Onconova Highlights Results from Phase 2 Trial of Oral Rigosertib In Combination with Azacitidine (Vidaza®) in Myelodysplastic Syndromes (MDS) at the 2018 ASH Annual Meeting

On December 3, 2018 Onconova Therapeutics, Inc. (NASDAQ:ONTX), a Phase 3 clinical-stage biopharmaceutical company focused on discovering and developing novel products to treat cancer, reported the presentation of the efficacy and safety results of oral rigosertib in combination with azacitidine (Vidaza) in patients with HR-MDS reported at an oral presentation during the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition in San Diego (Press release, Onconova, DEC 3, 2018, View Source [SID1234531818]). Rigosertib, the Company’s lead compound, is being evaluated in both intravenous and oral forms.

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ORAL PRESENTATION:

Phase 2 Expansion Study of Oral Rigosertib Combined with Azacitidine treatment in Patients with Higher-Risk (HR) Myelodysplastic Syndromes (MDS): Efficacy and Safety Results in HMA Treatment Naïve & Relapsed (Rel)/Refractory (Ref) Patients

Session Name: 637. Myelodysplastic Syndromes — Clinical Studies: Novel Therapeutics I

Date: Saturday, December 1, 2018

Presentation Time: 4:15 PM PST

Seventy-four (74) patients were treated with a median age of 69 years (range 42-90) at 9 clinical sites, and received either 840 mg or 1,120 mg of oral rigosertib daily divided into two doses, in combination with a standard dose of injectable azacitidine. Of the 55 evaluable patients, 29 patients were treated with a daily dose of 1,120 mg of oral rigosertib, either 560 mg twice daily (12 patients) or 840 mg in the a.m. and 280 mg in the afternoon (17 patients). Twenty-six patients were treated with 560 mg in the AM and 280 mg in the PM (daily dose of 840 mg) for the first three weeks of a four-week cycle. All patients also received 75 mg/m2/day SC or IV azacitidine during the second week of the four-week cycle. The median duration of treatment for the HMA naïve and HMA failed patients was 7.8 and 4.9 months respectively. The median duration of response in these groups was 12.2 and 10.8 months, respectively.

The overall response rate (ORR) using the IWG 2006 criteria, in 29 HMA naïve patients, was 90%; including 10 patients (34%) with Complete Remission (CR). Among the 26 evaluable HMA-

failed patients the ORR was 54% including 8% CR or PR. The median time to initial and best response were 1 and 4 cycles in the HMA naïve group and 2 and 5 cycles in the HMA failed group.

The safety population (n = 74) received at least 1 dose of oral rigosertib. The combination was well tolerated. Other than genitourinary adverse events (AEs), the AE profile was similar to those described for azacitidine alone in this patient population. Genitourinary AEs, including hematuria (45% incidence of all grades, including 9% grade 3, and dysuria (38% all grades and 9% grade 3) were observed. A Safety Optimization Strategy was implemented for the higher dose cohort of 1,120 mg of oral rigosertib. These strategies included earlier in the day administration of the PM dose, oral hydration, monitoring of urinary pH and mandatory bladder emptying at night. Collectively these strategies resulted in mitigation of the target genitourinary AEs, including reduction of genitourinary grade 3 AEs reported from an earlier cohort despite receiving a higher dose of oral rigosertib.

In conclusion, oral rigosertib in combination with azacitidine was well tolerated in HMA naïve and HMA failed HR-MDS patients. The combination produced an encouraging rate of overall response and complete remission in both groups. The safety optimization strategies and increased dose exploration of oral rigosertib in the combination is leading to the development of a pivotal Phase 3 trial in HMA and chemotherapy naïve patients.

Drs. Lewis Silverman and Guillermo Garcia Manero, the lead investigators of the study at Mount Sinai Medical Center and MD Anderson Cancer Center, respectively, commented, "This multi-institutional collaborative study based on earlier laboratory research showing synergistic activity of rigosertib in combination with azacitidine led to a clinical trial of this combination in higher-risk MDS patients for both HMA naive and failed patients. The high overall response rate reported today is impressive, as is the durability and rate of achieving complete remission. We are excited about progressing these studies to a randomized pivotal placebo-controlled Phase 3 trial. The overall tolerability of the combination and convenience of administration of oral rigosertib could be key advantages for these future studies."

