Venetoclax with decitabine vs intensive chemotherapy in acute myeloid leukemia: A propensity score matched analysis stratified by risk of treatment-related mortality

Hypomethylating agents (HMA) with venetoclax is a new standard for older/unfit patients with acute myeloid leukemia (AML). However, it is unknown how HMA with venetoclax compare to intensive chemotherapy (IC) in patients who are "fit" or "unfit" for IC. We compared outcomes of older patients with newly diagnosed AML receiving 10-day decitabine with venetoclax (DEC10-VEN) vs IC. DEC10-VEN consisted of daily venetoclax with decitabine 20 mg/m² for 10 days for induction and decitabine for 5 days as consolidation. The IC cohort received regimens containing cytarabine ≥1 g/m² /d. A validated treatment-related mortality score (TRMS) was used to classify patients at high-risk or low-risk for TRM with IC. Propensity scores were used to match patients to minimize bias. Median age of the DEC10-VEN cohort (n = 85) was 72 years (range 63-89) and 28% patients were at high-risk of TRM with IC. The comparator IC group (n = 85) matched closely in terms of baseline characteristics. DEC10-VEN was associated with significantly higher CR/CRi compared to IC (81% vs 52%, P < .001), and lower rate of relapse (34% vs 56%, P = .01), 30-day mortality (1% vs 24%, P < .01), and longer overall survival (OS; 12.4 vs 4.5 months, HR = 0.48, 95%CI 0.29-0.79, P < .01). In patients at both at high-risk and low-risk of TRM, DEC10-VEN showed significantly higher CR/CRi, lower 30-day mortality, and longer OS compared to IC. Patients at both high-risk and low-risk of TRM had comparable outcomes with DEC10-VEN. In conclusion, DEC10-VEN offers better outcomes compared to intensive chemotherapy in older patients with newly diagnosed AML, particularly in those at high-risk of TRM.

The LEukemia Artificial Intelligence Program (LEAP) in chronic myeloid leukemia in chronic phase: A model to improve patient outcomes

Extreme gradient boosting methods outperform conventional machine-learning models. Here, we have developed the LEukemia Artificial intelligence Program (LEAP) with the extreme gradient boosting decision tree method for the optimal treatment recommendation of tyrosine kinase inhibitors (TKIs) in patients with chronic myeloid leukemia in chronic phase (CML-CP). A cohort of CML-CP patients was randomly divided into training/validation (N = 504) and test cohorts (N = 126). The training/validation cohort was used for 3-fold cross validation to develop the LEAP CML-CP model using 101 variables at diagnosis. The test cohort was then applied to the LEAP CML-CP model and an optimum TKI treatment was suggested for each patient. The area under the curve in the test cohort was 0.81899.Backward multivariate analysis identified age at diagnosis, the degree of comorbidities, and TKI recommended therapy by the LEAP CML-CP model as independent prognostic factors for overall survival. The bootstrapping method internally validated the association of the LEAP CML-CP recommendation with overall survival as an independent prognostic for overall survival. Selecting treatment according to the LEAP CML-CP personalized recommendations, in this model, is associated with better survival probability compared to treatment with a LEAP CML-CP non-recommended therapy. This approach may pave a way of new era of personalized treatment recommendations for patients with cancer.

Outcomes with sequential FLT3-inhibitor-based therapies in patients with AML

BACKGROUND

Second-generation FLT3-inhibitors (FLT3i) demonstrated single-agent composite CR rates (CRc) of 45-55% in patients with relapsed/refractory (R/R) FLT3-mutated AML in phase II/III trials. However, > 85% of patients treated were prior FLT3i naïve. The response rates to sequential FLT3i exposure remain poorly defined.

METHODS

We retrospectively reviewed patients with FLT3-mutated AML between November 2006 and December 2019.

