In Phase I oncology trials, the objective isn't "curative effects". Dosing isn't always consistent or even therapeutic; dosing may be varied to examine patient and cancer cell response. Essentially, these participants are enrolled for the collection of useful data, not because a high percentage are expected to go into remission (or any of them).
Put a little more simply, though not necessarily correct overview of how Trials work:
Phase I- small group of healthy volunteers (some trials use people with the disease studied). It's mainly to see the side effects that happen in people (as opposed to those that happened in animals).
Phase II- this is where a moderate sized group of people who are affected with a specific disease are given the drug at varying doses to measure the response
Phase III- This trial is huge. And it's across multiple centers. People are given a drug or something else (traditionally, you think of the 'something else' as a placebo, but as it would be cruel to treat a heart attack with a placebo rather than with the current standard of care therapy, therefore, depending on the situation, you can show efficacy vs placebo, or efficacy vs a specific treatment (typically the standard of care, otherwise you're setting up a tin man to knock down and your trial will show poor results).
In shortest, grossest terms, the stage that his drug is at is the "Let's see if it will kill people if they're given it for two weeks" stage.