Cyclacel LTD Research Articles

A Randomised Evaluation of Low-Dose Ara-C Plus BCT-100 Versus Low Dose Ara-C in Older Patients with Acute Myeloid Leukaemia: Results from the LI-1 Trial

Background: Among patients with Acute Myeloid Leukaemia (AML) over the age of 60, a considerable number are not considered suitable for intensive remission-induction chemotherapy. Survival in these patients is poor, whether they are treated using hypomethylating agents or low-dose ara-C (LDAC). The possibility of combination therapy with additional agents represents an attractive option. Arginine metabolism plays a key role in AML pathogenesis (Mussai et al. Blood 2013); BCT-100 is a pegylated recombinant human arginase that leads to a rapid depletion in extracellular and intracellular arginine concentrations resulting in G0/G1 arrest, and subsequent death by necrosis. BCT-100 demonstrates significant activity as single-agent against AML cell lines, AML xenografts and primary AML blasts from newly diagnosed or relapsed patients (Mussai et al. Blood 2015). Importantly BCT-100 is synergistic in combination with cytarabine.Aims: To assess the efficacy of LDAC+BCT100 versus LDAC alone in patients aged 60+ unsuitable for intensive therapy, in a “pick a winner” design. This design allows several treatments to be assessed simultaneously in a randomised fashion, with the aim of doubling 2-year survival from 11% to 22% (HR 0.69), with interim assessments after 50 and 100 patients per arm are recruited.Methods: LDAC was given at 20mg BD SC on days 1-10 of each course. Patients randomised to the combination received LDAC as above with BCT-100 1600U/kg on Days 1, 8, 15 and 22 as a 1-hour intravenous infusion. Courses occurred at 4-6 week intervals. Toxicities were recorded using CTCAE version 3. Pharmacokinetic and biomarker samples were assessed in BCT-100 patients. Results here are based upon median follow-up of 3.8 months (range: 0.1 - 20.6 months)Results: Between September 2018 and December 2020, 83 patients were randomised. The trial was prematurely closed due to the COVID pandemic and did not reach the pre-planned first evaluation. Median age was 76.7 years (range 62-88). Overall, 65% were male; 70% de novo AML, 23% secondary AML, and 6% high risk MDS; 2% favourable, 59% intermediate, 23% adverse and 15% unknown/unreported cytogenetics. Median of 2 courses was delivered in either arm (mean 2 LDAC, 2 LDAC+BCT, range for both: 1-12). BCT-100 leads to a depletion of arginine from baseline in the majority of patients.Overall response (CR/CRi) was achieved in 12/81 patients (15%), (LDAC+BCT-100 15%, LDAC 15%, R 1.03 (0.30, 3.51),P=0.963). Thirty-day mortality was not significantly increased (18% vs 11%, HR 1.71 (0.50, 5.84), P=0.393; and 1-year survival showed no evidence of a difference (31% vs 30%, HR 1.28 (0.72, 2.25). Median overall survival time was 3.8 vs 6.4months; overall survival HR 1.11 (0.64, 1.90), P=0.715. The most common cause of death was resistant/recurrent disease: 12(46%) vs 16(59%). BCT-100 was not associated with any haematological toxicity; although rare grade 3/4 cardiac and hepatic events were reported, these were not significantly increased with BCT-100.Summary: The addition of BCT-100 to LDAC did not improve response rate or survival. BCT-100 was well tolerated with an acceptable toxicity profile. Further clinical evaluation of BCT-100 induced arginase depletion continues in a variety of malignancies.Acknowledgements: We are grateful to Blood Cancer UK for funding the trial and Bio-Cancer Treatment International for providing drug and additional support for this Investigator Initiated Study.Figure 1. OS All patients [Display omitted] DisclosuresKnapper: Jazz: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Astellas: Ended employment in the past 24 months, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. McMullin: Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial support, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan: Research Funding, Speakers Bureau. Copland: Incyte: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Cyclacel Ltd: Research Funding; Astellas: Honoraria, Speakers Bureau; Jazz: Honoraria, Speakers Bureau. Russell: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Jazz: Research Funding, Speakers Bureau.