RESULTS

In frontline patients treated with a FLT3i (cohort 1), the CRc rates and median overall survival (OS) with the first (n = 56), second (n = 32), and third FLT3i-based (n = 8) therapy were 77%, 31%, and 25%, and 16.7 months, 6.0 months, and 1.4 months, respectively. In patients receiving a FLT3i-based therapy for the first time in a R/R AML setting (cohort 2), the CRc rates and median OS were 45%, 21%, and 10%, and 7.9 months, 4.0 months, and 4.1 months with the first (n = 183), second (n = 89), and third/fourth (n = 29) FLT3i-based therapy, respectively. In cohort 1, CRc rates with single-agent FLT3i (n = 21) versus FLT3i-based combinations (n = 19) in second/third sequential FLT3i exposures were 19% versus 42%, respectively. In cohort 2, the CRc rates with single-agent FLT3i (n = 82) versus FLT3i-based combinations (n = 101) in first FLT3i exposure were 34% versus 53%, respectively, and those with single-agent FLT3i (n = 63) versus FLT3i-based combinations (n = 55) in second/third/fourth sequential FLT3i exposures were 13% versus 25%, respectively.

CONCLUSION

CRc rates drop progressively with sequential exposure to FLT3i's in FLT3-mutated AML. In all settings, CRc rates were higher with FLT3i-based combinations compared with single-agent FLT3i therapy in similar FLT3i exposure settings.

10-day decitabine with venetoclax for newly diagnosed intensive chemotherapy ineligible, and relapsed or refractory acute myeloid leukaemia: a single-centre, phase 2 trial

BACKGROUND

Venetoclax combined with hypomethylating agents is a new standard of care for newly diagnosed patients with acute myeloid leukaemia (AML) who are 75 years or older, or unfit for intensive chemotherapy. Pharmacodynamic studies have suggested superiority of the longer 10-day regimen of decitabine that has shown promising results in patients with high-risk AML in phase 2 trials. We hypothesised that venetoclax with 10-day decitabine could have improved activity in patients with newly diagnosed AML and those with relapsed or refractory AML, particularly in high-risk subgroups.

METHODS

This single centre, phase 2 trial was done at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). The study enrolled older patients (aged >60 years) with newly diagnosed AML, not eligible for intensive chemotherapy; secondary AML (progressed after myelodysplastic syndrome or chronic myelomonocytic leukaemia); and relapsed or refractory AML. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 3 or less, white blood cell count less than 10 × 10⁹ per L, and adequate end-organ function. Patients with favourable-risk cytogenetics (eg, t[15;17] or core-binding factor AML) or who had received previous BCL2-inhibitor therapy were excluded. Patients received decitabine 20 mg/m² intravenously for 10 days with oral venetoclax 400 mg daily for induction, followed by decitabine for 5 days with daily venetoclax for consolidation. The primary endpoint was overall response rate. The secondary endpoints analysed within this report include safety, overall survival, and duration of response, in keeping with recommendations of European LeukemiaNet 2017 guidelines. All patients who received at least one dose of treatment were eligible for safety and response assessments. The trial was registered on ClinicalTrials.gov (NCT03404193) and continues to accrue patients.

FINDINGS

Between Jan 19, 2018, and Dec 16, 2019, we enrolled 168 patients; 70 (42%) had newly diagnosed AML, 15 (9%) had untreated secondary AML, 28 (17%) had treated secondary AML, and 55 (33%) had relapsed or refractory AML. The median age was 71 years (IQR 65-76) and 30% of patients had ECOG performance status of 2 or higher. The median follow-up for all patients was 16 months (95% CI 12-18; actual follow-up 6·5 months; IQR 3·4-12·4). The overall response rate was 74% (125 of 168 patients; 95% CI 67-80) and in disease subgroups were: 89% in newly diagnosed AML (62 of 70 patients; 79-94), 80% in untreated secondary AML (12 of 15 patients; 55-93), 61% in treated secondary AML (17 of 28 patients; 42-76), and 62% in relapsed or refractory AML (34 of 55 patients; 49-74). The most common treatment-emergent adverse events included infections with grades 3 or 4 neutropenia (n=79, 47%) and febrile neutropenia (n=49, 29%). 139 (83%) of 168 patients had serious adverse events, most frequently neutropenic fever (n=63, 38%), followed by pneumonia (n=17, 10%) and sepsis (n=16, 10%). The 30-day mortality for all patients was 3·6% (n=6, 95% CI 1·7-7·8). The median overall survival was 18·1 months (95% CI 10·0-not reached) in newly diagnosed AML, 7·8 months (2·9-10·7) in untreated secondary AML, 6·0 months (3·4-13·7) in treated secondary AML, and 7·8 months (5·4-13·3) relapsed or refractory AML. The median duration of response was not reached (95% CI 9·0-not reached) in newly diagnosed AML, 5·1 months (95% CI 0·9-not reached) in untreated secondary AML, not reached (95% CI 2·5-not reached) in previously treated secondary AML, and 16·8 months (95% CI 6·6-not reached) in relapsed or refractory AML.

