Upfront Tandem Autologous Stem Cell Transplant Is Superior to Autologous or Allogeneic Stem Cell Transplant After Failure of a 1st Autologous Transplant,
Authors: Wong Adrian , LeMaistre Charles F. , Shaughnessy Paul , Bachier Carlos 
Published: October 2019

Abstract
Abstract 4094
Disease progression remains the main cause of treatment failure after autologous stem cell transplant (SCT) in patients with multiple myeloma (MM). It is unclear what is the best salvage therapy after failure of a 1st autologous SCT in MM.
We performed a retrospective study comparing 2nd autologous (auto-auto) versus 2nd allogeneic (auto-allo) SCT in patients progressing or relapsing after their 1st autologous SCT and compare their outcomes with patients receiving sequential planned double autologous (tandem) SCT as part of their upfront therapy for MM.
The data was collected from CIBMT reports and medical records at Texas Transplant Institute from 2001 to 2010. Patient's characteristics and outcomes are described in table 1. Response to 1st and 2nd SCT was determined at 100 days post transplant and classified as good (stringent complete remission [sCR], complete remission [CR], very good partial remission [VGPR]) or poor (partial remission [PR], stable disease [SD] or progressive disease [PD]). All patients in the auto-allo group received a reduced intensity regimen. 20% of the patients in the auto-auto group received maintenance therapy after their 1st transplant with either thalidomide or lenalidomide and 10% of the patients in the auto-allo group received maintenance therapy after their 1st transplant either with thalidomide. None of the patients in the tandem group received maintenance therapy. The overall survival was calculated from the date of the 2nd transplant to the known date of death in all groups. Patients in the auto-allo group (15.9 months) had a worse median survival than in the auto-auto group (39 months) with both of them having a worse survival compared to patients undergoing tandem transplants (64.3) (p value = 0.003) (FIGURE).Table:PATIENT CHARACTERISTICS AND OUTCOMESTandem (n=29)Auto-Auto (n=32)Auto-Allo (n=10)Median age, years (range)62 (41–78)62.5 (45–81)54 (43–63)Median days from diagnosis to 1st transplant224.5 (93–1344)226 (117–1074)254.5 (101–416)Median days from 1st to 2nd transplant149 (99–189)847 (210–4158)350 (88–1281)Median total CD34+ cell infused 1st transplant3.29 (2–12)5.87 (2–28)6.03 (2–14)2nd transplant3.22 (2–9)4.47 (2–19)5.25 (3–11)Median WBC engraftment11 (9–13)11 (9–47)N/AMedian Platelet engraftment16 (10–19)15 (10–23)N/ACytogenetics High Risk17%3%10%ISS at 1st transplant I31%41%40%II34%12%0III14%6%10%ISS at 2nd transplant I48%53%40%II17%9%0III10%13%10%Response to 1st transplant Good10%63%70%Poor80%25%20%Response to 2nd transplant Good52%47%30%Poor41%41%70%Median Followup (months)57.1 (3.4–76.7)24.6 (10.5–87.8)48.0 (31.9–64.0)Maintenance Therapy after 1st transplant028%10%Figure:OVERALL SURVIVALFigure:. OVERALL SURVIVAL
Forward stepwise Cox regression analysis was used to measure factors affecting overall survival. Factors used for analysis included age, cytogenetics (high risk = mutated p53, t(14;16), t(4;14), del 13), International Staging System (ISS) before 1st and 2nd SCT, use of maintenance therapy after 1st SCT, days from diagnosis to 1st SCT and days from 1st to 2nd SCT, CD34+ cells infused at 1st and 2nd SCT. Age and ISS of III at 2nd transplant were identified as factors affecting survival in the auto-auto group (hazard ration of 1.081 and 5.700, respectively).
In conclusion, overall survival after salvage from 2nd autologous stem cell transplant is longer than after a 2nd allogeneic transplant. Upfront, planned tandem autologous stem cell transplant is superior to both salvage strategies. Larger, randomized trials are needed to confirm these results.

Disclosures:
Shaughnessy: Otsuka: Honoraria, Speakers Bureau; Millenium: Honoraria, Speakers Bureau; Genzyme: Honoraria, Speakers Bureau.