A Randomised Evaluation of Low-Dose Cytarabine Arabinoside Plus Lenalidomide Versus Single-Agent Low-Dose Cytarabine Arabinoside in Older Patients with Acute Myeloid Leukaemia: Results from the LI-1 Trial

Background: Many patients with Acute Myeloid Leukemia (AML) diagnosed after 60 years of age are not considered suitable for intensive remission induction chemotherapy, either due to co-morbidities or frailty associated with advanced age. Despite treatment with either a hypomethylating agent or low-dose cytarabine arabinoside (LDAC), survival is usually poor, with 1-year survival after LDAC of 24-37% in NCRI AML16 and historical arms of LI-1. Combination therapy with additional agents represents an attractive option, and has the potential to improve patient outcomes without substantially increasing toxicity. Lenalidomide (Revlimid TM) is an immunomodulatory drug, used to treat myeloma, and some cases of myelodysplastic syndrome, and has potent antineoplastic, anti-angiogenic, anti-inflammatory and pro-erythropoietic properties. Early-phase trials of lenalidomide in AML have demonstrated clinical activity with acceptable toxicity.Aim: To assess the efficacy and tolerability of LDAC+lenalidomide versus LDAC alone in patients aged 60+ unsuitable for intensive therapy. The aim was to double 2-year survival from 11% to 22% (HR 0.69).Methods: LI-1 was an international multicentre, multi-arm, randomised phase II trial developed to study the efficacy and tolerability of novel non-intensive therapies in AML using a “pick a winner” design. LDAC was given at 20mg BD SC on days 1-10 of each course. Lenalidomide was administered orally once daily in a flat 10mg dose for 21 days, where day 1 is day 1 of LDAC with courses occurring at 5-week intervals for courses 1-4. Patients considered to be benefitting after 4 courses, i.e. in remission or stable disease, could continue to receive treatment until disease progression, either with LDAC+lenalidomide at 6-week intervals, or lenalidomide only at 4-week intervals if patient had experienced significant toxicity. Toxicities were recorded using CTCAEv3. Primary objectives included overall survival (OS), complete remission (CR + CRi) achievement, reasons for failure, duration of response (CR/CRi), relapse rates and deaths in first CR. Secondary objectives included toxicity, supportive care requirements, and Quality of Life assessments (measured using EORTC QLQ-30, EQ5D and HADS tools).Results: Between Jan-17 and Jun-19, 202 patients from Denmark (8%), New Zealand (16%) and the UK (76%) were randomised. Median age was 78 years (range 62-89). Overall, 58% were male; 76% de novo AML, 20% secondary AML, and 4% high risk MDS; 1% favourable, 66% intermediate, 19% adverse and 14% unknown cytogenetics; WHO performance status 0 for 15%, 1 for 58%, 2 for 22% and 3 for 5%. Median of 2 courses (range 0-24; mean 3.28) was delivered in LDAC arm and 1 course in LDAC+lenalidomide arm (range 0-25; mean 3.48).Overall response (CR/CRi) was achieved in 40/202 patients (20%), (LDAC+lenalidomide 25%, LDAC 14%, OR 0.45 (0.22, 0.93), P=0.031). 30-day mortality was not significantly increased (19% in both arms); and 2-year OS showed no significant difference (14% vs 11.5%, HR 0.94 (0.69, 1.29, P=0.719). Median OS was 3.5 vs 4.6 months; HR 0.96 (0.71, 1.30), P=0.80. 1-year OS for patients that didn't enter CR/CRi was 6.8% for LDAC+lenalidomide vs 16.9% for LDAC (P=0.028). Cause of death for the majority of patients was resistant/recurrent disease: 45(53%) vs 47(58%). Most adverse events (AEs) were grade 1/2 in both arms. During cycle 1, there were 78 vs 51 grade 3/4 AEs in the LDAC+lenalidomide and LDAC arms, respectively (P=0.02). This included 5 thrombotic events in the LDAC+lenalidomide arm (4 grade 3 and 1 grade 4) and none in the LDAC arm. In course 1, supportive care requirements were higher in terms of both days of antibiotics (7 vs 3; p=0.001) and hospitalisation days (11 vs 6.5; p=0.005) for the LDAC+lenalidomide arm. There was no difference in transfusion requirements.Conclusions: Despite improving the CR/CRi rate, the combination of lenalidomide+LDAC did not improve OS, relapse-free survival or time in remission in elderly patients with AML. The addition of lenalidomide to LDAC resulted in increased toxicity, including episodes of thrombosis, as well as increased supportive care requirements. Alternative strategies to improve survival for elderly patients with AML remain a significant clinical need.Acknowledgements: We are grateful to Blood Cancer UK for funding the trial and Celgene for providing drug and additional support for this IIS.Fig 1: OS All patients [Display omitted] DisclosuresCopland: Astellas: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Incyte: Honoraria, Research Funding, Speakers Bureau; Jazz: Honoraria, Speakers Bureau; Cyclacel Ltd: Research Funding. Russell: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Jazz: Research Funding, Speakers Bureau. OffLabel Disclosure:Off label use of lenalidomide in combination with low dose cytarabine will be discussed in the setting of elderly unfit AML.