INTERPRETATION

Venetoclax with 10-day decitabine has a manageable safety profile and showed high activity in newly diagnosed AML and molecularly defined subsets of relapsed or refractory AML. Future larger and randomised studies are needed to clarify activity in high-risk subsets.

FUNDING

US National Institutes of Health and National Cancer Institute.

High levels of immunoglobulin expression predict shorter overall survival in patients with acute myeloid leukemia

OBJECTIVES

It has been believed that immunoglobulins can only be produced by B lymphocytes and plasma cells. We have previously reported that IgG can be expressed in myeloblasts from patients with acute myeloid leukemia (AML) and plays a role in the proliferation and apoptosis of leukemic cells. However, its clinical impact has not been assessed.

METHODS

We assessed the expression of different classes of immunoglobulin in peripheral blood and bone marrow samples from 132 AML patients and correlated the levels of expression with clinicopathologic and molecular genetic features, as well as clinical outcome.

RESULTS

We found that, in addition to IgG, all classes of immunoglobulin are expressed in myeloblasts, including IgG, IgM, IgA, IgD, IgE, Igκ, and Igλ. The levels of IgG expression (coupled with Igκ or Igλ) are higher than those of IgM, IgA, IgD, and IgE. Using receiver operating characteristic (ROC) curve analysis, we identified two distinct groups of AML patients with differential expression of immunoglobulin and different clinical outcomes.

CONCLUSIONS

High levels of immunoglobulin expression are associated with monocytic differentiation, multilineage dysplasia, TET2 and KRAS mutations, and poor overall survival. Assessment of immunoglobulin may serve as a useful marker for prognostic stratification and target therapy.

Posttransplantation cyclophosphamide improves transplantation outcomes in patients with AML/MDS who are treated with checkpoint inhibitors

BACKGROUND

There have been concerns regarding increased peritransplantation complications, especially severe acute graft-versus-host disease (aGVHD), in patients with prior use of checkpoint inhibitors (CPI) before hematopoietic stem cell transplantation (HSCT).

METHODS

The authors performed a retrospective study of 43 patients with acute myeloid leukemia and/or myelodysplastic syndromes who were treated with an antiprogrammed cell death protein 1 (PD-1) (32 patients) or anticytotoxic T-lymphocyte-associated protein 4 (CTLA-4) (9 patients) blockade or both (2 patients) prior to HSCT with the primary outcome of aGVHD by day 100 after HSCT. Outcome analyses were stratified by GVHD prophylaxis as use of post-HSCT cyclophosphamide (PTCy) (22 patients) or not (non-PTCy) (21 patients).

RESULTS

The PTCy group demonstrated a trend toward lower grade 3 to 4 aGVHD when compared with the non-PTCy group (5% vs 22%), although the rates of grade 2 to 4 aGVHD were comparable (49% vs 56%). The interval between CPI and HSCT did not appear to impact the incidence of aGVHD. However, a higher incidence of grade 3 to 4 aGVHD was observed in patients who received >4 treatments of CPI prior to HSCT if they were not given PTCy as GVHD prophylaxis (43% vs 12%). Matched control analyses using patients with no prior use of CPI confirmed the increase in grade 3 to 4 aGVHD with those agents. However, that increased risk was limited to patients who did not receive PTCy and was not observed in patients who received PTCy as GVHD prophylaxis. Despite persistent improvement in GVHD with the use of PTCy, disease control was not compromised and progression-free survival at 1 year was found to be superior for patients treated with PTCy compared with those not receiving PTCy among patients with prior use of CPI (55% vs 22%).

