
Twirla Secure NCT02158572

To contact the writer of this story email Joanne Fagg in London at joannef@epvantage.com or follow @JoEPVantage on Twitter

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