Let’s first be clear about one thing. As for any investigational drugs,
the safety of the drug is critically important as its clinical benefits. No
drug can be approved simply by its efficacy. If the risk (R) outweighs the
benefit (B), the drug cannot be approved. The key is the ratio or balance of
the two! Here is the tricky thing about the R/B ratio. There is a big
difference in how to assess the R/B ratio depending on the nature of drugs
under study. In general, the tolerability of risk is very low for drugs used for non-life-threatening diseases but the tolerability can be very high for
life-saving drugs such as cancer therapy. For most of the drugs, one or a
couple of deaths could easily kill the drug but for cancer drugs, deaths are
usually not that “a big deal” and you hardly see a promising cancer drug got
killed simply due to deaths or safety concerns. I think this can be easily understood.
If a patient is facing death already, would he or she care so much whether the
drug that could save his/her life may cause serious side effects or even death?
Hardly! This can also explain why practising doctors in the US are generally
facing a high risk of law suit but the risk is much less for oncologists even
so the drugs they use often kill patients prematurely. As such, as long as a
cancer drug has shown sufficient efficacy, the FDA will very unlikely kill the
drug just because a few deaths were reported. You can be sure that the company
will find a way to improve the safety profile and reduce the risk of fatality.
Just to give you a real world example what I mean for that. The very first
historical immunoonco therapy approved in the world, Yervoy (ipiliumumab for
melanoma) is a great drug that can save or prolong life of many patients with
this deadly cancer. But if you look at its label for the warnings, you will see
Yervoy can cause deadly side effects such as liver failure or colon perforation.
Yes, it is a challenge for the drug but certainly not a reason to disapprove it. That’s why I have much less concern about the fate of the CAR-T therapy
from JUNO due to the deaths reported. So how about the efficacy part? Well, it
is certainly premature to conclude this new therapy has no question about its
efficacy. Ultimately JUNO or other companies developing this class of therapy
must prove its clinical benefits. But here is the thing. We are not talking
about a drug that is still in the lab stage tested only in animals. This
therapy has shown quite promising efficacy in patients with advanced leukemia with 80-90% complete
response rate for the first year and more sustained response rate around 50%
after 2-3 years. Be aware these are the patients who have no available treatment options left and are close to death. You cannot find this kind of response rate if only due to a placebo
(fake) effect. To me this is very assuring evidence that the therapy is truly
working. Yes, the number of patients tested is quite small but this is under the orphan drug status and as such you don’t need a large number of
patients in clinical trials for approval.
Taking all together, I think the market is overreacting to the bad news
for JUNO as it typically does. It is definitely a setback for JUNO but so far I
haven’t seen any concern (from efficacy) that the product may get killed. Boy,
you don’t get a chance to buy a stock cheaply when everything goes very well as
planned. You only get this rare opportunity when a company is facing some
serious but temporary and solvable problems. I think
JUNO is just at this status at the moment. If you want to bet for this new technology,
the market offers you a great entry point. JUNO is currently working with the
FDA to revise the protocol and restart the study in probably less than 2
months. I suspect its share price will soon recover from its loss and may jump
as the clinical hold is lifted, barring unexpected new safety concerns emerge. I
bought more today!
No comments:
Post a Comment