CONCLUSIONS

The results of the current study indicated that HSCT with prior use of CPI appears feasible in patients with acute myeloid leukemia and/or myelodysplastic syndromes and the use of PTCy as GVHD prophylaxis improves outcomes.

Venetoclax and BCR-ABL Tyrosine Kinase Inhibitor Combinations: Outcome in Patients with Philadelphia Chromosome-Positive Advanced Myeloid Leukemias

BACKGROUND

Philadelphia chromosome-positive (Ph+) advanced leukemias, including acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) in myeloid blast phase (MBP), have poor outcomes. Venetoclax has shown synergism with BCR-ABL1 tyrosine kinase inhibitors (TKI) in preclinical studies. However, clinical activity of venetoclax and TKI-based regimens is unknown.

METHODS

We conducted a retrospective study on patients with Ph+ AML (n = 7) and CML-MBP (n = 9) who received venetoclax combined with TKI-based regimens at our institution.

RESULTS

Median patient age was 42 years, and the median number of prior therapy cycles was 5 (range 2-8). Nine patients received decitabine-based, and 7 received intensive chemotherapy-based regimens. Ten patients (63%) received ponatinib. The overall response rate (ORR) in 15 evaluable patients was 60% (1 complete remission [CR], 6 CR with incomplete hematologic recovery [CRi], 1 morphologic leukemia-free state, and 1 partial response). The ORR was 43% in Ph+ AML and 75% in CML-MBP. The median overall survival (OS) for all patients was 3.6 months, for AML OS was 2.0 months, and for CML-MBP OS was 10.9 months. The median relapse-free survival for AML and CML-MBP was 3.6 and 3.9 months, respectively. Compared to nonresponders, patients achieving CR/CRi had higher baseline Ph+ metaphases and BCR-ABL1 PCR.

CONCLUSIONS

Combination therapy of venetoclax with TKI-based regimens shows encouraging activity in very heavily pretreated, advanced Ph+ leukemias, particularly CML-MBP.

Long-term results of a phase 2 trial of nilotinib 400 mg twice daily in newly diagnosed patients with chronic-phase chronic myeloid leukemia

BACKGROUND

Nilotinib is a potent, second-generation inhibitor of BCR-ABL1 tyrosine kinase and has been approved as frontline and salvage therapy for patients with chronic-phase chronic myeloid leukemia (CP-CML).

METHODS

In this single-institution, phase 2 study, 122 patients with newly diagnosed CP-CML received nilotinib 400 mg twice daily. The median follow-up on study was 78.3 months (interquartile range, 58.4-96.5 months).

RESULTS

Fifty-six percent of patients remained on therapy at the last follow-up. Both the complete cytogenetic response rate and the major molecular response (MR) rate were 91%. Seventy-five percent and 59% of patients achieved a ≥4.5-log reduction in BCR-ABL1 transcripts (MR4.5) and a sustained MR4.5 beyond 2 years, respectively. The estimated event-free survival and overall survival rates at 5 years were 89% and 93%, respectively, and the corresponding rates at 10 years were 85% and 88%, respectively. Treatment discontinuation due to toxicity occurred in 19% of patients, mostly because of cardiovascular events (10%) and biochemical abnormalities (6%). The top 3 nonhematologic toxicities were rash (55%), elevated bilirubin (57%), and elevated aminotransferases (48%). Hematologic toxicity was transient and mild. Ischemic cardiovascular adverse events occurred in 8% of patients. Four patients (3%) progressed to accelerated or blast phase while on therapy, and 7 patients (6%) died on study.

CONCLUSIONS

The current data confirm the long-term efficacy of nilotinib 400 mg twice daily in patients with CP-CML. A majority of patients can achieve sustained MR4.5.