Ponatinib in Combination with FLAG-IDA Chemotherapy for Blast-Phase Chronic Myeloid Leukemia: Final Results of the Seamless Phase I/II Dose-Finding UK Trials Acceleration Programme (TAP) Matchpoint Trial

BackgroundOutcomes for patients with blast-phase chronic myeloid leukaemia (BP-CML) are extremely poor, and allogeneic stem cell transplantation (alloSCT) represents the only opportunity for cure. Crucially, long-term survival post-transplant depends on first attaining a return to chronic phase though salvage treatment. Novel strategies that improve response and can optimise transplant outcomes are therefore required. In the era of tyrosine kinase inhibitors (TKIs), BP-CML has become an orphan disease. Consequently, the prospective trials needed to guide clinical practice are rarely attempted. We now report the final results of the prospective MATCHPOINT trial which uses an innovative EffTox design to investigate the activity and tolerability of the TKI ponatinib in combination with high-dose chemotherapy, to improve remission status and transplant outcomes in BP-CML.Methods and patientsBetween March 2015 and April 2018, 17 patients were recruited through the UK Trials Acceleration Programme to this dose-finding, seamless phase I/II trial of daily ponatinib combined with fludarabine, cytarabine, granulocyte colony-stimulating factor and idarubicin (PON-FLAG-IDA) salvage therapy. We employed EffTox, an advanced Bayesian method to simultaneously consider response to treatment (efficacy) and dose-limiting toxicity (DLT) in all treated patients, providing a single measure of clinical utility, which then informed the subsequent dose level recommendation. The primary objective was to determine the optimal dose of ponatinib, in combination with chemotherapy, as determined by the EffTox model. The primary outcomes were attainment of a second chronic phase and occurrence of a DLT. Secondary outcomes investigated the toxicity of combination therapy, alloSCT outcomes, and survival. The median follow-up of trial patients is 41 months.ResultsNine patients completed one cycle of PON-FLAG-IDA, a further eight patients completed both planned cycles. Using an EffTox analysis, the optimal dose of ponatinib was determined as 30mg once daily. Eleven patients achieved a return to chronic phase and four experienced a DLT, fulfilling the pre-specified criteria for clinically relevant efficacy and toxicity. After PON-FLAG-IDA salvage, eight patients attained complete cytogenetic response and five major molecular response (MMR). The most common grade 3-4 non-hematologic toxicities were febrile neutropenia (29% of patients), lung infection (24%), fever (18%) and hypocalcaemia (18%). Three patients experienced treatment-related mortality. Twelve patients proceeded to alloSCT, of whom seven are alive after median 36 months post-transplant follow-up. Only one of the five patients achieving MMR relapsed post-alloSCT, neither of the other relapsing patients achieved a second chronic phase pre-transplant. Median overall survival (OS) of the whole cohort was 12 months (95% confidence interval 6 months to non-calculable), median OS of patients undergoing alloSCT has not been reached.ConclusionsPonatinib has shown that it can be safely combined with high-dose chemotherapy to achieve a return to chronic phase in patients with BP-CML, and represents an effective novel treatment strategy in this high-risk population. Responding patients subsequently undergoing alloSCT can benefit from long-term disease-free survival. The EffTox method enabled very efficient data usage from this high-risk patient population, and is a model for investigating novel therapies in other ultra-orphan cancers.Figure: Overall survival of the MATCHPOINT cohort [Display omitted] DisclosuresCopland: Incyte: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Jazz: Honoraria, Speakers Bureau; Astellas: Honoraria, Speakers Bureau; Cyclacel Ltd: Research Funding. Byrne: Incyte: Honoraria. Rothwell: Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria; Daiichi Sankyo: Honoraria. Brock: Eli Lily: Honoraria; Invex Therapeutics: Honoraria; Merck: Honoraria; Roche: Honoraria; AstraZeneca: Current holder of individual stocks in a privately-held company; GSK: Current holder of individual stocks in a privately-held company. De Lavallade: Pfizer, Novartis.: Honoraria; Bristol Myers Squibb, Incyte: Honoraria, Research Funding. Craddock: Novartis Pharmaceuticals: Other: Advisory Board ; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding. Clark: Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria. Smith: Daiichi Sankyo: Speakers Bureau; Pfizer: Speakers Bureau; ARIAD: Honoraria. Milojkovic: Novartis: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Incyte: Honoraria, Speakers Bureau. Yap: Faron Pharmaceuticals: Honoraria; Celgene: Honoraria. OffLabel Disclosure:Ponatinib for the treatment of blast-phase CML

