The Importance of Phase-2 Clinical Research

The authors present a well-designed and executed Phase-2 clinical trial with the objective of evaluating the safety and preliminary efficacy of bezeotermin alfa in an autologous blood coagulum (ABC) carrier in patients with degenerative disc disease of the L3-S1 region undergoing lumbar interbody fusion surgery. The authors appropriately conducted this Phase-2 trial with the goal of expanding the Food and Drug Administration (FDA) label indications, currently used in anterior or lateral lumbar interbody fusion, to also include use in posterior or transforaminal lumbar interbody fusion (PLIF or TLIF). The Phase-2 study provided the necessary safety data and early efficacy data to support the rationale for a Phase-3 trial. The Phase-3 trial, which is underway, may lead to the expansion of the label to include this new indication. The phases of clinical trials, and the importance of each phase, are often not well understood. Due to this lack of understanding, Phase-2 research is often not published, or when it is published, it is highly criticized for methodological limitations inherent to the design. Briefly, a Phase-1 clinical trial is the first stage of testing a new drug, device, or treatment in humans1. It focuses on evaluating its safety, tolerability, and (if applicable) pharmacokinetics. These trials typically involve a small group of 20 to 100 healthy volunteers or patients, depending on the nature of the treatment. Investigators aim to determine the safe dosage range and identify side effects. While Phase-1 trials are not designed to test efficacy, they lay the groundwork for later phases by establishing whether the treatment is safe enough to proceed to a Phase-2 trial. The Phase-2 clinical trial represents an important stage in the development of a new drug, device, or treatment. Phase-2 trials are designed to assess the efficacy and evaluate the safety of a new drug, device, or treatment. Phase-2 trials typically have small sample sizes. These trials can be used to determine the optimal dosage and treatment regimen. Phase-2 trials are often placebo-controlled. Researchers monitor participants for therapeutic effects and side effects, using the data to refine the treatment protocol. If the results show efficacy and there are no safety concerns, the investigator may proceed to a Phase-3 trial. The Phase-3 trial includes a larger sample size and provides a more definitive conclusion regarding the efficacy and safety of the drug, device, or treatment being evaluated. Further evaluation as part of Phase-4 trials, which are often referred to as investigator-initiated trials, determines how the drug, device, or treatment works in real-world practice. As noted, Phase-2 trials represent an important step in evaluating new drugs, devices, and treatments. In addition, they can also offer an important step in evaluating off-label use of a drug or device. The bias against publishing Phase-2 research may stem from peer-reviewers of journals tending to favor more definitive Phase 3 or Phase 4 trials that are adequately powered to inform clinical decision-making and typically compare the treatment being evaluated to the current gold-standard treatment. While definitive conclusions cannot typically be reached from Phase-2 trials, they are still important to publish. If a Phase-2 trial identifies safety concerns with a drug, device, or treatment, or it does not demonstrate trends toward efficacy, off-label use should be reconsidered. Publishing the results of Phase-2 trials can also inform the development of future clinical trials within the broader scientific community. I am happy to see that JBJS has published the Phase-2 trial by Li et al., as it was well-designed and executed, and provides clinically meaningful results to the orthopaedic community. This Phase-2 trial found that bezeotermin/ABC was safe and well-tolerated during posterior-based single-level lumbar interbody fusion. The authors appropriately concluded that this preliminary efficacy of bezeotermin in accelerating spinal fusion and improving clinical outcomes supports its further clinical development. It is very important to publish high-quality Phase-2 trials, as they provide transparency and insight on patient safety, and can inform future research.