Long-term results of frontline dasatinib in chronic myeloid leukemia

BACKGROUND

Dasatinib is a second-generation tyrosine kinase inhibitor that, when used as frontline therapy, produces more and faster cytogenetic and molecular responses compared with imatinib. The authors report the long-term follow-up from the first study using dasatinib as initial therapy for chronic-phase chronic myeloid leukemia.

METHODS

Between November 2005 and August 2014, patients were randomly assigned to receive 100 mg daily or 50 mg twice daily. After June 2009, all patients started with 100 mg daily.

RESULTS

With a median follow-up of 6.5 years, 94 of 149 treated patients (63%) were still receiving dasatinib on study. The median patient age was 48 years (interquartile range, 37-55 years), and 9% of patients had a high risk Sokal risk score. The cumulative complete cytogenetic response rate at 11 years was 92.6%, the major molecular response (MR) rate was 88.2%, and the MR4.5 rate (indicating a ≥4.5-log reduction in BCR-ABL1 transcripts) was 79.5%. The median time to a major MR and MR4.5 was 6 and 23 months, respectively. A sustained MR4.5 (≥2 years) was achieved in 82 patients (55%). The 10-year overall survival, transformation-free survival, event-free survival, and failure-free survival rates were 89%, 95%, 86%, and 65%, respectively. Univariate analysis showed that the achievement of a complete MR was associated with improved overall survival. The most common reasons for treatment discontinuation were toxicity and elective discontinuation. The most common treatment-emergent grade 3 and 4 adverse events were fatigue, thrombocytopenia, and infections.

CONCLUSIONS

After this long-term follow-up, dasatinib continues to show an excellent safety profile and produces rapid cytogenetic responses and MRs, durable deep MRs, and excellent long-term survival outcomes in patients with chronic-phase chronic myeloid leukemia.

The face of remission induction

Acute myeloid leukaemia (AML) is a heterogeneous disease in which prognosis is determined by cytogenetic and molecular aberrations as well as patient-related factors, including age, prior haematologic disorders, and comorbidities. Despite the diverse disease biology, the standard of care for remission induction therapy has changed very little since its inception in 1973. Next generation sequencing has helped to increase our knowledge of the disease pathogenesis, allowing us to develop targeted and possibly more effective treatment options. Seven new agents have been approved for the treatment of AML since 2017, all of which are directed toward a specific molecular subtype or patient population. With the advent of these therapies, a more optimal, patient-specific approach rather than the historical 'one-size fits all' model can be utilised. This review will discuss the role of these novel therapies in the remission induction setting.

Treatment-free remission in chronic myeloid leukemia

Tyrosine kinase inhibitors (TKIs) represent a major breakthrough in the treatment of chronic myeloid leukemia (CML). Thanks to these agents, CML has been transformed from a disease with limited treatment options and a dismal prognosis into a more indolent disease with survival comparable to that of the general population. The need for ongoing TKI therapy remains controversial for several reasons, including cost and toxicity. Studies in CML patients with a sustained deep molecular response have demonstrated that stopping TKI therapy is feasible and safe. Given the heterogeneity of results reported in clinical trials, practice guidelines for optimal patient selection and proper monitoring after discontinuation of TKIs are proposed outside of clinical trials. Current data available show that 40% to 60% of patients who stop therapy relapse; molecular relapses typically occur within 6 months, but nearly all relapsing patients regain response upon reinitiation of the TKI. Several factors that predict for relapse have been investigated. Duration of prior TKI therapy, achievement of deep molecular response, depth of molecular response, prior interferon treatment, and Sokal risk score have been shown to be potential predictors for relapse. Leukemia stem cells that are resistant to TKIs, and that persist despite undetectable BCR/ABL1 transcript levels, likely are responsible for disease relapse after discontinuation. Efforts geared toward better identification of low levels of BCR/ABL1 transcript using new techniques such as digital polymerase chain reaction, along with eradicating CML clones using combination therapies with agents such as pegylated interferon or venetoclax with TKIs, will hopefully lead to a functional cure of this disease.

