Maintenance lenalidomide in newly diagnosed transplant eligible and non-eligible myeloma patients; profiling second primary malignancies in 4358 patients treated in the Myeloma XI Trial

Background

Early trials of long-term lenalidomide use reported an increased incidence of second primary malignancy (SPM), including acute myeloid leukaemia and myelodysplastic syndrome. Later, meta-analysis suggested the link to be secondary to lenalidomide in combination with melphalan.

Methods

Myeloma XI is a large, phase III randomised trial in-which lenalidomide was used at induction and maintenance, in transplant eligible (TE) and non-eligible (TNE) newly diagnosed patients (NCT01554852). Here we present an analysis of SPM incidence and profile the SPM type to determine the impact of autologous stem cell transplantation (ASCT) and lenalidomide exposure in 4358 patients treated on study. Data collection took place from the start of the trial in May 2010, to May 2019, as per the protocol timeline. The Median follow-up following maintenance randomisation was 54.5 and 46.1 months for TE and TNE patients, respectively.

Findings

In the TE pathway, the overall SPM incidence was 7.7% in lenalidomide maintenance patients compared to 3.2% in those being observed (p = 0.006). Although the TNE lenalidomide maintenance patients had the greatest SPM incidence (15.4%), this was not statistically significant when compared to the observed patients (10%, p = 0.10).The SPM incidence was higher in patients who received lenalidomide at induction and maintenance (double exposure), when compared to those treated with lenalidomide at one time point (single exposure). Again, this was most marked in TNE patients where the overall SPM incidence was 16.9% in double exposed patients, compared to 11.7% in single exposed patients, and 11.2% in patients who did not receive lenalidomide (p = 0.04). This is likely an effect of treatment duration, with the median number of cycles being 27 in the TNE double exposed patients, vs 6 in the single exposure patients.Haematological SPMs were uncommon, diagnosed in 50 patients (incidence 1.1%). The majority of cases were diagnosed in TE patients treated with lenalidomide maintenance (n = 25, incidence 2.8%), suggesting a possible link with melphalan. Non-melanoma skin cancer incidence was highest in patients receiving lenalidomide maintenance, particularly in TNE patients, where squamous cell carcinoma and basal cell carcinoma were diagnosed in 5.5% and 2.6% of patients, respectively. The incidence of most solid tumour types was higher in lenalidomide maintenance patients.Mortality due to progressive myeloma was reduced in patients receiving lenalidomide maintenance, noted to be 16.6% compared 22.6% in those observed in TE patients and 32.7% compared to 41.5% in TNE patients. SPM related mortality was low, 1.8% and 6.1% in TE and TNE lenalidomide maintenance patients, respectively, compared to 0.4% and 2.8% in those being observed.

Interpretation

This provides reassurance that long-term lenalidomide treatment is safe and associated with improved outcomes in TE and TNE populations, although monitoring for SPM development should be incorporated into clinic review processes.

Funding

Primary financial support was from Cancer Research UK [C1298/A10410].

A Pilot Study of Lenalidomide Maintenance Therapy after Autologous Transplantation in Relapsed or Refractory Classical Hodgkin Lymphoma

For patients with relapsed or refractory classical Hodgkin lymphoma (cHL), salvage chemotherapy followed by consolidation with autologous stem cell transplant (ASCT) remains the standard of care. Even with this aggressive treatment strategy, 5-year progression-free survival is ≤50%, and there remains interest in maintenance strategies to improve long-term disease-free survival. Lenalidomide is an immunomodulatory agent with demonstrated activity in multiple subtypes of lymphoma including cHL, and has also been shown to improve both progression-free and overall survival as maintenance therapy after ASCT in multiple myeloma. This multicenter study evaluated maintenance lenalidomide after ASCT for patients with cHL. Patients were enrolled 60 to 90 days post-transplant and received oral lenalidomide on days 1 to 28 of 28-day cycles for a maximum of 18 cycles. Lenalidomide was started at 15 mg daily and increased to maximum of 25 mg daily if tolerated. The primary objective of this study was to assess the feasibility of this regimen, with a goal <30% rate of discontinuation at or before cycle 12 for drug-related reasons. Twenty-seven patients were enrolled and 26 received at least 1 dose of lenalidomide. With a median follow-up of 51.3 months (range, 12.2 to 76.2 months), 23 of 26 patients were alive. Median event-free survival was 9.4 months and median progression-free survival had not been reached, with 17 of 26 patients (65.4%) remaining in remission at last follow-up. Excluding 4 patients who discontinued therapy for progression and 2 who discontinued due to noncompliance, the discontinuation rate at or before cycle 12 was 52%. Treatment was complicated by a high frequency of hematologic adverse events, with 15 patients (58%) experiencing grade 3 to 4 hematologic toxicity and 5 (19%) experiencing grade 4 hematologic toxicity. We conclude that the regimen of maintenance lenalidomide explored in this study is not feasible for patients with cHL immediately following ASCT. An alternative lenalidomide dose or schedule may be better tolerated following ASCT for patients with relapsed or refractory cHL.

[Involvement of innate immunity in the expansion of multiple myeloma cells and therapeutic intervention with lenalidomide]

Multiple myeloma (MM) cells acquire dormancy and drug resistance via their interaction with bone marrow stroma cells (BMSCs) in a hypoxic microenvironment. In this study, we found a positive expression of CD180/MD-1 complex (a non-canonical toll-like receptor) on MM cells, which was markedly up-regulated under adherent and/or hypoxic conditions. Bacterial lipopolysaccharide (LPS) enhanced the growth of MM cells via the activation of MAP kinases, an effect which showed a positive correlation with the expression levels of CD180. LPS administration significantly increased CD180/CD138 double-positive cell number in a murine xenograft model after the inoculation of MM cells directly attached to BMSCs. Notably, the shRNA-mediated knockdown of CD180 terminated the LPS response in vitro and in vivo. Promoter analyses identified IKZF1 (Ikaros) as a pivotal transcriptional activator of the CD180 gene, whose transcription was activated via cell adhesion and hypoxia by increasing Ikaros expression and its binding to the promoter region. Pharmacological targeting of Ikaros with lenalidomide ameliorated the response of MM cells to LPS in a CD180-dependent manner in vitro and in vivo. CD180/MD-1 pathway may represent a novel mechanism for the regulation of the growth of MM cells in BM milieu and may serve as a therapeutic target to prevent the regrowth of dormant MM cells.