Icky skin stuff = good? In relation to immunotherapy response for melanoma??

We know that folks on immunotherapy can develop all sorts of side effects. We know they are dose related (more medicine = more side effects), often cumulative, and can occur/continue after treatment has ceased. Here's a link:  More side effects than you ever wanted to know about!  These side effects can range from life threatening to simply irritating.  We know that the most common side effects to immunotherapy are fatigue, skin problems (rash and itching) and GI issues (diarrhea).  93% of folks taking the ipi/nivo combo will develop some level of side effects.  On ipi alone, 85% of peeps develop side effects.  While about 75% of folks on anti-PD-1 (nivolumab/Opdivo or pembrolizumab/Keytruda) as a single agent will develop side effects.  But what do these side effects mean apart from misery????

We have known for some time that the development of vitiligo secondary to immunotherapy for melanoma is a very good prognostic sign.  Here is more than you ever wanted to know on that topic:  All things vitiligo

We also know that skin related side effects for melanoma patients on immunotherapy can include a lot of things:  vague rash and itching, bullous lesions (blister like reactions like bullous phemphigoid), granulomatous skin reactions, sarcoidosis, the vitiligo previously mentioned and more.

In an article from 2015 researchers noted that "Survival analyses showed that patients who developed cutaneous AE's had significantly longer progression-free intervals in all 3 treatment dosage groups, compared to patients who did not develop cutaneous AE's." Here's the complete report: Itching and vitiligo associated with progression free survival after Pembro/Keytruda???!

Now, there's this:

Characterization of dermatitis after PD-1/PD-L1 inhibitor therapy and association with multiple oncologic outcomes: a retrospective case-control study. Min Lee, Li, Tran, et al. J Am Acad Dermatol. 2018 May 29.

Cutaneous adverse events are common with Programmed Death (PD)-1/ PD-Ligand (L)1 inhibitors. However, the nature of the specific cutaneous adverse event of dermatitis has not been investigated across various PD-1/PD-L1 inhibitors. Oncologic outcomes potentially associated with dermatitis are not well characterized.

To assess the nature of dermatitis after PD-1/PD-L1 inhibitor exposure and oncologic outcomes associated with dermatitis [we completed a]  Retrospective, matched, case-control study conducted at a single academic center.

The most common histologic patterns were lichenoid dermatitis (50%) and spongiotic dermatitis (40%). Overall tumor response rate was 65.0% for cases and 17.0% for controls. Progression Free Survival (PFS) and Overall Survival (OS) times were significantly longer for cases than controls by Kaplan-Meier analysis.  Retrospective design and relatively small sample size precluded matching on all cancer types.

Lichenoid and spongiotic dermatitis associated with PD-1/PD-L1 inhibitors could be a sign of robust immune response and improved oncologic outcomes. The predictive value of PD-1/PD-L1 related dermatitis on cancer outcomes awaits investigation through prospective multicenter studies for specific cancer types.

Here researchers report that folks on immunotherapy who developed dermatitis (skin irritation of varying degrees) had progression free survival and overall survival rates that were higher than those who did not, much like the data presented in the 2015 report above.

Perhaps these reports will bring some comfort to you rashed up melanoma peeps on immunotherapy!!! Since it is now 2018...let's figure out WHY!!!!  And make these results so for everybody! Hang tough.  - c