Uncoupling p53 from an Embryonic Regulome Exhausts Quiescent CML Stem Cells through Inhibition of a HIF1alpha Molecular Program

Although it has been recognized for many years that cancer stem cells and embryonic stem cells (ESC) share molecular features, identifying ways to exploit this therapeutically has proved challenging. To date, these shared features have not been examined in the leukemic stem cells (LSC) found in patients with chronic myeloid leukemia (CML).By integrating known ES regulatory circuitry with transcriptomics datasets, including deep single-cell RNA-seq profiling of 15,670 LSC from five patients with CML, we identified a core ESC regulome in the LSC containing 1243 genes. The significant majority of this regulome (1102 genes) was up-regulated in cycling LSC, whilst quiescent LSC showed up-regulation of a characteristic set of 101 genes, unique to cells with high ESC identity and with regulatory circuitry enriched for c-Myc and Nanog modules. Membership of the ESC regulome included the TP53 gene which was transcriptionally repressed and detected at a lower frequency in quiescent LSC compared to cycling ones (11.8% vs 43.6%). We also demonstrated that tyrosine kinase inhibitors (TKI) repress the ESC regulome and TP53 expression in LSC, suggesting that the regulome safeguards against high levels of TP53 expression, thus promoting survival of quiescent LSC in the presence of TKI. We hypothesized that overcoming the influence of the regulome on TP53 expression would provide an opportunity to eradicate quiescent LSC.To this end, we used an MDM2 inhibitor (MDM2i), RG7388 (idasanutlin) or RG7112, to stabilize the p53 protein, examining its potential in combination with nilotinib (NIL) to eradicate CML LSC in vitro and in vivo, with RG7388 being the most optimized and furthest in development. The combination of NIL plus MDM2i in vitro was more effective at targeted LSC from primary patient samples than NIL treatment alone, as evidenced by reduced CFC and LTC-IC outputs (p<0.05, 0.01 respectively). Intriguingly, the combination of NIL plus MDM2i did not result in significant reductions in the number of LSC compared to NIL only, when we quantified them at the end of drug treatments in pre-clinical mouse models. Instead, we observed a functional decline of the LSC as evidenced by diminished engraftment potential in 2 o recipient mice (p<0.05; SCLtTA x BCR-ABL1 transgenic model) or diminished colony-plating potential (p<0.05). This was followed by near complete depletion of the LSC population (p<0.05) 28 days after cessation of combination drug treatment (patient-derived xenografts/PDX in immunocompromised mice).In order to understand the molecular events underpinning these drug effects on LSC, we performed RNA-seq analysis of drug-treated CD34 + cells in vitro (bulk cells), or of human CD34 + cells obtained from PDX (single cell RNA-seq). CD34 + cells treated with NIL plus MDM2i in vitro showed evidence of increased p53 stabilization and activation of p53 target genes, and this was accompanied by repression of the ESC regulome beyond that normally observed with NIL only. Similarly, in PDX we observed increased repression of the ESC regulome in human CD34 + cells exposed to the combination of NIL plus MDM2i that included repression of HIF1alpha and a signature of genes required for cellular adaptations to hypoxia, and growth factor-mediated resistance to TKI therapy. Further, single cell analysis of differentiated human CD45 + cells from our PDX model, provided compelling evidence that acquisition of this repressive signature in the LSC, through combined NIL plus MDM2i treatment, re-wires them towards a basophilic fate, consistent with functional exhaustion of the LSC compartment.In conclusion, we have identified an ESC regulome in CML LSC and demonstrate that a combination of a TKI plus an MDM2i leads to p53 upregulation which antagonizes this regulome, providing a highly effective strategy to target near complete loss of functional LSC in pre-clinical models. Our study has revealed a new therapeutic paradigm to examine in other cancer stem cell populations that utilize ESC regulatory programs. DisclosuresHiggins: Roche/Genentech: Current Employment, Current equity holder in publicly-traded company. Copland: Astellas: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Incyte: Honoraria, Research Funding, Speakers Bureau; Cyclacel Ltd: Research Funding; Jazz: Honoraria, Speakers Bureau.

