Phase I Study of Alvocidib Followed by 7+3 (Cytarabine + Daunorubicin) in Newly Diagnosed Acute Myeloid Leukemia

PURPOSE

Alvocidib is a cyclin-dependent kinase 9 inhibitor leading to downregulation of the antiapoptotic BCL-2 family member, MCL-1. Alvocidib has shown clinical activity in a timed sequential regimen with cytarabine and mitoxantrone in relapsed/refractory and newly diagnosed acute myeloid leukemia (AML) but has not been studied in combination with traditional 7+3 induction therapy.

PATIENTS AND METHODS

A multiinstitutional phase I dose-escalation study of alvocidib on days 1-3 followed by 7+3 (cytarabine 100 mg/m²/day i.v. infusion days 5-12 and daunorubicin 60 mg/m² i.v. days 5-7) was performed in newly diagnosed AML ≤65 years. Core-binding factor AML was excluded.

RESULTS

There was no MTD on this study; the recommended phase II dose of alvocidib was 30 mg/m² i.v. over 30 minutes followed by 60 mg/m² i.v. infusion over 4 hours. There was one dose-limiting toxicity of cytokine release syndrome. The most common grade ≥3 nonhematologic toxicities were diarrhea (44%) and tumor lysis syndrome (34%). Overall, 69% (22/32) of patients achieved complete remission (CR). In an exploratory cohort, eight of nine (89%) patients in complete remission had no measurable residual disease, as determined by a centralized flow cytometric assay. Clinical activity was seen in patients with secondary AML, AML with myelodysplastic syndrome-related changes, and a genomic signature of secondary AML (50%, 50%, and 92% CR rates, respectively).

CONCLUSIONS

Alvocidib can be safely administered prior to 7+3 induction with encouraging clinical activity. These findings warrant further investigation of alvocidib combinations in newly diagnosed AML. This study was registered at clinicaltrials.gov identifier NCT03298984.

Differentiating the Differentiation Syndrome Associated with IDH Inhibitors in AML

Isocitrate dehydrogenase (IDH) inhibitors have clinical activity in acute myeloid leukemia, in part, by differentiating blasts to mature myeloid cells. In the largest systematic analysis to date, differentiation syndrome was seen in 19% of patients treated with IDH inhibitors. Early recognition with uniform diagnostic criteria, as utilized in acute promyelocytic leukemia, may reduce subsequent complications.See related article by Norsworthy et al., p. 4280.

Special considerations in the management of adult patients with acute leukaemias and myeloid neoplasms in the COVID-19 era: recommendations from a panel of international experts

The ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 is a global public health crisis. Multiple observations indicate poorer post-infection outcomes for patients with cancer than for the general population. Herein, we highlight the challenges in caring for patients with acute leukaemias and myeloid neoplasms amid the COVID-19 pandemic. We summarise key changes related to service allocation, clinical and supportive care, clinical trial participation, and ethical considerations regarding the use of lifesaving measures for these patients. We recognise that these recommendations might be more applicable to high-income countries and might not be generalisable because of regional differences in health-care infrastructure, individual circumstances, and a complex and highly fluid health-care environment. Despite these limitations, we aim to provide a general framework for the care of patients with acute leukaemias and myeloid neoplasms during the COVID-19 pandemic on the basis of recommendations from international experts.

Phase II study of pevonedistat (P) + azacitidine (A) versus A in patients (pts) with higher-risk myelodysplastic syndromes (MDS)/chronic myelomonocytic leukemia (CMML), or low-blast acute myelogenous leukemia (LB AML) (NCT02610777)

