Age Does Not Predict Outcomes For Elderly Patients With Myelodysplastic Syndromes Undergoing Hematopoietic Stem Cell Transplantation With Reduced-Intensity Conditioning
Authors: Abel Gregory A. , Kim Haesook T. , Armand Philippe , Cutler Corey S. , Antin Joseph H. , Koreth John , Ho Vincent T. , Soiffer Robert J. , Alyea Edwin P. 
Published: October 2019

Background
The National Care Determination for allogeneic hematopoietic stem cell transplantation (allo HSCT) for the treatment of myelodysplastic syndromes (MDS) stated that there is an absence of convincing evidence that allo HSCT improves health outcomes. A prospective data-gathering trial sponsored by the CIBMTR is ongoing; however, until such results are available, retrospective methods specifically comparing older populations are illustrative.

Methods
We analyzed outcomes for older patients with MDS undergoing HSCT with reduced intensity conditioning (RIC) at the Dana-Farber/BWH with uniform conditioning and graft versus host disease (GVHD) prophylaxis regimens from 2001 to 2011. Patients with CMML were excluded. Those aged 60-65, and those ≥ 66 were compared to assess overall survival (OS), progression free survival (PFS), and other HSCT-related outcomes. Aiming to build a better prognostic score using its significant components, we also assessed the association of the IPSS-R at transplantation as well as each of its components with OS, and fit multivariable Cox regression models with the new prognostic score as well as age.

Results
We identified 67 patients aged 60 or older who underwent RIC HSCT for MDS. All patients received fludarabine and intravenous busulfan as conditioning, and peripheral blood stem cells. GVHD prophylaxis included tacrolimus/rapamycin +/- MTX. The median age was 64 (60-74) years, and the majority (64%) had unrelated donors. 60% had advanced MDS (IPSS-R high risk or very high risk), 46% had poor risk cytogenetics, and 67% had high or very high disease risk index (DRI). The median age for the 60-65 group was 63; the median age for the ≥ 66 group was 69. We found no significant differences in PFS or OS by age category, as shown below (also see figure):
In addition, rates of 6-month grade III-IV GVHD (p=.45) and 2-year incidence of cGVHD (p=0.78) did not significantly differ. The IPSS-R performed only modestly in predicting 4-year OS for this older cohort (p=.20); however, a new 3-level score (including collapsed cytogenetic categories, dichotomous platelet count [ ≥ 50 or < 50], percent blasts in marrow and dichotomous ANC) performed better (p=.008; see figure). In two multivariable models, one that included the IPSS-R and another that included the new score, age was not a significant predictor of OS (p=.78 and .77 respectively).

Conclusions
Our data suggest that age alone should not limit availability of RIC HSCT for patients with MDS, as older patients in our elderly cohort faired similarly to younger ones with respect to important HSCT-related outcomes. Our new prognostic score, if validated, may be able to help risk-stratify patients. Finally, continued efforts are needed to reduce relapse in high-risk elderly MDS patients.

Disclosures:
No relevant conflicts of interest to declare.