A Synthetic Lethal Approach to Eradicate AML Via Synergistic Activation of Pro-Apoptotic p53 By MDM2 and BET Inhibitors

Acute Myeloid Leukemia (AML) is a typically-lethal molecularly heterogeneous disease, with few broad-spectrum therapeutic targets. Unusually compared to many other cancers, over 90% of AML patients retain wild type TP53, encoding pro-apoptotic tumor suppressor p53. However, wild-type p53 functions are frequently suppressed by MDM2, an E3 ubiquitin ligase that targets p53 for proteasomal degradation. MDM2 inhibitors (MDM2i), which activate wild-type p53, show encouraging pre-clinical activity, but limited clinical activity. In an effort to find targets that synergize with p53 activation via MDM2i and minimize toxicity, we performed a cell-based synthetic lethal drug screen and a CRISPR viability screen. These screens identified BRD4 inhibition as a candidate synthetic lethal partner of MDM2i. BRD4 is a member of the Bromodomains and Extraterminal (BET) family of proteins, a transcriptional co-activator and already a candidate AML therapeutic target. Surprisingly, we found inhibition of BRD4 alone induces expression of some of p53 target genes. We unexpectedly reveal that BRD4 binds to p53 target genes and acts as a transcriptional repressor of these genes. Synergistic cell killing by the drug combination (MDM2i + BET inhibitor (BETi)) depends on synergistic activation of p53 target genes, such as PUMA and NOXA, due to simultaneous stabilization of p53 by MDM2i and relief of BRD4-mediated repression by BETi. Our combined therapy of MDM2i and BETi is synergistically lethal to human AML cell lines harboring wild type TP53in vitro, against two mouse models of AML in vivo, and against primary human patient blasts in vitro. Furthermore, we used BET PROTACs to selectively and completely induce degradation of BRD4 in cells. Consistent with results from BETi, BET degraders and MDM2i synergize to suppress cell viability with superior potency. Taken together, our data show BRD4 represses p53-mediated transcription activation and apoptosis in AML. Therefore, co-targeting wild-type TP53 and a transcriptional repressor function of BRD4 represent a novel synthetic lethal vulnerability in AML. Disclosures Latif: AbbVie: Consultancy, Honoraria; Takeda UK: Speakers Bureau; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Kite: Consultancy, Honoraria, Speakers Bureau; Jazz: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria. Higgins:Roche: Current Employment, Current equity holder in publicly-traded company, Other: Support of parent study and funding of editorial support. Copland:Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Cyclacel Ltd: Research Funding; Roche: Research Funding; Epizyme: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Astellas: Speakers Bureau; Gilead: Speakers Bureau.

An Oral Combination Study of Novel Nucleoside Analogue Sapacitabine and BCL2 Inhibitor Venetoclax to Treat Patients with Relapsed or Refractory AML or MDS

An Oral Combination Study of Novel Nucleoside Analogue Sapacitabine and BCL2 Inhibitor Venetoclax to Treat Patients with Relapsed or Refractory AML or MDS

A Phase I Study Combining CDK2/9 Inhibitor CYC065 with Venetoclax, a BCL2 Inhibitor, to Treat Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