Dr. Steve Fruchtman, President of Onconova Therapeutics, Inc, sponsor of this study and developer of rigosertib commented, "We are most grateful to the patients, their families and our dedicated collaborating investigators for their participation in this study. The impressive results presented here have led to our plan for a pivotal trial for these patients ultimately hoping to improve upon their current therapeutic options. Based on End of Phase 2 Meetings with the Health Authorities, we have developed a randomized controlled pivotal trial. We expect to start the regulatory process for the approval of this trial plan very shortly. We are hopeful that both intravenous and oral formulations of rigosertib will be useful in serving the needs of higher risk MDS patients".

This oral presentation was delivered by Shyamala Navada, MD, Mount Sinai Medical Center on Saturday, December 1, 2018.

A copy of the presentation is available by visiting the Scientific Presentations section of Onconova’s website.

Onconova plans to meet with the FDA to discuss the results of the Phase 2 trial and the planned Phase 3 trial, and to seek a Special Protocol Assessment. The Company has partnered rigosertib with SymBio Pharmaceuticals, for Japan and Korea, and with Pint Pharma for Latin American countries. Both partners have indicated their interest in participating in the proposed new pivotal Phase 3 trial by enrolling patients in their respective territories. SymBio is currently conducting Phase 1 studies with oral rigosertib in Japan and also participating in the Phase 3 global INSPIRE trial. The Company is also actively seeking additional collaborations for rigosertib in other geographies.

Oncolytics Biotech® Announces Increased PD-L1 Expression When Combining Pelareorep with a Proteasome Inhibitor in Poster Presentation at the 60th American Society of Hematology Annual Meeting & Exposition

On December 3, 2018 Oncolytics Biotech Inc. (NASDAQ: ONCY) (TSX: ONC), currently developing pelareorep, an intravenously delivered immuno-oncolytic virus, reported a poster presentation made at the American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting & Exposition taking place December 1-4 in San Diego, California (Press release, Oncolytics Biotech, DEC 3, 2018, View Source [SID1234531817]). The poster highlights pelareorep’s ability to increase PD-L1 expression on tumor cells in patients with relapsed myeloma.

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The poster, authored by Craig C. Hofmeister, Acting Associate Professor, Department of Hematology and Medical Oncology Emory University School of Medicine, et al., is titled "Oncolytics Virus Replication Using Pelareorep and Carfilzomib in Relapsed Myeloma Patients Increases PD-L1 Expression with Clinical Responses", was presented yesterday. This phase 1 study enrolled 15 patients with relapsed myeloma.

"There is a growing effort to identify agents that can upregulate PD-L1 to increase the potential number of patients that can be treated with immune checkpoint blockade," said Dr. Hofmeister. "The data in this poster clearly demonstrate an increase in viral infection and viral replication, as well as pelareorep-dependent PD-L1 increased expression on the surface of myeloma cells, among patients undergoing treatment with pelareorep in combination with carfilzomib."

Highlights from the Poster:

Responses include:

Three very good partial responses (at least 90% reduction in monoclonal protein)

Three partial remissions (at least 50% reduction in monoclonal protein)

Three minimal responses (between 25% and 50% response to a drug or regimen in a clinical trial

Three stable disease

In patients receiving pelareorep with a clinical response, there was simultaneous CD8, PD-L1, and NK cell response, as well as activated caspase-3 expression

In patients treated with pelareorep, PD-L1 expression increased significantly more in patients with clinical response

"This presentation adds to the growing body of clinical evidence that pelareorep can boost PD-L1 expression and has the potential to be a backbone for immune checkpoint inhibition," said Dr. Matt Coffey, President and Chief Executive Officer of Oncolytics Biotech. "We appreciate the continued support of Dr. Hofmeister and look forward to collecting additional data from his subsequent study combining pelareorep with Bristol Myers Squibb’s immune checkpoint inhibitor, Opdivo, which should begin enrollment before the end of the year."

