Auto-HCT versus allo-HCT in FL patients with ETF

For the treatment of follicular lymphoma (FL) patients experiencing early treatment failure (ETF) with an expected 5-year overall survival (OS) of approximately 50%, more efficient therapies are highly required after standard rituximab-based chemoimmunotherapy. Hematopoietic stem cell transplantation (HCT) can be a viable treatment option for relapsed FL patients, nevertheless its position has been questioned in terms of alternative options such as targeted agents and less toxic available therapies. Furthermore, there is an ongoing debate on how to interpret HCT-related findings due to the existence of substantial clinical heterogeneity in FL among trials. These studies usually analyze small numbers of patients with different disease states of relapsed and refractory FL in early and late relapse.

On 12 April 2018, Sonali M. Smith from the Section of Hematology/Oncology, University of Chicago, Chicago, IL, USA, and colleagues, published results in Cancer of their retrospective study investigating whether autologous or allogeneic HCT (auto-HCT, allo-HCT) is more efficient as the first transplantation option for high-risk FL patients with ETF.

In total, 440 FL patients with ETF who underwent auto-HCT or allo-HCT between 2002 and 2014 were enrolled in this retrospective analysis. Of them, 240 patients (median age = 56) received auto-HCT and 200 patients received allo-HCT (matched sibling donor [MSD; n = 105; median age = 52] or matched unrelated donor [MUD; n = 95; median age = 53]) as first transplantation. Study endpoints included OS, progression-free survival (PFS), relapse, and non-relapse mortality (NRM). Data were collected from the CIBMTR registry. The median follow-up was 73, 69, and 73 months for the auto-HCT, MSD HCT and MUD HCT, respectively.

Key findings

• Efficacy
  • 5-year OS in patients receiving auto-HCT, MSD or MUD HCT: 70% vs 73% vs 49%, P = 0.0008
  • 5-year adjusted probability of NRM in patients receiving auto-HCT, MSD or MUD HCT: 5% vs 17% vs 33%, P < 0.0001
  • 5-year PFS for the auto-HCT, MSD, or MUD cohorts: 38% vs 52% vs 43%, respectively, P = 0.10
  • 5-year adjusted probability of relapse/progression in patients receiving auto-HCT, MSD or MUD HCT: 58% vs 31% vs 23%, P < 0.0001
• GvHD
  • The cumulative incidences of grade 2–4 acute GvHD at Day 100 for the MSD and MUD cohorts: 35% and 35%, respectively, P = 0.94
  • The respective rates for Day 100 grade 3–4 acute GvHD: 13% and 16%, P = 0.62
  • 2-year probability of chronic GvHD for the MSD or MUD cohorts: 54% vs 58%; P = 0.54

In summary, these findings showed that HCT is an effective option for transplant-eligible FL patients with ETF. This analysis found that patients undergoing auto-HCT or MSD allo-HCT had a 70% survival rate. The authors stated that until there are no accurate risk-stratification tools for FL patients, auto-HCT and MSD allo-HCT should be the preferred therapy options as both of them offer excellent long-term survival rate for this high-risk patient population.