The Intensity of the Induction Regimen Does Not Affect Post-Transplant Survival Among Patients with Newly Diagnosed Mantle Cell Lymphoma
Authors: Solh Melhem , Bashey Asad , Morris Lawrence E , Holland H. Kent , Zhang Xu , Solomon Scott R. 
Published: November 2021

Abstract
The routine use of autologous stem cell transplantation (ASCT) in first remission have significantly improved outcomes for patients with mantle cell lymphoma (MCL) (Hermann et al, jco 2009). The choice of the most appropriate induction regimen prior to transplant remains a controversial topic. Adding high dose cytarabine to RCHOP among young patients (&lt;65 years) results in superior PFS, higher toxicity but no improvement in overall survival when compared to RCHOP alone (Hermine O et al, Lancet 2016). The use of bendamustine/Rituxan (BR) compared to RCHOP in 2 randomized studies showed lower toxicity, higher PFS but similar overall survival. In this study, we investigated the effect of induction regimen intensity and the use of high dose cytarabine on post autologous stem cell transplant outcomes among MCL patients treated at our center.
59 patients who received ASCT for MCL between 2010 and 2020 were included in this analysis. Data were retrieved from our database where it was entered prospectively. Median age at diagnosis was 60 (45,76) years, stage IV (85%), B symptoms (32%), MIPI score (low 17%, intermediate 47%, high 28%) and ECOG performance 0-1 (81%). Induction regimen included BR (n=14), RCHOP (n=11), R-Hyper CVAD (n=14), RBAC(n=2) and RCHOP/RDHAP (n=18). 85% of patients were in CR and 15% in PR at time of transplant. All patients underwent chemo mobilization with a median time from diagnosis to transplant of 251 (119,1372) days. 30 patients (51%) received post-transplant rituximab maintenance. Patients were compared into 2 groups based on the use of high dose cytarabine in their induction regimen (table 1). Patients who received high dose cytarabine were younger and had a shorter time from diagnosis to transplant that patients who were treated without cytarabine. Survival endpoints for cytarabine based and no cytarabine based induction at 5 years post-transplant were as follows OS (82% vs 69%), DFS (65% vs 50%), Non-relapse mortality (4% vs 9%) and relapse (31% vs 41%) respectively ( figure 1). A multivariable cox analysis for OS, DFS, NRM and relapse showed that cytarabine had no effect on any of the endpoints. For OS, B symptoms and worse ECOG performance at Diagnosis (&gt;=2) were associated with worse OS. For relapse, higher MIPI score and no use of Rituxan maintenance resulted in higher relapse.
In conclusion, our data shows that among MCL patients receiving ASCT, the use of more intensive cytarabine based induction does not clearly improve long-term outcomes It is possible that use of ASCT compensates for the use of a less intense induction regimen. Disease (MIPI), Patient (ECOG)characteristics and use of post-transplant maintenance are factors that contribute to post transplant outcomes.
Figure 1 Figure 1.

Disclosures
Solh: Jazz Pharmaceuticals: Consultancy; Partner Therapeutics: Research Funding; BMS: Consultancy; ADCT Therapeutics: Consultancy, Research Funding.