The poster can be found at View Source

About Pelareorep

Pelareorep is a non-pathogenic, proprietary isolate of the unmodified reovirus: a first-in-class intravenously delivered immuno-oncolytic virus for the treatment of solid tumors and hematological malignancies. The compound induces selective tumor lysis and promotes an inflamed tumor phenotype through innate and adaptive immune responses to treat a variety of cancers and has been demonstrated to be able to escape neutralizing antibodies found in patients.

argenx Provides Detailed Data from Phase 2 Clinical Trial of Efgartigimod in Immune Thrombocytopenia and Phase 1/2 Clinical Trial of Cusatuzumab in Acute Myeloid Leukemia

On December 3, 2018 argenx (Euronext & Nasdaq: ARGX), a clinical-stage biotechnology company developing a deep pipeline of differentiated antibody-based therapies for the treatment of severe autoimmune diseases and cancer, reported that it will share the detailed data from its Phase 2 clinical trial of efgartigimod (ARGX-113) in immune thrombocytopenia (ITP) and the Phase 1 portion of its Phase 1/2 clinical trial of cusatuzumab (ARGX-110) in acute myeloid leukemia (AML) and high-risk myelodysplastic syndromes (MDS) during a workshop being held in conjunction with the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition (Press release, argenx, DEC 3, 2018, View Source [SID1234531816]).

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The workshop is being held on Monday, December 3, 2018 at 12:00 p.m. PT. A live webcast of the workshop will be available on argenx’s website at www.argenx.com. A replay of the webcast will be available for 90 days following the presentation.

"These datasets highlight the power of the collaborations we’ve forged with leading academic institutions. As part of these collaborations, we combine our antibody discovery capabilities with our collaborators’ deep disease biology insights to together unravel the functions of novel targets. We have built our broad pipeline in this way and have demonstrated strong execution with each new product candidate we bring forward. Based on the clinically meaningful results and clean tolerability profiles we have observed to date, we believe we have two antibody molecules with efgartigimod and cusatuzumab that are both first-in-class and potentially best-in-class," commented Tim Van Hauwermeiren, Chief Executive Officer of argenx.

"We established strong proof-of-concept with efgartigimod in a second autoimmune indication showing a clear correlation between IgG reductions, platelet count increases and reduced bleeding events. The improvements in platelet counts were clinically meaningful in the treatment arms after a short drug exposure in a truly refractory ITP patient population. With these results and the drug candidate’s continued favorable tolerability, we look forward to advancing into a potential pivotal trial next year," commented Nicolas Leupin, Chief Medical Officer of argenx.

Key ITP Clinical Results

This trial evaluated 38 adult patients with primary ITP who were inadequately controlled on standard of care (platelet count < 30 x109/L at screening) in a Phase 2 proof-of-concept trial of efgartigimod. Patients received 4 doses over 3 weeks of either 5 mg/kg or 10 mg/kg of intravenous (IV) efgartigimod, or placebo. The Phase 2 trial was amended in December 2017 to extend the patient follow-up period to 21 weeks and to include the option to enter an open-label extension (OLE) trial. Data being presented today are the full data set.

The primary endpoint was safety and tolerability; efgartigimod was well-tolerated in all patients, with most adverse events (AEs) characterized as mild and deemed unrelated to trial drug.

Clinically meaningful improvements in platelet counts were seen across ITP classifications and standard of care and included:

·

46% of patients improved platelet count to > 50×109/L during two or more visits in each of the 5 mg/kg and 10 mg/kg dosing cohorts compared to 25% in the placebo cohort.

·

Updated data show that 67% of patients in the OLE trial improved platelet count to > 50×109/L during two or more visits following the first dosing cycle. Responders from the 10 mg/kg arm in the primary trial all responded again upon retreatment in the OLE trial.

·

Onset of platelet count reaching 50×109/L for the first time ranged from week 1 to week 10, consistent with disease heterogeneity.

·

For efgartigimod-treated patients with clinically meaningful platelet responses (> 50×109/L during two or more visits), the mean duration of platelet response was 40 days versus 16 days for placebo treated patients, with responses lasting the trial duration.

38% of efgartigimod-treated patients showed durable platelet count improvements to clinically meaningful and statistically significant levels of > 50×109/L for at least 10 cumulative days, compared to 0% of placebo patients (p=0.03).

Lasting IgG reductions consistent with levels achieved in previous studies (updated results) included:

All efgartigimod-treated patients showed a rapid and deep reduction of total IgG levels, consistent with the pharmacodynamic effects observed in previous clinical trials. Reduction of IgG levels was consistent across IgG subtypes.

·

Reduction in platelet-associated autoantibodies observed in the majority of patients with clinically meaningful platelet increase.