Cyclin dependent kinases (CDKs) are critical for cell cycle regulation and transcriptional elongation. Dysregulated CDKs have been linked to the cancer hallmarks of uncontrolled proliferation and increased survival. CYC065 is a potent and orally‐available inhibitor of CDK2 and CDK9. CDK9 regulates transcription of genes through phosphorylation of RNA polymerase II (RNAP II) C-terminal domain (CTD). Through inhibition of CDK9, CYC065 suppresses CDK9-dependent gene expression and reduces the level of MCL1, a key anti-apoptotic protein. In the first-in-human study, CYC065 was administered by 4-hour infusion every 3 weeks in patients with advanced solid cancers. Biomarkers related to CYC065 target inhibition, e.g. phosphorylation of RNAP II CTD Ser2, a direct substrate of CDK9, and protein levels of downstream targets, such as MCL1, were determined in patient peripheral blood mononuclear cells (PBMCs). Durable MCL1 suppression was observed after a single dose in 11 out of 13 patients treated at the recommended phase 2 dose (RP2D) of 192 mg/m2. Five of these 13 patients achieved stable disease lasting ≥6 cycles (Do, KT et al, AACR Annual Meeting 2018 Abs CT037). Chronic lymphocytic leukemia (CLL) is a disease that depends upon the overexpression of anti-apoptotic proteins (MCL1, BCL2) for survival. Venetoclax, a BCL2 inhibitor, is one of the most active agents against CLL. However upregulation of MCL1 is associated with resistance to venetoclax (Oppermann S et al., Blood, 2016). Preclinical studies have demonstrated that CYC065 and venetoclax are synergistic in primary CLL cells, inducing apoptosis (Chen R et al, AACR Annual Meeting 2018 Abs 3905). This synergy may arise from targeting parallel anti-apoptotic mechanisms in the intrinsic apoptotic pathway that promote survival in CLL cells. The above findings support the conduct of an ongoing clinical study (NCT03739554) investigating a combination of CYC065 with venetoclax in CLL. CYC065 will be administered intravenously via 4-hour infusion on Day 1 and Day 15 in combination with daily venetoclax. One cycle is 28 days. Initial dose escalation is 33% and then 25% upon occurrence of the first dose limiting toxicity (DLT). RP2D is the highest dose level at which less than one-third of at least 6 patients experience a DLT during the first treatment cycle. Eligible patients are ≥18 years with CLL relapsed or refractory to standard treatment(s) including those with Richter transformation; adequate bone marrow, renal and liver functions are required. All patients will be asked to participate in the pharmacokinetic and pharmacodynamic studies. Plasma levels of CYC065 and its metabolites as well as venetoclax will be determined. PBMCs will be collected to assess MCL1 levels and phosphorylation and protein levels of other downstream targets of CDK9 inhibition. Treatment will continue until progression of disease, unacceptable toxicity or changes in patient condition that renders patients ineligible for further treatment. Laboratory tests and CT scans will be performed regularly to assess response according to standard criteria. Disclosures Wierda: Pharmacyclics LLC: Research Funding; AbbVie: Research Funding; GSK/Novartis: Research Funding; Gilead Sciences: Research Funding; KITE pharma: Research Funding; Sunesis: Research Funding; Genentech: Research Funding; Xencor: Research Funding; Janssen: Research Funding; Loxo Oncology Inc.: Research Funding; Cyclcel: Research Funding; Oncternal Therapeutics Inc.: Research Funding; Miragen: Research Funding; Juno Therapeutics: Research Funding; Acerta Pharma Inc: Research Funding. Chen:Cyclacel Ltd: Research Funding. Zheleva:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties. Blake:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties. Chiao:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties. Plunkett:Cyclacel Ltd: Research Funding.

Combining CDK2/9 Inhibitor CYC065 with Venetoclax, a BCL2 Inhibitor, to Treat Patients with Relapsed or Refractory AML or MDS

