Session: 731. Clinical Autologous Transplantation: Results: Poster III
Hematology Disease Topics & Pathways:
multiple myeloma, Biological, Diseases, Therapies, Technology and Procedures, Plasma Cell Disorders, cytogenetics, Lymphoid Malignancies, transplantation
METHODS: Pts were classified as high risk (HR) if either conventional cytogenetics or FISH demonstrated at least one of the following 1q+, 1p-, 17p-, 13q-, t(4;14), or t(14;16), realizing that the inclusion of 13q- by FISH alone and 1p- in the HR MM definition is controversial. Pts with normal chromosomes or those with trisomies and hyperdiploidy were considered standard-risk (SR). We compared progression-free survival (PFS) and overall survival (OS) via a retrospective analysis of pts at the University of Miami Sylvester Comprehensive Cancer Center who underwent auto-HCT between January 2014 and December 2017 for MM. Survival analyses were performed using the log-rank test, with significance at p-value < 0.05.
RESULTS: Male pts comprised 56% of the population, and 40% of pts were of Hispanic ethnicity. Of 205 pts undergoing auto-HCT, 108 (53%) had at least one HR cytogenetic abnormality. Interestingly, the depth of response to pre-transplant induction was higher in pts classified as HR, with 71% (77 of 108) achieving at least a very good partial response (VGPR), while 24% (23 of 96) SR pts achieved VGPR. While OS remained largely unaffected in HR pts (34.0 m vs. 35.1 m, p = 0.27); HR pts had an inferior PFS compared to SR pts (21.9 m vs. 25.7 m, p = 0.041). The presence of trisomies did not negate the poorer PFS of HR pts.
When we evaluated specific HR CG abnormalities, OS and PFS in patients with 1q+ or t(4;14) were surprisingly comparable to SR pts, indicating a significant benefit from auto-HCT. On the other hand, OS was significantly decreased in pts with 1p- when compared to standard risk (16.5 m vs. 35.1 m, p = 0.004) or other high-risk patients (16.5 m vs. 35.4 m, p = 0.01), implying that 1p- group derive no benefit from auto-HCT. Similarly, OS was shorter in pts with t(14;16) (16.5 m vs. 34.4 m, p = 0.025) and with 17p- (26.6 m vs. 35.1 m, p=0.01), however the PFS was not affected in these populations. In pts with 13q-, PFS was significantly shorter (20.3 m vs. 25.7 m, p=0.023) compared to SR pts without affecting OS.
CONCLUSION: At our center in a retrospective analysis of 205 pts: a) patients with HR MM responded better and faster than SR pts to induction, b) those with 1p- did not derive any benefit from transplant and c) pts with 17p- and t(14;16) had some short term benefit (similar PFS to SR group) but at the end their OS remained inferior. Nevertheless, we consider a very important finding the fact that, by having auto-HCT, pts with 1q+ and t(4;14), equalized their PFS and OS to those of SR pts. Based on these findings, patients with 1q+ and t(4;14) should still have a transplant in CR1 even after optimal induction. Whether 17p- and t(14;16) pts can extend PFS benefit after transplant into OS benefit with maintenance regimens stronger than lenalidomide alone remains to be determined.
Disclosures: Hoffman: Celgene: Honoraria, Speakers Bureau; Loxo: Current equity holder in publicly-traded company; Seattle Genetics: Research Funding.
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