·

Low titer of anti-drug antibodies was detected in 16.7% of placebo patients and 30.8% of treated patients in the 10 mg/kg arm with no apparent effect on pharmacokinetics or pharmacodynamics.

Bleeding events were assessed using three metrics—adverse event reporting, the WHO scale and the ITP-BAT scale—and showed that efgartigimod reduced bleeding events (updated results) across each scale including:

AE reporting showed no severe bleeding events in any patient, mild bleeding events only were reported in the 10 mg/kg arm and mild and moderate in the 5 mg/kg and placebo arm.

·

Incidence of bleeding events was reduced by efgartigimod treatment as assessed by the WHO bleeding scale, with separation from placebo as early as the third dose in the 10 mg/kg arm.

·

Incidence of bleeding events in the skin was reduced by efgartigimod treatment as assessed by the ITP-BAT bleeding scale, with no clear signal of bleeding events in the mucosa or organs in either treatment arm.

·

Efgartigimod treatment resulted in clear correlation between IgG reduction, platelet count improvement and bleeding event reduction.

Based on these data, argenx plans to advance efgartigimod (IV) to Phase 3 development in ITP. argenx also expects to initiate a Phase 2 trial in ITP using a subcutaneous formulation of efgartigimod.

Key AML Clinical Results

argenx evaluated 12 newly diagnosed AML patients unfit for intensive chemotherapy in the Phase 1 dose escalation part of the open-label Phase 1/2 clinical trial. Patients received cusatuzumab in combination with Vidaza. Data being presented today are updated as of the new cut-off date of October 15, 2018.

Cusatuzumab continued to be well-tolerated in AML patients on all four doses (1 mg/kg, 3 mg/kg, 10 mg/kg, 20 mg/kg).

·

The data show an overall response rate (ORR) across the 12 patients of 92% (11/12 patients), including 10 patients (91%) with a complete remission with or without hematologic recovery (CR/CRi) and 1 (9%) partial remission (PR).

Responses were seen in patients across age and risk category, including IDH2 and TP53 mutations.

The median duration on trial as of data cut-off was 8.1 months, ranging from 2 to 17.4 months, with 6 patients still on trial.

Five patients (42%) achieved minimal residual disease (MRD) negativity as measured by flow cytometry and molecular genetics in the bone marrow.

Translational data demonstrated that cusatuzumab monotherapy and in combination with Vidaza significantly reduced leukemic stem cells in the bone marrow of AML patients.

argenx is currently enrolling an initial 21 AML patients in the Phase 2 part of its Phase 1/2 clinical trial using the 10 mg/kg dose of cusatuzumab.

"We continue to be excited by the encouraging dataset from our Phase 1/2 trial of cusatuzumab in AML and MDS. This agent targets the CD70/CD27 pathway which has the potential to be a novel and selective mechanism in treating newly diagnosed AML patents regardless of age or cytogenetic profile. Today we are seeing a growing depth of responses from patients on cusatuzumab, with 10 out of 12 patients reaching complete response and 8 of these 10 with hematologic recovery, which patients tolerated well. Six patients remain on trial, and we will watch as these data mature, including the durability of responses," added Nicolas Leupin, Chief Medical Officer of argenx.

About Efgartigimod

Efgartigimod (ARGX-113) is an investigational therapy for IgG-mediated autoimmune diseases and was designed to exploit the natural interaction between IgG antibodies and the recycling receptor FcRn. Efgartigimod is the Fc-portion of an IgG1 antibody that has been modified by the argenx proprietary ABDEG technology to increase its affinity for FcRn beyond that of normal IgG antibodies. As a result, efgartigimod blocks antibody recycling through FcRn binding and leads to fast depletion of the autoimmune disease-causing IgG autoantibodies. The development work on efgartigimod is conducted in close collaboration with Prof. E. Sally Ward (University of Texas Southwestern Medical and Texas A&M University Health Science Center, a part of Texas A&M University (TAMHSC)).