Economic modeling to evaluate the impact of chronic myeloid leukemia therapy management on the oncology care model in the US

Objective: To develop an economic model to evaluate changes in healthcare costs driven by restricting usage of branded tyrosine kinase inhibitors (TKIs) through substitution with generic imatinib among chronic myeloid leukemia (CML) patients in a typical Oncology Care Model (OCM) practice, and examine the impact on Performance-Based Payment (PBP) eligibility. Methods: An Excel-based economic model of an OCM practice with 1,000 cancer patients during a 6-month episode of care was developed. Cancer types and proportions of patients treated in the practice were estimated from an OCM report. All-cause healthcare costs were obtained from published literature. It was assumed that if a practice restricts usage of branded TKIs for newly-diagnosed CML patients, 80% of the market share of branded imatinib and 50% of the market shares of 2^nd-gen TKIs would shift to generic imatinib. Among established TKI-treated patients, it was assumed that 80% of the market share of branded imatinib and no patients treated with 2^nd-gen TKIs would shift to the generic. Results: Four CML patients were estimated for a 1,000-cancer patient OCM practice with a total baseline healthcare cost of $51,345,812 during a 6-month episode. If the practice restricts usage of branded TKIs, the shift from 2^nd-gen TKIs to generic imatinib would reduce costs by $12,970, while shifting from branded to generic imatinib lowers costs by $25,250 during a 6-month episode. Minimum reductions of $3,013,832 in a one-sided risk model and $2,372,010 in a two-sided risk model are required for PBP eligibility; the shift from 2^nd-gen TKIs to generic imatinib would account for 0.4% and 0.5% of the savings required for a PBP, respectively. Conclusions: This analysis indicates that the potential cost reduction associated with restricting branded TKI usage among CML patients in an OCM setting will represent only a small proportion of the cost reduction needed for PBP eligibility.

Targeted therapy paves the way for the cure of acute lymphoblastic leukaemia

The past decade has witnessed tremendous progress in the treatment of acute lymphoblastic leukaemia (ALL), primarily due to the development of targeted therapies, including tyrosine kinase inhibitors targeting BCR-ABL1 tyrosine kinase, monoclonal antibodies targeting cell surface antigens (CD19, CD20 and CD22), bispecific antibodies and chimeric antigen receptor T- cell therapy. A number of new therapies have been approved by the US Food and Drug Administration in the past 5 years, including blinatumomab in 2014, inotuzumab ozagamicin in 2017 and tisagenlecleucel in 2017 for relapsed/refractory ALL. This has led to tremendous improvement in long-term survival, of more than 50% in patients with precursor B-ALL [50-70% in patients with Philadelphia chromosome (Ph)-positive ALL)], 50-60% in T-ALL and 80% in mature B-ALL. Research is ongoing to optimize the benefit of targeted therapeutics with the goal of decreasing the use of cytotoxic therapies.

Transplantation in adults with relapsed/refractory acute lymphoblastic leukemia who are treated with blinatumomab from a phase 3 study

BACKGROUND

Blinatumomab, a bispecific T-cell-engaging (BiTE®) immuno-oncology therapy, demonstrated superior overall survival versus standard-of-care chemotherapy (SOC) in adults with relapsed/refractory B-cell precursor acute lymphoblastic leukemia (R/R ALL) in the phase 3 TOWER study. Herein, the authors reported clinical features and outcomes for those patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) after treatment with blinatumomab.

METHODS

In the TOWER study, adults with R/R ALL were randomized 2:1 to receive blinatumomab or SOC. Study treatment consisted of 2 cycles of induction with blinatumomab or SOC followed by consolidation and maintenance therapy. At any time after the first cycle, patients who were eligible for HSCT could proceed to HSCT.

