Staying on Keytruda - NED - 1294223

Hi hherpel,

Welcome to GRACE. The question you pose is one that is very difficult to answer. There are no definitive answers at this point, and the problems involved in trying to establish an optimal duration of immunotherapy were discussed by Dr. Eddie Garon of UCLA here. The CheckMate 153 trial mentioned by Dr. Garon is estimated to conclude in January, 2022.

This situation is analogous to that of the small but not insignificant subset of EGFR- or ALK-positive NSCLC patients who are NED after an extended period of well-tolerated targeted therapy. Should treatment continue indefinitely? In those situations, the only way to find out is to stop therapy and monitor for recurrence. But if we're talking about a period of several years, many of those patients have dropped off the radar of any clinical trial. In addition, if a trial determined that two-thirds (or any other percentage) of patients who cease therapy after three years (for example) never recur, would that be strong enough data to lead a patient to stop treatment?

At some point, testing for cancer cells may be sophisticated enough to determine whether any cancer cells remain in the body, but we aren't there yet.

Sending good thoughts for continued success with nivolumab.

JimC
Forum moderator

Hi hherpel,

It's good to hear about NED and I hope it lasts. To add to Jim's always excellent comment is a post from Dr. West that unfortunately doesn't answer your question but does give excellent info that surrounds the question.
http://cancergrace.org/cancer-101/2016/09/14/io-duration/

Best of luck,
Janine

Thanks for this thread hherpel, and for all of the info Janine and Jim.

Duration of treatment is also identified as one of the areas for future research in this publically available 2018 review paper "Development of PD-1 and PD-L1 inhibitors as a form of cancer immunotherapy: a comprehensive review of registration trials and future considerations"

https://jitc.biomedcentral.com/track/pdf/10.1186/s40425-018-0316-z

For those who are interested in looking into this issue further.

I just wanted to add what may be an obvious note about what we know about breaking from treatment of pd 1 and pd l1 inhibitors. Most of the info comes from those who were forced to stop effective treatment because of side effects of the treatment. So there have been those who have done very well with durable remission type periods of stable and or NED disease control. This is very promising however without more substantial data we don't know if disease control is from indolent cancer that would have done well no matter the treatment or lack of tx. Or maybe there is a subset of nsclc that has a durable response to a short term immuno tx but who is that.

In my previous post's link Dr. West outlines his current thought process when treating with immunotherapies, "In the meantime, we are left to our best judgment, and different oncologists follow different approaches. Some continue immunotherapy without any break, as long as a patient is doing well. Others stop it after a fixed period, whether that is 6 or 12 or 24 months or some other one — we don’t have an evidence-based endpoint. The approach I tend to favor is one in which I discuss the options with the patient, who may have a personal preference, but I recommend increasing the interval between treatments starting around 6 months in, gradually increasing from 2 or 3 to longer intervals of 4-6 weeks for the next year, then eventually out to 6-8 weeks. This is based on a principle that the immune system may benefit from a “refresher” repeat stimulation intermittently, but treatment every 6-8 weeks is a much more convenient interval of follow up than a shorter one, and this reduces cumulative exposure and risk of side effects, while also reducing cost of treatment. However, if a patient has significant side effects or a clear preference to stop, I would be far more inclined to hold treatment and follow the patient and their scans closely, leaving open the option of resuming immunotherapy later."