Cyclin dependent kinases (CDKs) are critical for cell cycle regulation and transcriptional elongation. Dysregulated CDKs have been linked to the cancer hallmarks of uncontrolled proliferation and increased survival. CYC065 is a potent and orally‐available inhibitor of CDK2 and CDK9. CDK9 regulates transcription of genes through phosphorylation of RNA polymerase II (RNAP II) C-terminal domain (CTD). Through inhibition of CDK9, CYC065 suppresses CDK9-dependent gene expression and reduces the level of MCL1, a key anti-apoptotic protein. In the first-in-human study, CYC065 was administered by 4-hour infusion every 3 weeks in patients with advanced cancers. Biomarkers related to CYC065 target inhibition, e.g. phosphorylation of RNAP II CTD Ser2, a direct substrate of CDK9, and protein levels of downstream targets, such as MCL1, were determined in patient's peripheral blood mononuclear cells (PBMCs). Durable MCL1 suppression was observed after a single dose in 11 out of 13 patients treated at the recommended phase 2 dose (RP2D) of 192 mg/m2. Five of these 13 patients achieved stable disease lasting ≥ 6 cycles (Do, KT et al, AACR Annual Meeting 2018 Abs CT037). Acute myeloid leukemia (AML) frequently relapses after initial treatment by intensive or low-intensive therapy. Drug resistance has been attributed to dysregulation in apoptotic pathways. AML cells often upregulate pro-survival members of the BCL2 family, such as BCL2 and MCL1, to avoid apoptosis (Grundy M et al, Oncotarget, 2018). Suppression of MCL1 triggered rapid apoptosis in AML, and cured AML-afflicted mice (Glaser SP et al, Genes Dev. 2012). Preclinically, CYC065 has demonstrated potent anti-tumor effect in various AML cell lines, including those with MLL rearrangements, and xenograft models (Frame S et al, AACR, 2010 Abs 3886; Frame S et al, SOHO, 2014 Abs 209). Venetoclax has modest single agent activity in AML. MCL1 dependence appeared to correlate with resistance to venetoclax (Konopleva M et al, Cancer Discovery, 2016). Preclinical study confirmed synergy of CYC065 and venetoclax, suggesting that the suppression of both BCL2 and MCL1 may be more beneficial than inhibiting either one alone (MacKay C et al. AACR-NCI-EORTC 2015 Abs B182). Based on the above rationale, a clinical study (NCT04017546) has been initiated to evaluate a combination of CYC065 with venetoclax in relapsed/refractory AML and MDS. CYC065 will be administered intravenously via 4-hour infusion on Day 1 and Day 15 in combination with daily venetoclax every 4 weeks. Initial dose escalation is 33% and then 25% upon occurrence of the first dose limiting toxicity (DLT). RP2D is the highest dose level at which less than one-third of at least 6 patients experience a DLT during the first treatment cycle. Eligible patients are ≥18 years with previously treated AML or MDS and ≥10% blasts in bone marrow or peripheral blood; adequate bone marrow, renal and liver functions are required. All patients will be asked to participate in the pharmacokinetic and pharmacodynamic studies. Plasma levels of CYC065 and its metabolites as well as venetoclax will be determined. PBMCs will be collected to assess MCL1 levels and the phosphorylation and protein levels of other downstream targets of CDK9 inhibition. Treatment will continue until progression of disease, unacceptable toxicity or changes in patient condition that renders patients ineligible for further treatment. Laboratory tests and bone marrow aspirate/biopsy will be performed to assess response according to standard criteria. Disclosures Borthakur: AbbVie: Research Funding; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; GSK: Research Funding; Polaris: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Incyte: Research Funding; Cyclacel: Research Funding; Janssen: Research Funding; Bayer Healthcare AG: Research Funding; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Oncoceutics, Inc.: Research Funding; Strategia Therapeutics: Research Funding; PTC Therapeutics: Consultancy; BMS: Research Funding; Oncoceutics: Research Funding; Eisai: Research Funding; NKarta: Consultancy; Xbiotech USA: Research Funding; Cantargia AB: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Eli Lilly and Co.: Research Funding; Agensys: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Arvinas: Research Funding. Kadia:BMS: Research Funding; Bioline RX: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Research Funding; Jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees. Al Azzawi:Cyclacel LTD: Research Funding. Zheleva:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties. Blake:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties. Chiao:Cyclacel Ltd: Employment, Equity Ownership, Patents &amp; Royalties.

