‘Very encouraging’ primary CNS lymphoma response to HCT-ASCT

Treatment-naive primary central nervous system lymphoma shows high rate of complete response to high-dose chemotherapy plus autologous stem cell transplantation approach

medwireNews: Treatment with high-dose chemotherapy plus autologous stem cell transplantation (HCT-ASCT) is an effective approach to consolidate remission in patients with a new diagnosis of primary central nervous system (CNS) lymphoma, suggest phase II trial findings.

A total of 79 patients with a median age of 56 years received a sequential induction regimen comprising five cycles of rituximab plus four cycles of high-dose methotrexate (ie, 8000 mg/m2) followed by two cycles of rituximab , cytarabine and thiotepa . After a 3-week break, they received the consolidation regimen of rituximab, carmustine, thiotepa and autologous stem cells. Only participants who did not achieve a complete response after HCT-ASCT subsequently received whole-brain radiotherapy.

The primary endpoint of complete response by day 30 after HCT-ASCT was achieved by 77.2% of study participants, while a further 13.9% achieved a partial response, as reported in The Lancet Haematology.

After a median follow-up of 57.4 months, progression free-survival was a median of 74.0 months, with 78.5% and 64.8% of patients remaining progression-free at 1 and 5 years, respectively. The overall survival results were similarly “encouraging”, say the researchers, with the median not reached and 1- year and 5-year survival rates of 92.0% and 79.0%, respectively.

They caution, however, that they did not “systematically collect information about salvage treatments given outside of the study, which could have provided valuable information to understand the survival observed in this study.”

Researcher Gerald Illerhaus, from Klinikum Stuttgart in Germany, and colleagues also acknowledge that “the good long-term survival observed could be partly attributable to selection bias”.

In a linked commentary, Stefan Hohaus (Università Cattolica del Sacro Cuore, Rome, Italy) describes the results as “very encouraging” and believes that the trial is a “clear step towards more efficient therapies for primary CNS lymphoma than those at present”.

But he adds: “We still have to await the results of the randomised MATRix trial to better assess the place of autologous stem cell transplantation in first-line therapy of primary CNS lymphoma.”

During the induction phase, the most common grade 3 or worse haematological adverse events were thrombocytopenia, leukopenia and anaemia, while infections and elevated transaminases were the main nonhaematological toxicities.

Nearly all patients experienced leukopenia and thrombocytopenia of grade 3 or higher during HCT-ASCT. Illerhaus et al say that haematological toxicities were expected, but that fever, infections and mucositis were additional severe adverse effects.

They attribute four deaths to study treatment, of which three deaths occurred during induction and one 4 weeks after HCT-ASCT.

References

Illerhaus G, Kasenda B, Ihorst G, et al. High-dose chemotherapy with autologous haemopoietic stem cell transplantation for newly diagnosed primary CNS lymphoma: a prospective, single-arm, phase 2 trial. Lancet Haematol 2016; Advance online publication 12 July. DOI: http://dx.doi.org/10.1016/S2352-3026(16)30050-3

Hohaus S. High-dose therapy for primary CNS lymphoma. Lancet Haematol 2016; Advance online publication 12 July. DOI: http://dx.doi.org/10.1016/S2352-3026(16)30060-6

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