Rare but Meaningful Efficacy Findings in Phase I Oncology Trials

A Phase I trial for a cancer treatment is, almost by definition, emotionally loaded territory. Unlike other Phase I trials, which test a new treatment on healthy volunteers, cancer trials involve patients who are presently battling the type of cancer the treatment is designed to target1. What’s more, a typical participant in these trials has already exhausted all standard treatments available outside of a clinical setting, to no avail. For these people, the trial represents their last chance; they are facing their own mortality and have few or no other options. From the researchers’ perspective, things are a little different. A Phase I cancer trial aims to test the body’s reaction to a new treatment, but with safety and side effects in mind–not efficacy. Like other Phase I trials, researchers have not yet begun to focus on whether a drug shows signs of effectiveness in combating the disease.

This doesn’t mean, though, that unanticipated efficacy findings don’t occasionally occur in Phase I of a cancer trial. And when they do, given the desperation that often characterizes the body of participants, it can feel like a miracle.

Hope for patients, optimism for oncology

Consider two recent cases: In a Phase I study in Canada and Texas, a drug has shown promise in halting, or even reversing, tumor growth2. And in Ohio, a 74-year-old man, after being diagnosed with stage IV lung cancer, was persuaded by his doctor to enroll in a Phase I trial whose treatment, the man says, may have saved his life: one of his two tumors has disappeared, and the other has stopped growing3. Such findings are cause for optimism not just for the patients that were treated in these studies, but in the ongoing fight against cancer in general. And they’re all the more exciting, as well as surprising, for having come out of the first Phase of clinical trials for cancer treatments.

Of course, Phase I efficacy findings should be taken with a grain of salt. Even if a drug demonstrates effectiveness in slowing the growth of a tumor, a patient’s cancer may, sadly, be too advanced for the treatment to push it into full remission. And the body of participants in a Phase I trial may be too small to confidently conclude that a treatment is effective in combating cancer in the general population; later phases, of course, must still be carried out. Still, such results are exciting: they can offer new hope to people in their most dire moment, and be a valuable, if unexpected, lead for the medical research community.

Phase I cancer trials are unique in their involvement of extremely sick and vulnerable patients, but aligned with other Phase I trials in their focus on general physiological response instead of efficacy. When efficacy is nonetheless demonstrated, then, it can be a pleasant, and potentially life-saving, surprise.

1 Phases of Clinical Trials; Cancer.Net; December 2015
2 Tower, Katie; Soricimed encouraged by results from first phase of clinical trials; Sackville Tribune-Post; 3/1/16
3 Pence, Katie; Patient Attributes Phase 1 Clinical Trial, Research to Keeping Him Alive; University of Cincinnati; 3/1/16