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Background: P, the first and only small-molecule inhibitor of the NEDD8-activating enzyme, disrupts proteasomal degradation of select proteins and has shown promising clinical activity and good tolerability in combination with A in AML. Methods: 120 pts with higher-risk (Revised International Prognostic Scoring System risk > 3) MDS/CMML or LB AML naïve to hypomethylating agents were randomized 1:1 to receive P 20 mg/m2 intravenously (IV) on days (d) 1, 3, 5 + A 75 mg/m2 (IV/subcutaneously) on d 1–5, 8, 9 (n = 58), or A alone (n = 62), in 28-d cycles until unacceptable toxicity, relapse, transformation to AML, or progression. The primary endpoint was overall survival (OS), although the study was underpowered for OS. Results: Baseline characteristics were generally balanced between arms. Pts received a median of 13.0 vs 8.5 cycles of P+A vs A. Median OS in the intent-to-treat (ITT) population with P+A vs A (n = 120) was 21.8 vs 19.0 mos (hazard ratio [HR] 0.80; 95% CI 0.51–1.26; P = .334; median follow-up 21.4 vs 19.0 mos). Subanalyses showed median OS with P+A vs A in higher-risk MDS (n = 67) of 23.9 vs 19.1 mos (HR 0.70; 95% CI 0.39–1.27; P = .240) and in LB AML (n = 36) of 23.6 vs 16.0 mos; HR 0.49; 95% CI 0.22–1.11; P = .081). Event-free survival (EFS – time from randomization to death/transformation to AML) with P+A vs A trended longer in the ITT population (median 21.0 vs 16.6 mos; HR 0.65; 95% CI 0.41–1.02; P = .060) and was significantly longer in higher-risk MDS (median 20.2 vs 14.8 mos; HR 0.54; 95% CI 0.29–1.00; P = .045). In response-evaluable pts, overall response rate was 71% (n = 39/55; 46% complete remission [CR] + CR with incomplete blood count recovery [CRi], 5% partial response [PR], 20% hematologic improvement [HI]) with P+A vs 60% (n = 32/53; 38% CR+CRi, 8% PR, 15% HI) with A. In higher-risk MDS, CR rate was 52% vs 27% ( P = .050) with P+A vs A. Median A dose intensity was 97% vs 98% with P+A vs A. Rates of grade ≥3 adverse events were 90% vs 87% with P+A vs A; the most common were 31% vs 27% neutropenia, 26% vs 29% febrile neutropenia, 19% vs 27% anemia, and 19% vs 23% thrombocytopenia. On-study deaths occurred in 9% of P+A pts and 16% of A pts. Conclusions: P+A had a comparable safety profile to A alone, did not increase myelosuppression, and maintained A dose intensity. Although not statistically significant, P+A increased OS, EFS, and response rates vs A, particularly in pts with higher-risk MDS. Further evaluation of P+A vs A is ongoing in a randomized phase. Clinical trial information: NCT02610777 .

Immune Checkpoint Inhibitors in AML-A New Frontier

Despite recent therapeutic advancements, acute myeloid leukemia (AML) remains a challenging clinical entity with overall poor outcomes. Given the evident role of T cell-mediated immunity in response to allogeneic stem cell transplantation and donor lymphocyte infusions, strategies that enhance immune activation and mitigate immune dysfunction represent attractive therapeutic platforms to improve clinical outcomes in AML. Pre-clinical data suggest that immune dysfunction is a major contributor to AML progression and relapse. Increased expression of immune checkpoints such as programmed death 1 (PD-1) contributes to AML immune evasion and is associated with disease progression. Immune checkpoint inhibition is being explored in AML with early evidence of clinical activity, particularly in combination with cytotoxic chemotherapy and hypomethylating agents. In this review, we explore the scientific rationale behind the use of immune checkpoint inhibition either as single agents or in combination with hypomethylating agents or cytotoxic chemotherapy and provide a clinical update of both completed and ongoing trials in AML.

Advances in Genomic Profiling and Risk Stratification in Acute Myeloid Leukemia

OBJECTIVE

To review the current state of molecular and genetic profiling of acute myeloid leukemia (AML) and its implications.

DATA SOURCE

Peer-reviewed journal articles.

CONCLUSION

Significant advances in the understanding of the pathology of acute myeloid leukemia have led to refined risk stratification of patients and application of novel targeted therapies based on genetic profiles. Minimal residual disease testing allows for highly sensitive disease surveillance that can be used to predict relapse and assess treatment response.

