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For patients diagnosed with Periprosthetic Joint Infection

The APEX-2 Clinical Trial

The APEX-2 clinical trial is studying a rapid 7-day treatment for PJI of the hip or knee using VT-X7. Patients who qualify and decide to enroll in the trial will be randomly assigned to treatment with either VT-X7 or standard two-stage exchange surgery. Patients have equal chances of receiving VT-X7 or standard treatment but will not be told which treatment they received until they awake from the first surgery. 

What is PJI?

Periprosthetic joint infection (PJI) is a rare but serious complication after joint replacement surgery. PJI occurs when bacteria grow around your artificial joint, causing pain and swelling. Typically, these infections occur within five years of joint replacement surgery but can happen at any time. If left untreated, PJI can lead to amputation of the infected limb or even death. 
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What is Standard Treatment for PJI?

Your doctor may have recommended two-stage exchange arthroplasty (surgery) to treat your PJI. This involves removing the infected artificial hip or knee (stage 1), treating the infected tissue and bone with antibiotics, and implanting a new artificial joint (stage 2). Eliminating the infection requires intravenous (IV) antibiotics and placement of a temporary spacer that slowly releases antibiotics. After confirming the infection is gone, the surgeon will implant a new artificial joint. The total treatment time is typically about 16 weeks.

Standard Two-Stage Surgery

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Stage 1: Remove Infected Implant

  • Surgery to remove the infected implant
  • Insert temporary spacer containing antibiotic powder

Standard Treatment  

  • Intravenous antibiotics for at least 6 weeks
  • Surgeon watches for ongoing infection

Stage 2: New Permanent Implant

  • Surgery to remove the spacer and implant a permanent joint replacement

Rapid Two-Stage Surgery

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Stage 1: Remove Infected Implant

  • Surgery to remove the infected implant
  • Insert a VT-X7 titanium spacer

VT-X7 Treatment 

  • Antibiotics irrigated through the infected joint space for 7 days

Stage 2: New Permanent Implant

  • Surgery to remove VT-X7 spacer and implant a permanent joint replacement

What is VT-X7?

VT-X7 is a drug-device combination that delivers high concentrations of vancomycin and tobramycin, well-established antibiotic drugs, directly to the infected joint space.  When used as part of a two-stage exchange arthroplasty procedure, VT-X7 has the potential to significantly lower treatment time and improve success rates.
VT-X7 is an investigational product. Limited by federal law to investigational use.
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How does it work?

VT-X7 works by directly delivering antibiotics to the site of infection which means the bacteria infecting the joint are exposed to higher sustained concentrations.

Flushes the Joint Space
with Antibiotics

150+ Times
in 7 Days

Expected Advantages of VT-X7

  • Antibiotic concentrations at the infection site sufficient to penetrate biofilm
  • Effective against gram-negative and gram-positive organisms
  • Low antibiotic serum concentrations
  • Infection is treated and patient receives new revision prothesis in 7 days
  • Durable results: >90% of patients are infection free at 1 year post treatment

Is APEX-2 right for you?

Talk to your doctor about enrolling in the APEX-2 clinical trial if you say YES to the following statements:​
  • I have been diagnosed with periprosthetic joint infection (PJI).
  • I have been told I need two stage exchange surgery. 

Can I choose VT-X7?

VT-X7 is an investigational product limited by US law to investigational use only. It is not available for sale and cannot be offered outside of the APEX-2 trial. 

Successful Phase 2 Results

Osteal Therapeutics conducted a Phase 2 prospective, single-arm, clinical trial for the treatment of patients with infected hip and knee prostheses at 4 U.S. centers. In the trial all subjects received new revision joint prostheses after 7 days of therapy and a clinically and statistically significant percentage of subjects were infection free at 12 weeks and 1 year.

Find a location

Sponsors and Collaborators

Osteal Therapeutics®
Osteal Therapeutics® is a privately-held, clinical-stage pharmaceutical company developing novel musculoskeletal therapeutics to treat orthopedic infections and their consequences.
Osteal Therapeutics employs a low risk development strategy by improving delivery of pharmaceuticals with long histories of safety and efficacy.
The company is lead by a highly experienced team of orthopedic industry veterans supported by world-class clinical partners.
Learn More
For more information about ongoing clinical trial of VT-X7, visit
Protocol OTX-0302
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