The first two Phase two trails for the pain drug Z160 are over. We know that because the last patients to enter were already in the trials before September 3rd and the trial design is for six weeks. Right now the results are being calculated. We'll know the results very soon.
How will success be PRIMARILY measured? (They are a number of secondary endpoints, but the market is going to look at whether or not the studies met their PRIMARY or first or top goal.)
In the low pack pain (Lumbosacral Radiculopathy or LSR) study they will be looking for improvement in the average DAILY self-reported pain scores of the patients getting Z160 WHEN COMPARED TO PLACEBO.
In the after shingles pain (Postherpetic Neuralgia (PHN) study they will be looking for improvement in the average WEEKLY self-reported pain scores of the patients getting Z160 WHEN COMPARED TO PLACEBO.
Without going into the math* here's what will define success. Because of the size of the groups being studied, to say with acceptable confidence that the effects we're looking for are not chance we would want to see a 30% or better improvement in self-reported pain scores from the base line scores at the beginning of the study. COMPARED TO PLACEBO.
No other comparison will be considered.
Neither of these studies will involve ANY comparison to ANY other pain drugs at this stage. Why? Because none of those other drugs are being taken by patients in this current study. So those comparisons would have to be HISTORICAL COMPARISONS, which would not be considered valid here. Why is that? Because those data about other drugs were collected in a DIFFERENT setting by DIFFERENT doctors and were compared against a DIFFERENT placebo group.
Any suggestion that Z160 will be compared at this time against existing pain drugs is just uninformed misinformation. Ignore it.
*(if you want to do that yourself, a good article to search for is "Making Sense of Pain Research Part 10 – Interpreting Effect Sizes in Research Data
Good point on trial design. COMPARED TO PLACEBO. I like the design to give positive results, but I thought the standard of care was supposed to always be given. Is it ethical to have people in pain on a placebo.
i have to give credit to the patients that actually sucked it up and rolled off other pain meds to enroll/be eligible for the trial... thanks for the detailed post - is it bad i'm an accounting degree and probably know more about science just by following biotechs the past 3 years ...lol
Post-shingles nerve pain (PHN) fluctuates a lot more than lower back pain. Daily changes in shingles pain might not be meaningful and could confound results. Weekly pain score changes will tell a clearer story there. It's a smart design.