IMPLICATIONS FOR NURSING PRACTICE

Accurate prognostication and therapeutic decision-making for patients with acute myeloid leukemia is dependent on molecular profiling. Being knowledgeable of the implications of minimal residual disease testing is critical for patient-centered care.

Myeloid sarcoma manifesting as generalized lymphadenopathy in a patient with myelofibrosis

Immunophenotyping is critical to the diagnosis of MS, as it can be difficult to differentiate from other diagnoses including lymphoma using conventional light microscopy.

Cyclin-dependent kinase (CDK) 9 and 4/6 inhibitors in acute myeloid leukemia (AML): a promising therapeutic approach

Introduction: Despite advancements over the last 2 years, outcomes for acute myeloid leukemia (AML) are poor; however, a greater comprehension of disease mechanisms has driven the investigation of new targeted treatments. Cyclin-dependent kinases (CDKs) regulate cell cycle progression, transcription and DNA repair, and are aberrantly expressed in AML. Targeting the CDK pathway is an emerging promising therapeutic strategy in AML.Areas covered: We describe the rationale for targeting CDK9 and CDK4/6, the ongoing preclinical and clinical trials and the potential of these inhibitors in AML. Our analysis included an extensive literature search via the Pubmed database and clinicaltrials.gov (March to August, 2019).Expert opinion: While CDK4/6 inhibitors are early in development for AML, CDK9 inhibition with alvocidib has encouraging clinical activity in newly diagnosed and relapsed/refractory AML. Preclinical data suggests that leukemic MCL-1 dependence may predict response to alvocidib. Moreover, MCL-1 plays a key role in resistance to BCL-2 inhibition with venetoclax. Investigational strategies of concomitant BCL-2 and CDK9 inhibition represent a promising therapeutic platform for AML. Furthermore, preclinical data suggests that CDK4/6 inhibition has selective activity in patients with KMT2A-rearrangements and FLT3 mutations. Incorporation of CDK9 and 4/6 inhibitors into the existing therapeutic armamentarium may improve outcomes in AML.

Signatures of CD8+ T cell dysfunction in AML patients and their reversibility with response to chemotherapy

BACKGROUND

Our understanding of phenotypic and functional signatures of CD8+ T cell dysfunction in acute myeloid leukemia (AML) is limited. Deciphering these deranged T cell functional states and how they are impacted by induction chemotherapy is essential for incorporation of novel immune-based strategies to restore and maintain antileukemia immunity.

METHODS

We utilized high-dimensional immunophenotyping, gene expression, and functional studies to characterize peripheral blood and bone marrow CD8+ T cells in 72 AML patients at diagnosis and after induction chemotherapy.

RESULTS

Our data suggest that multiple aspects of deranged T cell function are operative in AML at diagnosis, with exhaustion and senescence being the dominant processes. Following treatment, the phenotypic and transcriptional profile of CD8+ T cells diverged between responders and nonresponders. Response to therapy correlated with upregulation of costimulatory, and downregulation of apoptotic and inhibitory, T cell signaling pathways, indicative of restoration of T cell function. In functional studies, AML blasts directly altered CD8+ T cell viability, expansion, co-signaling and senescence marker expression. This CD8+ T cell dysfunction was in part reversible upon PD-1 blockade or OX40 costimulation in vitro.

CONCLUSION

Our findings highlight the uniqueness of AML in sculpting CD8+ T cell responses and the plasticity of their signatures upon chemotherapy response, providing a compelling rationale for integration of novel immunotherapies to augment antileukemia immunity.

FUNDING

This work was supported by the Leukemia & Lymphoma Society grant no. 6449-13; NIH grants UM1-CA186691 and R01-HL110907-01; the American Society for Blood and Marrow Transplantation New Investigator Award/Gabrielle's Angel Foundation; the Vienna Fund for Innovative Cancer Research; and by fellowships from the Wenner-Gren Foundation and the Swedish Society for Medical Research.

