After stopping anti-PD1 treatment...how long can melanoma patients maintain a complete response????

One of the many million dollar questions in melanoma is:  How long should I take anti-PD1 products (nivo or pembro)?  And..... If I stop after a complete response, will I be able to maintain that response?  Here is a report from a study (IN ITS EARLY DAYS!!!!!) looking at just that question....

The cessation of anti-PD-1 antibodies of complete responders in metastatic melanoma. Ladwa, Atkinson. Melanoma Res. 2017 Jan 17.

The optimal duration of PD-1 antibodies for metastatic melanoma is unknown. In previous trials, there has been the potential to cease therapy if the patient achieves a complete response (CR). We aimed to assess the outcomes of patients who had ceased anti-PD-1 antibodies in this setting. A retrospective review was carried out of CR to PD-1-based therapy across two institutions. Patients were from the Pembrolizumab Named Patient Program (PEM NPP), Nivolumab monotherapy (NIVO), and reimbursed Pembrolizumab (r PEM). Patients had to have experienced a CR to PD-1-based therapy and ceased therapy because of this. Disease recurrence was the primary outcome measured. Twenty-nine patients (PEM NPP, N=20; Nivo, N=3; r PEM, N=6) ceased anti-PD-1 therapy after CR for observation. The median age was 64 (27-83) years. All patients had treatment discontinued for observation. The median time to CR was 10.5 months in the PEM NPP, 7.5 months on r PEM groups, and 17 months in the NIVO group. The median time off therapy in PEM NPP was 10 months, NIVO was 9 months, and r PEM was 4.5 months. To date, three patients have shown a relapse at a median follow-up off treatment of 8 months. This is the first report of patients who have intentionally ceased PD-1-based therapy because of CR. With a follow-up of 8 months off treatment, the risk of relapse was low. Data such as these are clinically relevant as we need to be able to discuss cessation of therapy and relevant from a pharmacoeconomic perspective, given the cost of PD-1 antibodies to society.

This study has not been looking at these ratties terribly long.  However, watchful studies of outcome and durability MUST continue.  There are also these perspectives from Melanoma Big Dogs:

A basic review by Weber and Agarwala:  Pick your poison by Weber and Agarwala, 9/2015

A review of data from 4/2016 with three additional links at the bottom of the post and this quote within ~      “In all patients, there is a plateauing, a so called tail on the curve, and it’s lasting many months to years, and about a third of patients have this long-term survival,” said Hodi. “Those who make it to 48 months, have a very good chance of surviving their disease.”
Nivolumab shows impressive OS in melanoma

And this from Dr. Daud, ASCO, 2016 (contains some really great graphs!!!):  Dr. Daud reviews ASCO 2016 - immunology updates for melanoma

And then there's me.  First dose of Nivolumab (Opdivo) in December 2010, last in June 2013 - still NED.  -  Glad ratties have long tails!!!!  love, c