Liposomal Cytarabine and Daunorubicin (CPX-351) in Combination with Gemtuzumab Ozogamicin (GO) in Relapsed Refractory (R/R) Patients with Acute Myeloid Leukemia (AML) and Post-Hypomethylating Agent (Post-HMA) Failure High-Risk Myelodysplastic Syndrome (HR-MDS)

Liposomal Cytarabine and Daunorubicin (CPX-351) in Combination with Gemtuzumab Ozogamicin (GO) in Relapsed Refractory (R/R) Patients with Acute Myeloid Leukemia (AML) and Post-Hypomethylating Agent (Post-HMA) Failure High-Risk Myelodysplastic Syndrome (HR-MDS)

Characteristics and Clinical Outcomes of Patients with Acute Lymphoblastic Leukemia with KMT2A (MLL) Rearrangement

Characteristics and Clinical Outcomes of Patients with Acute Lymphoblastic Leukemia with KMT2A (MLL) Rearrangement

Landmark Response and Survival Analyses from 206 AML Patients Treated with Guadecitabine in a Phase 2 Study Demonstrate the Importance of Adequate Treatment Duration to Maximize Response and Survival Benefit. Survival Benefit Not Restricted to Patients with Objective Response

Landmark Response and Survival Analyses from 206 AML Patients Treated with Guadecitabine in a Phase 2 Study Demonstrate the Importance of Adequate Treatment Duration to Maximize Response and Survival Benefit. Survival Benefit Not Restricted to Patients with Objective Response

Outcome of Patients (Pts) with Philadelphia Chromosome-Positive (Ph+) Acute Lymphoblastic Leukemia (ALL) without 3-Month Complete Molecular Response (CMR)

Outcome of Patients (Pts) with Philadelphia Chromosome-Positive (Ph+) Acute Lymphoblastic Leukemia (ALL) without 3-Month Complete Molecular Response (CMR)

Ten-Day Decitabine with Venetoclax (DEC10-VEN) in Acute Myeloid Leukemia: Updated Results of a Phase II Trial

Ten-Day Decitabine with Venetoclax (DEC10-VEN) in Acute Myeloid Leukemia: Updated Results of a Phase II Trial

Ultra-Accurate Assessment of Pretreatment ABL1 Kinase Domain (KD) Mutations in Patients (pts) with Newly Diagnosed Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ ALL) Using Duplex Sequencing (DS)

Ultra-Accurate Assessment of Pretreatment ABL1 Kinase Domain (KD) Mutations in Patients (pts) with Newly Diagnosed Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ ALL) Using Duplex Sequencing (DS)

Combined Ibrutinib and Venetoclax for First-Line Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

Combined Ibrutinib and Venetoclax for First-Line Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

Updated Results from the Phase II Study of Hyper-CVAD in Sequential Combination with Blinatumomab in Newly Diagnosed Adults with B-Cell Acute Lymphoblastic Leukemia (B-ALL)

Updated Results from the Phase II Study of Hyper-CVAD in Sequential Combination with Blinatumomab in Newly Diagnosed Adults with B-Cell Acute Lymphoblastic Leukemia (B-ALL)

Early Intervention with Hypomethylating Agents in Transfusion-Independent Patients with Myelodysplastic Syndrome

Early Intervention with Hypomethylating Agents in Transfusion-Independent Patients with Myelodysplastic Syndrome

Evolutionary Action (EA) Score of TP53 Mutations Defines Prognostic Subsets within TP53 Mutated Myelodysplastic Syndromes and Acute Myeloid Leukemia

Evolutionary Action (EA) Score of TP53 Mutations Defines Prognostic Subsets within TP53 Mutated Myelodysplastic Syndromes and Acute Myeloid Leukemia

Genomic Context and TP53 Allele Frequency Define Prognostic Subgroups and Response Outcomes in TP53 Mutated Myelodysplastic Syndromes

Genomic Context and TP53 Allele Frequency Define Prognostic Subgroups and Response Outcomes in TP53 Mutated Myelodysplastic Syndromes

Fludarabine, Cytarabine, G-CSF and Gemtuzumab Ozogamicin (FLAG-GO) Regimen Results in Better Molecular Response and Relapse-Free Survival in Core Binding Factor Acute Myeloid Leukemia Than FLAG and Idarubicin (FLAG-Ida)

Fludarabine, Cytarabine, G-CSF and Gemtuzumab Ozogamicin (FLAG-GO) Regimen Results in Better Molecular Response and Relapse-Free Survival in Core Binding Factor Acute Myeloid Leukemia Than FLAG and Idarubicin (FLAG-Ida)