Signatures of CD8+ T cell dysfunction in AML patients and their reversibility with response to chemotherapy

BACKGROUND

Our understanding of phenotypic and functional signatures of CD8+ T cell dysfunction in acute myeloid leukemia (AML) is limited. Deciphering these deranged T cell functional states and how they are impacted by induction chemotherapy is essential for incorporation of novel immune-based strategies to restore and maintain antileukemia immunity.

METHODS

We utilized high-dimensional immunophenotyping, gene expression, and functional studies to characterize peripheral blood and bone marrow CD8+ T cells in 72 AML patients at diagnosis and after induction chemotherapy.

RESULTS

Our data suggest that multiple aspects of deranged T cell function are operative in AML at diagnosis, with exhaustion and senescence being the dominant processes. Following treatment, the phenotypic and transcriptional profile of CD8+ T cells diverged between responders and nonresponders. Response to therapy correlated with upregulation of costimulatory, and downregulation of apoptotic and inhibitory, T cell signaling pathways, indicative of restoration of T cell function. In functional studies, AML blasts directly altered CD8+ T cell viability, expansion, co-signaling and senescence marker expression. This CD8+ T cell dysfunction was in part reversible upon PD-1 blockade or OX40 costimulation in vitro.

CONCLUSION

Our findings highlight the uniqueness of AML in sculpting CD8+ T cell responses and the plasticity of their signatures upon chemotherapy response, providing a compelling rationale for integration of novel immunotherapies to augment antileukemia immunity.

FUNDING

This work was supported by the Leukemia & Lymphoma Society grant no. 6449-13; NIH grants UM1-CA186691 and R01-HL110907-01; the American Society for Blood and Marrow Transplantation New Investigator Award/Gabrielle's Angel Foundation; the Vienna Fund for Innovative Cancer Research; and by fellowships from the Wenner-Gren Foundation and the Swedish Society for Medical Research.

Conjugation of haematopoietic stem cells and platelets decorated with anti-PD-1 antibodies augments anti-leukaemia efficacy

Patients with acute myeloid leukaemia who relapse following therapy have few treatment options and face poor outcomes. Immune checkpoint inhibition, for example, by antibody-mediated programmed death-1 (PD-1) blockade, is a potent therapeutic modality that improves treatment outcomes in acute myeloid leukaemia. Here, we show that systemically delivered blood platelets decorated with anti-PD-1 antibodies (aPD-1) and conjugated to haematopoietic stem cells (HSCs) suppress the growth and recurrence of leukaemia in mice. Following intravenous injection into mice bearing leukaemia cells, the HSC-platelet-aPD-1 conjugate migrated to the bone marrow and locally released aPD-1, significantly enhancing anti-leukaemia immune responses, and increasing the number of active T cells, production of cytokines and chemokines, and survival time of the mice. This cellular conjugate also promoted resistance to re-challenge with leukaemia cells. Taking advantage of the homing capability of HSCs and in situ activation of platelets for the enhanced delivery of a checkpoint inhibitor, this cellular combination-mediated drug delivery strategy can significantly augment the therapeutic efficacy of checkpoint blockade.

A Multi-center Phase I Trial of Ipilimumab in Patients with Myelodysplastic Syndromes following Hypomethylating Agent Failure