RESULTS

Of the 97 patients who underwent HSCT during the study, baseline characteristics generally were comparable and donor types were similar between the patients treated with blinatumomab (65 patients) and those receiving SOC (32 patients). There was no evidence to suggest that the survival benefit of HSCT differed between the patients treated with blinatumomab and those receiving SOC (P = .68). On the basis of descriptive statistics, a survival benefit of HSCT versus no HSCT was not observed in patients who achieved complete remission with full, partial, or incomplete hematologic recovery with blinatumomab (odds ratio, 1.17; 95% CI, 0.54-2.53). The best outcomes were achieved in patients with no prior salvage therapy and with minimal residual disease response to blinatumomab regardless of on-study HSCT status.

CONCLUSIONS

Survival was found to be driven by response to study treatment and by salvage status regardless of on-study HSCT status. These data should be interpreted with caution because the current study was not designed to prospectively assess survival outcomes associated with HSCT after blinatumomab.

LAY SUMMARY

Evidence before this study: Blinatumomab is associated with superior morphologic and molecular response rates and superior overall outcome when compared with standard of care chemotherapy in adults with relapsed/refractory B-cell precursor acute lymphoblastic leukemia. Added value of this study: The best outcomes with blinatumomab were observed in patients who achieved minimal residual disease remission in first salvage treatment regardless of subsequent allogeneic stem cell transplantation (HSCT). Implications of all the available evidence: Patients achieving CR/CRh/CRi following blinatumomab can have a durable response with or without HSCT.

Idarubicin, cytarabine, and nivolumab in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome: a single-arm, phase 2 study

BACKGROUND

Outcomes for younger patients with acute myeloid leukaemia have moderately improved over the past two decades owing to better supportive care and recent introduction of novel targeted agents. Blocking PD-1 and its ligand's pathways enhances antileukaemia responses by enabling T cells in murine models. We aimed to assess the addition of nivolumab to frontline therapy with idarubicin and cytarabine in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome.

METHODS

This single-arm, phase 2 part of the phase 1-2 study of nivolumab in combination with idarubicin and cytarabine was done at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Eligible patients were aged 18-60 years (or >60 years if suitable for intensive chemotherapy), and had newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome, and an Eastern Cooperative Oncology Group performance status of 0-2. Induction included cytarabine 1·5 g/m² by 24-h continuous infusion daily on days 1-4 (3 days in patients >60 years) and idarubicin 12 mg/m² daily on days 1-3. Nivolumab 3 mg/kg was started on day 24 (range 22-26) and continued every 2 weeks for up to a year in responders. Responders received either up to five consolidation cycles of attenuated doses of idarubicin and cytarabine, or allogeneic stem cell transplantation if eligible. The primary endpoint was event-free survival. Efficacy and safety analyses were done in all patients who received at least one dose of study treatment. Secondary endpoints were relapse-free survival and overall survival. This ongoing trial is registered with ClinicalTrials.gov, number NCT02464657.

FINDINGS

Between Aug 7, 2015, and June 2, 2018, 44 patients were enrolled of whom 22 (50%) had adverse genetic risk by European Leukaemia Network classification. All patients were evaluable for safety and efficacy. At a median follow-up of 17·25 months (IQR 0·50-30·40), median event-free survival was not reached (95% CI 7·93-NR). Median relapse-free survival of responders was 18·54 months (95% CI 8·20-23·22). The median overall survival was 18·54 months (95% CI 10·81-28·81). Six patients had seven grade 3-4 immune-related adverse events with two cases of rash, two of colitis, and one each of transaminitis, pancreatitis, and cholecystitis. 19 (43%) of 44 patients achieved a response and proceeded to allogeneic stem cell transplantation, with grade 3-4 graft-versus-host disease observed in five (26%). No treatment related deaths were attributed to nivolumab.

INTERPRETATION

Addition of nivolumab to induction chemotherapy with idarubicin and cytarabine is feasible in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome. Post-transplant severe graft-versus-host disease could be improved, and earlier initiation of checkpoint inhibitor therapy is warranted in future studies.

FUNDING

The MD Anderson Cancer Center Support Grant CA016672, and the MD Anderson Cancer Center Leukaemia SPORE CA100632 from the National Cancer Institute, Bristol Myers Squibb.