About Cusatuzumab

Cusatuzumab (ARGX-110) is an investigational SIMPLE Antibody targeting CD70, an immune checkpoint target involved in hematological malignancies, several solid tumors and severe autoimmune diseases. Cusatuzumab is designed to: block CD70, kill cancer cells expressing CD70 through complement dependent cytotoxicity, enhanced antibody-dependent cell-mediated phagocytosis and enhanced antibody-dependent cell-mediated cytotoxicity, and restore immune surveillance against solid tumors (Silence K. et al. mAbs 2014; 6 (2):523-532). Cusatuzumab is currently being evaluated in patients with hematological malignancies, including a Phase 1/2 trial in combination with Vidaza in patients with newly diagnosed acute myeloid leukemia and high-risk myelodysplastic syndromes and the Phase 2 part of a Phase 1/2 trial in patients with relapsed/refractory cutaneous T-cell lymphoma (CTCL). Preclinical work on cusatuzumab in AML was performed in collaboration with the Tumor Immunology Lab of Prof. A. F. Ochsenbein at the University of Bern, who won, together with Prof. Manz at the University Hospital of Zürich, the prestigious 2016 Otto Naegeli Prize for his breakthrough research on CD70/CD27 signaling with therapeutic potential for cancer patients.

Sunesis Pharmaceuticals Announces Presentation of Preliminary Data from Phase 1b/2 Trial of Vecabrutinib in Patients with CLL and Other B-Cell Malignancies at ASH Annual Meeting

On December 2, 2018 Sunesis Pharmaceuticals, Inc. (Nasdaq:SNSS) reported the presentation of results from the Company’s Phase 1b/2 clinical trial of its non-covalent BTK inhibitor vecabrutinib in adults with relapsed/refractory chronic lymphocytic leukemia (CLL) and other B-cell malignancies (Press release, Sunesis, DEC 3, 2018, View Source [SID1234531815]). The results will be presented today, December 2, from 6:00-8:00 p.m. PT in a poster session titled "CLL: Therapy, excluding Transplantation: Poster II" at the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting in San Diego, California. The poster, titled "Preliminary Safety, Pharmacokinetic, and Pharmacodynamic Results from a Phase 1b/2 Dose-Escalation and Cohort-Expansion Study of the Noncovalent, Reversible Bruton’s Tyrosine Kinase Inhibitor, Vecabrutinib, in B-Lymphoid Malignancy Patients with Prior BTKi Therapy," Abstract No. 3141, is available at www.sunesis.com.

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"To date, vecabrutinib has demonstrated both an encouraging safety profile and evidence of pharmacodynamic activity in CLL and other B cell cancer patients both with and without the BTK C481 mutation," said Dayton Misfeldt, Sunesis interim Chief Executive Officer. "We believe vecabrutinib has significant potential to be an important new treatment for ibrutinib-resistant B-cell malignancy patients, and its additional activity as an ITK inhibitor suggests further directions for clinical investigation. We look forward to continuing the dose escalation, as we believe that the target dose level is likely to be between 100 mg and 300 mg BID. We are excited to be working with such thoughtful and diligent investigators at eight premier sites across the U.S., and we thank our investigators for their continued support."

Data reported today were available from 11 of 13 treated patients. These included 7 with relapsed/refractory CLL, two with mantle cell lymphoma (MCL), and two with Waldenstrom macroglobulinemia (WM). Patients had received an average of 5 lines of prior therapy, and all had progressed on prior covalent BTK inhibitor treatment. Four of the 7 CLL patients had BTK C481 mutations. Currently, 4 patients are on study: one in Cycle 2, one in Cycle 3, and two new subjects who are in Cycle 1 and are anticipated to complete the 50 mg cohort.

The poster builds vecabrutinib’s profile in three key areas:

Safety: data on treatment-emergent adverse events (TEAEs) were available for 10 patients. The most common TEAEs of any grade were anemia (70%) and neutropenia and night sweats (50% each). Grade 3 drug-related AEs were anemia, neutropenia,

leukocytosis, and ALT increase (10% each). In the second cohort, one patient experienced a dose-limiting toxicity of an inadequate number of Cycle 1 doses administered due to a drug-related grade 3 ALT elevation, resulting in expansion of the cohort to 6 patients.

Pharmacokinetics: the pharmacokinetic profile of the 50mg dose is approximately dose proportional to the 25 mg dose. The next dose levels are expected to produce plasma concentrations associated with consistently high inhibition of BTK.

Pharmacodynamics: vecabrutinib inhibition of BTK phosphorylation was rapid and sustained in the 5 patients who had adequate baseline signal for analysis. Decreases in serum concentrations of key cytokines associated with B-cell malignancies, CCL2, CCL3, and CCL4, were also observed in 7 patients, consistent with inhibition of BTK signaling.