Purpose: After failure of hypomethylating agents (HMA), patients with myelodysplastic syndromes (MDS) have dismal survival and no approved treatment options.Patients and Methods: We conducted a phase 1b investigator-initiated trial of ipilimumab in patients with higher risk MDS who have failed HMAs. Patients received monotherapy at two dose levels (DL; 3 and 10 mg/kg) with an induction followed by a maintenance phase. Toxicities and responses were evaluated with CTCAE.4 and IWG-2006 criteria, respectively. We also performed immunologic assays and T-cell receptor sequencing on serial samples.Results: Twenty-nine patients from 7 centers were enrolled. In the initial DL1 (3 mg), 3 of 6 patients experienced grade 2-4 immune-related adverse events (IRAE) that were reversible with drug discontinuation and/or systemic steroids. In DL2, 4 of 5 patients experienced grade 2 or higher IRAE; thus, DL1 (3 mg/kg) was expanded with no grade 2-4 IRAEs reported in 18 additional patients. Best responses included marrow complete response (mCR) in one patient (3.4%). Prolonged stable disease (PSD) for ≥46 weeks occurred in 7 patients (24% of entire cohort and 29% of those treated with 3 mg/kg dose), including 3 patients with more than a year of SD. Five patients underwent allografting without excessive toxicity. Median survival for the group was 294 days (95% CI, 240-671+). Patients who achieved PSD or mCR had significantly higher frequency of T cells expressing ICOS (inducible T-cell co-stimulator).Conclusions: Our findings suggest that ipilimumab dosed at 3 mg/kg in patients with MDS after HMA failure is safe but has limited efficacy as a monotherapy. Increased frequency of ICOS-expressing T cells might predict clinical benefit. Clin Cancer Res; 24(15); 3519-27. ©2018 AACR.

A Comparison of Clofarabine-based (GCLAC) and Cladribine-based (CLAG) Salvage Chemotherapy for Relapsed/Refractory AML

BACKGROUND

Salvage regimens for patients with relapsed/refractory acute myeloid leukemia (rrAML) lack comparative data for superiority. Thus, we conducted a retrospective analysis of clofarabine-based (GCLAC; granulocyte colony-stimulating factor [filgrastim], clofarabine, high-dose cytarabine) versus cladribine-based (CLAG; cladribine, cytarabine, granulocyte colony-stimulating factor [filgrastim]) regimens in rrAML.

PATIENTS AND METHODS

We identified 41 consecutive patients with rrAML who had received either GCLAC or CLAG from 2011 to 2014. The primary outcome measure was the complete remission (CR) rate defined according to the International Working Group criteria. The secondary outcomes included the proportion of patients who underwent allogenic stem cell transplantation and the rate of relapse-free survival and overall survival.

RESULTS

We found no significant differences in the baseline characteristics of the patients treated with GCLAC (n = 22) or CLAG (n = 19). The outcomes with these 2 regimens were not significantly different. Patients treated with GCLAC had a CR/CR with incomplete blood count recovery rate of 64% compared with 47% for the patients treated with CLAG (P = .36). Of the GCLAC patients, 45% underwent allogeneic stem cell transplantation compared with 26% of the CLAG patients (P = .32). The median relapse-free survival after GCLAC and CLAG was 1.59 years and 1.03 years, respectively (P = .75). The median overall survival after GCLAG and CLAG was 1.03 years and 0.70 years, respectively (P = .08). The drug costs were significantly different for GCLAC versus CLAG. Using an average wholesale price, the cost per patient per cycle was $60,821.60 for GCLAC and $4910.60 for CLAG.

CONCLUSION

A single-institutional retrospective analysis found no significant differences in the outcomes between GCLAC and CLAG for rrAML patients, although formal comparisons should be performed in a randomized clinical trial. The cost of GCLAC was greater than that of CLAG, which should be considered when evaluating the choice for the salvage chemotherapy options.

A phase I trial of ipilimumab (ipi) in patients (pts) with myelodysplastic syndromes (MDS) after hypomethylating agent (HMAs) failure

