I think comments made by the trial investigators during the conference call that followed release of the 2b trial results shed some light on two of the issues you have raised. The transcript can be found on the company website.
I would have thought additional analysis of the Phase 2 trial data would allow them to identify higher probability responder groups.
Prof. Tim Jackson – Chief Investigator, Opthea Phase 2b wAMD trial
I think we have got the option as Pravin says, refining our case selection. But actually ... most trials as you move forward, you learn better the patients to target. And I would predict, this is a big enough study to learn a lot about which are the right patients to target. So, I think going forward, with the knowledge that we've gained from the study, from a fairly in depth analysis, if you had to make a prediction, my expectation would be a larger study would get a bit better vision knowing what we do now.
Dr Pravin Dugel – Principal Investigator, Opthea Phase 2b wAMD trial
…the other part that one should look at in terms of the phase three confidence is that with this large phase two study, we can analyse it in a post hoc manner, and then go ahead and study those patients in phase three that may have done particularly well. For instance, there may be patients in phase two that simply were recruited with vision that was very good that hit the ceiling, and simply couldn't improve any further. So learning those things from phase two, we can translate that into phase three, and then have an enhanced patient population….. You can really expect that Delta could be even greater and that should give us a great deal of confidence.
....if you make it too specific you exclude a large potential patient population from being treated. I note that in OPT documentation, they claim that half the patients using current medications do not achieve meaningful clinical outcomes. Imagine, if potential non responders could be tested and filtered out before being treated - there goes half the income!
Dr Pravin Dugel
I think what you would see is that this drug would be added on patients that were treatment resistant and we have lots of those patients, but certainly wouldn't be just confined to that. I think I would also look at patients that were treatment naive and say from the get go, "I'm going to go ahead and give you the very best combination I can in order to optimise your visual potential."
Prof. Tim Jackson
They were a very small proportion of patients who lost significant amounts of vision. So actually, it's harder to pick up on a signal like that. But interestingly, even though those small numbers of patients weren't driving the overall result, but the trend was definitely there, that there was not only improved vision gain but there was reduced vision loss. And I think that will be what plays out if this does get to market, that's what you're looking for. You're looking for a drug that can offer better vision, and that is making the earlier point in terms of what that means day to day for patients, but also looking to talk to those patients who otherwise are not doing well….
So I think that the trials tend to focus on treatment naive patients. That gives you, if you like, the purest data. So I think it's the right thing to do methodologically. But as we know from all the previous trials that the patients are tested on, the drugs are tested on treatment naive patients. But then they're often rolled out in the real world to previously treated patients. So I think, you know, almost certainly if this drug went to market, it wouldn't be reserved just for treatment naive patients. Like, you know, with certainty it would be used in the pool of patients who are already in the clinics. In terms of it being a particular useful drug for those who are not responding.
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