Allo-Transplant Tied to Better PFS in Advanced Cutaneous T-Cell Lymphomas

Allogeneic hematopoietic stem cell transplantation (HSCT) was associated with significant improvements in progression-free survival (PFS) in patients with advanced cutaneous T-cell lymphomas (CTCLs), according to the propensity score-matched controlled CUTALLO study from France.

In an intention-to-treat (ITT) population of 99 patients, median progression-free survival was 9 months in the HSCT group compared with 3 months in the non-HSCT group (HR 0.38, 95% CI 0.21-0.69, P<0.0001), reported Adèle de Masson, MD, of Saint-Louis Hospital, Assistance Publique-Hopitaux de Paris, and colleagues.

The 1-year cumulative incidence of relapse in the HSCT group was 45.4% versus 86.0% in the non-HSCT group (cause-specific HR 0.29, 95% CI 0.17-0.58), while the 1-year cumulative incidence of non-relapse mortality was 8.5% compared with 0%, respectively (P=0.017), they noted in The Lancet.

The 1-year PFS rate in the matched HSCT group was 50.5% compared with 14.3% in the matched non-HSCT group (HR 0.33, 95% CI 0.17-0.61).

CTCLs, including mycosis fungoides and Sézary syndrome, are rare malignancies of skin-homing T cells. Advanced-stage CTCLs are associated with a median overall survival of less than 5 years. They also substantially affect quality of life, inducing visible skin changes such as erythroderma, as well as tumors, pruritus, infections, pain, and asthenia.

Few treatments have been shown to improve PFS in prospective controlled studies, and none have been shown to increase overall survival, noted de Masson and colleagues.

However, case series have suggested that allogeneic HSCT "potentially induces a graft-versus-lymphoma effect leading to long-lasting CTCLs remission in some people," they added.

In the ITT population, 30 participants died -- 22% of the HSCT group and 41% of the non-HSCT group. There was a non-significant benefit in median overall survival observed for the HSCT group (not reached vs 26.9 months, respectively).

In a commentary accompanying the study, Madiha Iqbal, MBBS, MD, and Mohamed Kharfan-Dabaja, MD, both of the Mayo Clinic Cancer Center in Jacksonville, Florida, noted that "despite the small number of patients, the significantly better progression-free survival is noteworthy and will probably encourage a practice change to offer allogeneic HSCT to patients with CTCL earlier in the disease course."

The study also lays the foundation for "future prospective studies evaluating novel conditioning regimens and incorporating maintenance and consolidative strategies to mitigate relapse risk," they wrote.

In the per-protocol population, 78% of patients in the HSCT group had 101 serious adverse events (AEs), while 67% in the non-HSCT group had 70 serious AEs. In the HSCT group, the 3-month cumulative incidence of acute graft-versus-host disease (GVHD) was 55.9%, and was 31.4% for chronic GVHD. The most common serious AE other than GVHD in both groups was infection, occurring in 59% of patients in the HSCT group and 44% in the non-HSCT group.

There was a mean improvement in EORTC Quality of Life Questionnaire C30 scores over time in the HSCT group. "This is an important finding, since HSCT recipients in complete remission might have chronic GVHD, which can considerably impair their quality of life," de Masson and colleagues observed.

The prospective CUTALLO study was conducted at 30 hospitals across France. Patients with an available sibling or HLA-matched unrelated donor received reduced-intensity conditioning allogeneic HSCT. Treatment for patients in the non-HSCT group was not standardized and was left to the choice of investigator, and was dependent on CTCL subtype, stage, presence of large-cell transformation, and previous treatments.

Study participants had advanced-stage mycosis fungoides or Sézary syndrome, and at least one poor prognostic criteria. Patients were excluded if they were not in complete or partial remission of disease. Median age at the time of diagnosis was 46.1 years in the HSCT group and 53.6 years in the non-HSCT group, and 64% of patients were men in each group.

Among the 55 patients in the HSCT group, 51 could be individually matched on their propensity score to one patient from the non-HSCT group.

de Masson and colleagues acknowledged the study had several limitations, including the small number of patients and heterogeneity in the study groups. However, in their commentary, Iqbal and Kharfan-Dabaja noted that biological assignment trials "can overcome the feasibility of patient accrual in a rare study population."

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