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Background: Pts with HR-MDS after HMA failure have a poor overall survival (OS) of < 6 months. Immune escape is associated with resistance to HMAs in MDS. We hypothesized that CTLA-4 blockade in these pts would be tolerable and lead to clinical responses. Methods: This investigator-initiated, CTEP-sponsored, multi-center phase 1b study enrolled pts after failure of HMAs. In dose-escalation, ipi monotherapy was given at 2 dose levels (DL): 3 and 10mg/kg. Four doses (every 3 weeks) were administered followed by a maintenance phase (4 doses every 3 months) for non-porgressors. Toxicities and responses were evaluated with CTCAE4 and IWG2006 criteria, respectively. OS was estimated using the Kaplan-Meier method. The impact on T-cells were studied by flow cytometry and TCR sequencing. Results: 29 pts from 7 centers were enrolled. Mean age (SD) was 67 (8) years. Most had IPSS high/int-2 (55%), 45% had int-1. Three of 6 pts in DL1 and 4 of 5 pts in DL2 experienced grade [G]2-4 immune-related adverse events [IRAEs] that were reversible with drug discontinuation or systemic steroids. The DL1 (3mg/kg) was expanded with no G2-4 IRAEs reported in the 18 additional pts. A total of 15 deaths occurred due to disease progression or other complications but none attributed to ipilimumab. In total, 52% received all 4 induction doses, and 24% received ≥1 maintenance dose. Best objective responses were 2 marrow complete responses (mCR, 7%). Prolonged stable disease (PSD) for ≥46 weeks occurred in 6 pts (21%) and for ≥54 weeks in 3 pts (10%). Five pts (17%) subsequently underwent allogeneic transplantation (alloSCT) without evidence of excessive toxicity. Median OS (censoring at alloSCT) was 294 days (95%CI, 240-671+) and 400 days (95%CI, 240-671+) for those who received maintenance (n = 7). Pts who achieved PSD and mCR had significantly increased expression of ICOS, a marker of T-cell activation. Conclusions: Immune checkpoint blockade with ipi is tolerable and can lead to PSD/mCR in a proportion of pts. However, ipi monotherapy efficacy is limited after HMA failure and combination-based approaches should be considered. Increased frequencies of ICOS expression might predict clinical benefit. Clinical trial information: NCT01757639.

Association of acute myeloid leukemia's most immature phenotype with risk groups and outcomes

The precise phenotype and biology of acute myeloid leukemia stem cells remain controversial, in part because the "gold standard" immunodeficient mouse engraftment assay fails in a significant fraction of patients and identifies multiple cell-types in others. We sought to analyze the clinical utility of a novel assay for putative leukemia stem cells in a large prospective cohort. The leukemic clone's most primitive hematopoietic cellular phenotype was prospectively identified in 109 newly-diagnosed acute myeloid leukemia patients, and analyzed against clinical risk groups and outcomes. Most (80/109) patients harbored CD34(+)CD38(-) leukemia cells. The CD34(+)CD38(-) leukemia cells in 47 of the 80 patients displayed intermediate aldehyde dehydrogenase expression, while normal CD34(+)CD38(-) hematopoietic stem cells expressed high levels of aldehyde dehydrogenase. In the other 33/80 patients, the CD34(+)CD38(-) leukemia cells exhibited high aldehyde dehydrogenase activity, and most (28/33, 85%) harbored poor-risk cytogenetics or FMS-like tyrosine kinase 3 internal tandem translocations. No CD34(+) leukemia cells could be detected in 28/109 patients, including 14/21 patients with nucleophosmin-1 mutations and 6/7 acute promyelocytic leukemia patients. The patients with CD34(+)CD38(-) leukemia cells with high aldehyde dehydrogenase activity manifested a significantly lower complete remission rate, as well as poorer event-free and overall survivals. The leukemic clone's most immature phenotype was heterogeneous with respect to CD34, CD38, and ALDH expression, but correlated with acute myeloid leukemia risk groups and outcomes. The strong clinical correlations suggest that the most immature phenotype detectable in the leukemia might serve as a biomarker for "clinically-relevant" leukemia stem cells. ClinicalTrials.gov: NCT01349972.

Phase I Clinical Trials in Acute Myeloid Leukemia: 23-Year Experience From Cancer Therapy Evaluation Program of the National Cancer Institute

BACKGROUND

Therapy for acute myeloid leukemia (AML) has largely remained unchanged, and outcomes are unsatisfactory. We sought to analyze outcomes of AML patients enrolled in phase I studies to determine whether overall response rates (ORR) and mortality rates have changed over time.

METHODS

A retrospective analysis was performed on 711 adult AML patients enrolling in 45 phase I clinical trials supported by the Cancer Therapy Evaluation Program of the National Cancer Institute from 1986 to 2009. Changes in ORR and mortality rates for patients enrolled in 1986 to 1990, 1991 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009 were estimated with multivariable logistic regression models. All statistical tests were two-sided.

