Profile of Long-Term Survivors in Multiple Myeloma

Background: The treatment revolution of multiple myeloma (MM) with the advent of novel therapies, proteasome inhibitors, immunomodulators and newer drugs lead to increased survival. Clinical characteristics at diagnosis of Long-term survivor (>5 years after the start of treatment) were described; however data regarding the profile of lines of treatment is very limited. The aim of this study was to describe the profiles of response of this population.

Methods: The Poitou‐Charentes cancer registry has exhaustively registered incident cases of MM from 2008 to 2010. The follow-up date was December 31st, 2018. Patients (pts) alive after 5 years from the start of first line treatment were considered long-term survivors and their data were collected from their medical files. Three pts profiles were studied, very long responder (VLR) treated with a single line; long responder (LR) treated with [2-3] lines; and advanced (AdMM) [4 lines +[. Smoldering Myeloma, AL amyloidosis, lost to follow-up pts were excluded from the analysis.

Results: Among the 396 MM registered, 177 were alive after 5 years, and 158 were included in the study. The mean age was 62.3 +/-11, sex ratio 1.2, 51% IgG, 25% IgA and 20% Light Chain isotype. ISS1 was 42%, 34% ISS2 and 14% ISS3. The median follow-up after the 5-year landmark was 39.9 +/-13 months and 52% pts died during follow-up. Overall, the median number of lines was 2.9 +/-2, 44% had at least one ASCT, 83% received Bortezomib, 72% Lenalidomide, 48% Thalidomide, 22% Pomalidomide, 20% Daratumumab (usually 3 lines+). VLR represented 19%, 27% LR, and 54% AdMM. In VLR group, 43% received a Bortezomib-based regimen (2 or 3 drugs) followed by ASCT, 47% a Melphalan-based regimen plus Thalidomide (MPT) or Bortezomib (MPV). In LR group, first line comprised: 39% Bortezomib-based regimen and ASCT versus 24% MPT and 15% MPV. Second line for LR group: 75% had Lenalidomide single agent or combination, 22% had a Bortezomib-based regimen, 17% had an ASCT. In the LR group, 45% received a third line: 40% Lenalidomide, mostly single agent, 25% a Bortezomib-based regimen and 3% had an ASCT. The AdMM group had a mean of 5.9 +/-1.6 lines (range 4 -11) and 56% of RR patients had at least one ASCT.

Conclusion: Approximately 40% of MM were long-term survivors at 5 years from start of therapy in 2010, mainly on the basis of proteasome inhibitors and immunomodulators-based regimens plus use of ASCT. The vast majority of pts reached the 5 years cut-off with [4;+[ lines, and very few pts were real long-term survivors with an early prolonged control of Myeloma. Future perspective will look into 10 years long-term survival, including novel drug developments with the advent of immunotherapy.