Retrospective analysis of responses to second-line treatments of multiple myeloma after disease progression in patients who underwent ASCT.

person Hussein Awada Department of Translational Hematology and Oncology Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA, Cleveland, OH info_outline Hussein Awada, Adel Hajj Ali, Muhammad Faizan Ali, Shubham Adroja, Gauranga Mahalwar, Ashish Kumar, Arslan Babar, Faiz Anwer

Authors person Hussein Awada Department of Translational Hematology and Oncology Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA, Cleveland, OH info_outline Hussein Awada, Adel Hajj Ali, Muhammad Faizan Ali, Shubham Adroja, Gauranga Mahalwar, Ashish Kumar, Arslan Babar, Faiz Anwer Organizations Department of Translational Hematology and Oncology Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA, Cleveland, OH, Heart Vascular Thoracic Institute, Cleveland Clinic, Cleveland, OH, Akron General Medical Center, Akron, OH, Cleveland Clinic Akron General, Akron, OH, Cleveland Clinic Taussig Cancer Institute, Islamabad, Pakistan, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH Abstract Disclosures Research Funding No funding received Background: Most Multiple Myeloma (MM) patients who respond to initial treatment ultimately progress. Data regarding 2 nd line treatment remains scarce, but in general treatment relies on whether the disease is refractory to Lenalidomide (R) or not. Here, we report responses to 2 nd line treatments of MM patients in with disease progression (PD) following Autologous Stem Cell Transplant (ASCT). Methods: We retrospectively reviewed MM patients with PD after ASCT at Cleveland Clinic during the period of April 1, 2016 till December 31, 2021. Baseline demographic, clinical and cytogenetic features were obtained from electronic records. Patients who had PD after ASCT, as defined by IMWG criteria, were divided into two smaller subcohorts: R-refractory and R-sensitive. Outcomes were compared among treatment groups within each subcohort. Continuous variables are reported as means with standard deviations, while categorical variables are presented as percentages. Categorical variables were compared using the chi-squared test while the t test and ANOVA were used for continuous variables. Results: 127 patients who had PD following ASCT were identified (Table). Most common cytogenetic aberrancies were del(13) (RB) 34.6%, t(11;14) 18.9% and gain(1q) 15%. Pre-PD maintenance included R 58.3%, Bortezomib (V) 7.1%, RV combination 8.7% and other R-based regimens 9.4%, with no difference in time to disease progression (TTPD) between them (p = 0.82), and an average of 15.5 months TTPD among all patients. ISS III patients were likely to progress earlier than ISS II or I (10.91 vs 14.56 vs 20.33 months; p = 0.008), while high and standard-risk cytogenetics did not predict TTPD (12.62 vs 16.85 months; p = 0.092). Patient who achieved CR either pre or post-ASCT were less likely to progress compared to others with weaker responses (p = 0.032; p = 0.002). Patients who did not achieve CR post-ASCT progressed earlier than those with CR (12.37 vs 16.53 months; p = 0.041). In R-sensitive patients (n = 25), PD was not significantly different in patients on 2 nd line Daratumumab (D), R and dexamethasone (d) vs RVd (45.5% vs 60%; p = 0.505). In R-refractory patients (n = 57), PD was also not significantly different in DVd, Dd with Pomalidomide, or Carfilzomib (C)-based regimens (81.3% vs 68.2% vs 60%; p = 0.426). Time to 2 nd PD was significantly longer in DRd vs RVd (12.4 vs 3 months; p = 0.026) but similar in DVd vs DPd vs C-based regimens (6.75 vs 8 vs 5.89 months; p = 0.711). Conclusions: TTPD in MM post-ASCT is determined by the ISS stage and achieving CR but not by cytogenetic risk or maintenance choice. Current regimens used as 2 nd line in R-refractory patients are statistically indifferent, but DRd delays further PD compared to RVd in R-sensitive patients. Median Age 60 [38-77] Gender Males 56.7%; Females 43.3% Ethnicity White 85%; Black 11% ISS Stage I 33.90% II 33.10% III 18.90% Cytogenetic Risk Standard 33.90% High 44.10%