RESULTS

There was a statistically significant increase in AML patients enrolling in phase I clinical trials over time (1986 to 1990: n = 61; 2006 to 2009: n = 256; P = .03). The ORR for the entire cohort was 15.4% (1986 to 1990: 8.9%, 1991 to 1995: 21.1%; 1996 to 2000: 7.0%; 2001 to 2005: 10.0%; 2006 to 2009: 22.6%), and it statistically significantly improved over time (P < .001). There was a statistically significant improvement in ORRs with novel agents in combination vs single agents (ORR = 22.8% vs 4.7%, respectively, odds ratio = 5.95, 95% confidence interval = 3.22 to 11.9, P < .001). The 60-day mortality rate for the entire cohort was 22.6%, but it statistically significantly improved over time (P = .009).

CONCLUSIONS

There has been an encouraging increase in AML patients enrolling in phase I clinical studies over time. The improvement in ORRs appears to be partly because of the increase in combination trials and the inclusion of previously untreated poor-risk AML. Continued enrollment of AML patients in early phase clinical trials is vital for drug development and improvement in therapeutic outcomes.

Clinical activity of alvocidib (flavopiridol) in acute myeloid leukemia

There have been minimal therapeutic advancements in acute myeloid leukemia (AML) over the past 4 decades and outcomes remain unsatisfactory. Alvocidib (formerly flavopiridol) is a multi-serine threonine cyclin-dependent kinase inhibitor with demonstrable in vitro and clinical activity in AML when combined in a timed sequential chemotherapy regimen, FLAM (alvocidib followed by cytarabine continuous infusion and mitoxantrone). FLAM has been evaluated in sequential phase 1 and phase 2 studies in 149 and 256 relapsed/refractory and newly diagnosed non-favorable risk AML patients, respectively, with encouraging findings in both patient populations warranting further investigation. This review highlights the mechanism of action of alvocidib, pre-clinical studies of alvocidib in AML, and the clinical trials evaluating alvocidib alone and in combination with cytotoxic agents (FLAM) in AML.

Randomized multicenter phase II study of flavopiridol (alvocidib), cytarabine, and mitoxantrone (FLAM) versus cytarabine/daunorubicin (7+3) in newly diagnosed acute myeloid leukemia

Serial studies have demonstrated that induction therapy with FLAM [flavopiridol (alvocidib) 50 mg/m(2) days 1-3, cytarabine 667 mg/m(2)/day continuous infusion days 6-8, and mitoxantrone (FLAM) 40 mg/m(2) day 9] yields complete remission rates of nearly 70% in newly diagnosed poor-risk acute myeloid leukemia. Between May 2011-July 2013, 165 newly diagnosed acute myeloid leukemia patients (age 18-70 years) with intermediate/adverse-risk cytogenetics were randomized 2:1 to receive FLAM or 7+3 (cytarabine 100 mg/m(2)/day continuous infusion days 1-7 and daunorubicin 90 mg/m(2) days 1-3), across 10 institutions. Some patients on 7+3 with residual leukemia on day 14 received 5+2 (cytarabine 100 mg/m(2)/day continuous infusion days 1-5 and daunorubicin 45 mg/m(2) days 1-2), whereas patients on FLAM were not re-treated based on day 14 bone marrow findings. The primary objective was to compare complete remission rates between one cycle of FLAM and one cycle of 7+3. Secondary end points included safety, overall survival and event-free survival. FLAM led to higher complete remission rates than 7+3 alone (70% vs. 46%; P=0.003) without an increase in toxicity, and this improvement persisted after 7+3+/-5+2 (70% vs. 57%; P=0.08). There were no significant differences in overall survival and event-free survival in both arms but post-induction strategies were not standardized. These results substantiate the efficacy of FLAM induction in newly diagnosed AML. A phase III study is currently in development. This study is registered with clinicaltrials.gov identifier: 01349972.