Long-term tolerability and efficacy after initial PegIFN-alpha addition to dasatinib in CML-CP : Five-year follow-up of the NordCML007 study

Objectives Treatment-free remission (TFR) has emerged as a treatment goal in chronic myeloid leukemia in the chronic phase (CML-CP). Attempts to increase proportion of patients achieving TFR include combination of tyrosine kinase inhibitors (TKI) and other drugs. Interferon-alpha in addition to TKI has shown promising efficacy but with dose-dependent toxicity and discontinuations. NordCML007 was initiated to study the efficacy and safety of low dose pegylated IFN-alpha (PegIFN-alpha) in combination with dasatinib (DAS) in CML-CP. Methods Forty patients with newly diagnosed CML-CP were given DAS upfront. After month 3 (M3) 15 mu g/wk of PegIFN-alpha was added and increased to 25 mu g/wk from M7 until M15. DAS treatment was continued and adverse events and BCR-ABL1 qRT-PCR values were reported yearly after M24. Results from M1 to M18 have previously been published, and here we present long-term data. Results After 5 years of follow-up, there were no suspected unexpected serious adverse reactions, no increase in serosal effusions, no disease progressions and no CML-related deaths. Rates of MR3.0 (MMR), MR4.0 and MR4.5 were 84.6%, 64.1% and 51.3% respectively at M60, and 95% of patients reached MMR at some point during the study. Conclusion Initial addition of PegIFN-alpha to DAS shows good long-term efficacy without increased toxicity.Peer reviewe

IFN-α with dasatinib broadens the immune repertoire in patients with chronic-phase chronic myeloid leukemia

In chronic myeloid leukemia (CML), combination therapies with tyrosine kinase inhibitors (TKIs) aim to improve the achievement of deep molecular remission that would allow therapy discontinuation. IFN-alpha is one promising candidate, as it has long-lasting effects on both malignant and immune cells. In connection with a multicenter clinical trial combining dasatinib with IFN-alpha in 40 patients with chronic-phase CML (NordCML007, NCT01725204), we performed immune monitoring with single-cell RNA and T cell receptor (TCR) sequencing (n = 4, 12 samples), bulk TCR beta sequencing (n = 13, 26 samples), flow cytometry (n = 40, 106 samples), cytokine analyses (n = 17, 80 samples), and ex vivo functional studies (n = 39, 80 samples). Dasatinib drove the immune repertoire toward terminally differentiated NK and CD8+ T cells with dampened functional capabilities. Patients with dasatinib-associated pleural effusions had increased numbers of CD8(+) recently activated effector memory T (Temra) cells. In vitro, dasatinib prevented CD3-induced cell death by blocking TCR signaling. The addition of IFN-alpha reversed the terminally differentiated phenotypes and increased the number of costimulatory intercellular interactions and the number of unique putative epitope-specific TCR clusters. In vitro IFN-alpha had costimulatory effects on TCR signaling. Our work supports the combination of IFN-alpha with TKI therapy, as IFN-alpha broadens the immune repertoire and restores immunological function.Peer reviewe

Treatment-free remission after a second TKI discontinuation attempt in patients with Chronic Myeloid Leukemia re-treated with dasatinib – interim results from the DAstop2 trial

Tyrosine kinase inhibitor (TKI) discontinuation in chronic myeloid leukemia (CML) has become part of routine care for patients with a sustained deep molecular response (DMR). Approximately 50% experience a molecular relapse upon TKI cessation. Most of them quickly regain DMR upon TKI resumption. Whether these patients can achieve a second treatment-free remission (TFR) remains unclear. DAstop2 (ClinicalTrials.gov ID: NCT03573596) is a prospective study including patients with a failed first TFR attempt re-treated with any TKI for ≥ one year. Upon entering the study, patients received the TKI dasatinib for additional two years. Patients with sustained DMR for ≥1 year qualified for a second TKI stop. Ninety-four patients were included between Oct 2017-Dec 2021. At the time of data analysis, 62 patients had attempted a 2nd stop. After a median follow-up of 27 months from 2nd stop, TFR rates were 61, 56 and 46% at 6, 12 and 24 months respectively. No progression to advanced stage disease was seen and 87% had re-achieved MR4 within a median of 3 months from TKI re-initiation. In summary, we show that a 2nd TFR attempt after dasatinib treatment is safe, feasible and TFR rates seem in the range of those reported in trials of a first TKI stop.Peer reviewe