Ouch! Pfizer terminates S. aureus vaccine trial due futility

Addendum: This is the third in a 3-newsletters series on this topic. Go here and here for the prior newsletters.

Dear All:

Per a press release today:

  • Pfizer Inc. (NYSE:PFE) announced today that the Phase 2b trial STRIVE (STaphylococcus aureus SuRgical Inpatient Vaccine Efficacy) evaluating the company’s investigational Staphylococcus aureus (S. aureus) multi-antigen vaccine (PF-06290510) is being discontinued due to futility. This decision is based on a recommendation from an independent Data Monitoring Committee (DMC), composed of external experts, after conducting a pre-planned interim analysis.
  • The DMC concluded from these data that the study reached futility, meaning that there is low statistical probability for the study to meet the pre-defined primary efficacy objective in adults undergoing elective spinal fusion surgery after completing a planned Phase 3 expansion of the study.
  • A safety review by the DMC indicated that the investigational vaccine has been safe and well tolerated. STRIVE trial participants who are enrolled in the study will complete the study’s follow-up evaluations.
  • Pfizer is evaluating next steps for the potential development of a S. aureus vaccine

I am so sorry to read this … I had thought this a very strong effort. Details are limited but as a “safety review by the DMC indicated that the investigational vaccine has been safe and well tolerated,” the problem must have been that it was not going to be possible show a reduced infection rate over placebo.

Recall that this vaccine was the subject of a 7 Nov 2017 FDA VRBPAC meeting during which questions about whether (and how) such a vaccine could be developed for general use (go here for the materials from that meeting). As a reminder,

  • Pfizer identified elective open, posterior approach, multilevel, instrumented, spinal fusion surgery (read that carefully) might have a sufficiently high rate of post-operative infections (estimated at 1.44%) despite best prevention methods that the effect of a vaccine could be measured by studying (only!) 3000-6000 subjects.
  • By contrast, a study in another elective orthopedic surgical population (e.g., hip arthroplasty) similar in design to STRIVE would take >10 years to complete and would require enrollment of 20,000 to 40,000 subjects.
  • The AC thus focused on the question of whether (how) the results from one trial could generalize to other settings.
  • I’ll also remind you of the recent Wellcome-sponsored report on antibacterial R&D opportunities which placed a S. aureus vaccine at the mid-point of difficulty:

Picture

Deep sigh … we always knew vaccines were hard but something for S. aureus would be so valuable. There have been multiple prior failed efforts (Fowler & Proctor, CMI 2014) to create such a vaccine and Team Pfizer should be congratulated for giving this another serious try. I hope they will soon share their analyses on why this vaccine failed so that other work can be guided by their efforts. 

“My strength lies solely in my tenacity.” Louis Pasteur

Onward! All best wishes, –jr

John H. Rex, MD | Chief Medical Officer, F2G Ltd. | Expert-in-Residence, Wellcome Trust. Follow me on Twitter: @JohnRex_NewAbx. See past newsletters and subscribe for the future: http://amr.solutions/blog/

Upcoming meetings of interest to the AMR community:

  • 15 Jan 2018 (London): BSAC’s Antimicrobial Chemotherapy Conference 2019: “An ABC for everyone involved in developing new antimicrobials.” Details here.
  • 29 Jan 2018 (REVIVE webinar): “Clinical development for non-developers Part 3: 
    Antibacterial Drug Enhancer Combinations and Non-traditional Products.” Register here.
  • 4-5 Feb 2019 (London): Hamied Foundation UK-India Antimicrobial Resistance Meeting 2019. This is a 2-day meeting focused on building research links between the UK and India with the specific aim of jointly addressing the challenge of AMR. Register here.
  • 14-15 Mar 2019 (Berlin): BEAM-, CARB-X-, and ND4BB-ENABLE-sponsored Berlin Conference on Novel Antimicrobials and AMR Diagnostics. Details here.
  • 21-22 Mar 2019 (Birmingham, UK): BSAC Spring Conference.
  • 26 Mar 2019 (London, UK): Sponsored by The Economist, a 1-day symposium entitled “Antimicrobial Resistance: Preventing an antibiotic apocalypse.” Register here.
  • 13-16 Apr 2019 (Amsterdam): Annual ECCMID meeting.
  • 24-26 Apr 2019 (Boston): Annual SHEA (Soc. for Hospital Epidemiology of America) Spring meeting
  • 6-11 May 2019 (Ljubljana, Slovenia): 37th Annual Meeting of the European Society for Paediatric Infectious Diseases (ESPID). Details here.
  • 3-6 Jun 2019 (Philadelphia): Annual BIO meeting
  • 20-24 June 2019 (San Francisco): Annual ASM Microbe meeting.
  • [Mark your calendar now!] 3-6 Sep 2019 (Boston). Annual ASM-ESCMID Conference on Antibiotic Development. The Bootcamp series will continue on 3 Sep with the main meeting on 4-6 Sep. Mark your calendar now and check back here for details.
  • 6-8 Sep 2019 (Bilbao, Spain): 5th ESCMID conference on Vaccines. Check back here for details.
  • 2-6 Oct 2018 (Washington, DC): IDSA’s annual IDWeek meeting.
  • 19-27 Oct 2019 (Annecy, France): International Course on Antibiotics and Resistance (ICARe) – A soup-to-nuts intensive residential training program on all things AMR, especially R&D for new antibiotics. See this link for details.

Share

Leaky pipe(line)s, Part 2 / CARB-X reboot / WHO 2021 pipeline review

Dear All, We have a 3-part discussion today on the theme of “I want a new drug … so how do I find it?” Off we go! First, the 14 June 2022 newsletter entitled “Leaky Pipe(lines) / When Is A Molecule A Drug” generated further discussions that are worth sharing: It was noted the microdosing

Antibiotic procurement models for LMICs / G7 Leaders call for Pull!

Dear All, Two stops on our tour today: (i) an excellent survey of incentive models and (ii) a final communique from the recent G7 meetings. First up, CGD (Center for Global Development) have released a report (link) entitled “Leveraging Purchasing Systems to Ensure Access, Stewardship, and Innovation: A Landscape Review of Current and Potential Market Structures

Leaky pipe(lines) / When is a molecule a drug? (Part 1 of 2)

Dear All, I was fascinated by this recent paper in AAC: Neha K. Prasad, Ian B. Seiple, Ryan T. Cirz, and Oren S. Rosenberg. Leaks in the Pipeline: a Failure Analysis of Gram-Negative Antibiotic Development from 2010 to 2020. Antimicrob Agents Chemother. 2022 May 17;66(5):e0005422. doi:10.1128/aac.00054-22. (Addendum: This newsletter has a follow-up newsletter.) In brief,

FDA/CVM: Antimicrobial use in companion animals

Dear All, Post-newsletter addendum: I’ve learned that USDA will host a 10 Aug 2022 (virtual, 10a-4.30p ET) workshop on AMR in food agriculture. See the meetings calendar for more details; go here to register. I’ll confess to having missed entirely the request back in February 2022 from FDA’s Center for Veterinary Medicine (CVM) for comments on antimicrobial

Scroll to Top