Webcast Information

The data will be further discussed as part of an analyst and investor event being held in San Diego today, December 2, at 8:00 p.m. PT, with the slide webcast commencing at 8:30 p.m. PT. The event is intended for institutional investors and sell-side analysts only. Please contact [email protected] for more information. The live webcast of the event, with slides, will be available to all on the Investors section of the Sunesis website at www.sunesis.com and will be archived for 90 days.

About Vecabrutinib

Vecabrutinib (SNS-062) is a selective, oral, reversible, non-covalent inhibitor of Bruton’s tyrosine kinase (BTK). BTK is a validated target for the treatment of B-cell malignancies driven by B-cell receptor signaling. Vecabrutinib retains its activity in the presence of a BTK C481S mutation, the most common mutation seen in ibrutinib-resistant CLL patients. In preclinical studies, vecabrutinib demonstrated potent activity in both wild-type and C481S-mutant BTK. Vecabrutinib has also been shown to inhibit a select number of other kinases including IL2-inducible T-cell kinase (ITK), which may improve T cell function. In a Phase 1a randomized, double-blind, placebo-controlled single ascending dose study in healthy volunteers, vecabrutinib demonstrated improved pharmacokinetics over ibrutinib, and sustained inhibition of BTK. Vecabrutinib is now being investigated in a Phase 1b/2 study in patients with relapsed CLL and other B-cell malignancies.

OHSU and Aptose Present New CG-806 Preclinical Data at ASH 60th Annual Meeting

On December 3, 2018 Oregon Health & Science University (OHSU) and Aptose Biosciences Inc. (NASDAQ: APTO, TSX: APS) reported the presentation of preclinical data demonstrating that CG-806, a first-in-class pan-FLT3/pan-BTK inhibitor, exhibits broad ex vivo potency on bone marrow cells from patients with diverse hematologic malignancies and superior potency relative to ibrutinib on those bone marrow cells from patients with CLL or other B-cell cancers (Press release, Aptose Biosciences, DEC 3, 2018, View Source [SID1234531814]). In addition, bioinformatic analyses revealed an unexpected ex vivo potency of CG-806 on bone marrow cells from AML patients with IDH1 mutations or with FLT3-ITD mutations. Plus, CG-806 demonstrated a favorable safety profile in GLP toxicology and safety studies. The data were highlighted in a poster presentation on Sunday, December 2, 2018 at the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition being held December 1-4, 2018 in San Diego, CA. Separately, Aptose and The University of Texas MD Anderson Cancer Center researchers also presented new data on CG-806 at ASH (Free ASH Whitepaper) (see press release here).

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Studies have shown that more than 50% of patients with CLL and mantle cell lymphoma (MCL) discontinue ibrutinib treatment due to intolerance or emergence of resistant disease. "Our data indicate that CG-806 clearly addresses ibrutinib’s shortcomings, inhibiting driver and rescue pathways to directly and potently kill a broad range of malignant B-cells. CG-806 has potential to be an important part of our future armamentarium against hematologic malignancies that are resistant, refractory or intolerant to other therapies," said Jeffrey W. Tyner, Ph.D., Associate Professor in the OHSU School of Medicine department of Cell, Developmental & Cancer Biology.

The poster, CG-806, a First-in-Class Pan-FLT3/Pan-BTK Inhibitor, Exhibits Broader and Greater Potency than Ibrutinib Against Primary and Cultured Malignant B Cells, evaluated the activity of CG-806 on various hematologic malignancy cell lines and patient primary bone marrow specimens. CG-806 inhibited cell proliferation and induced apoptosis with a potency that was 50-6,000 times greater than that of ibrutinib when tested against 14 established malignant B-cell lines in vitro. When tested against 124 samples freshly isolated from the bone marrow of chronic lymphocytic leukemia (CLL) patients, the median IC50 for CG-806 was 0.11 µM and the median for ibrutinib was 4.09 µM, respectively, p<0.001. Since stromal mediated signaling plays an important role in malignant B-cell survival and chemoresistance, the apoptotic effect of CG-806 was further analyzed on cultured and primary malignant B-cells in the presence of stromal cells, and its potency was not impaired. CG-806 was shown to be significantly more potent than Ibrutinib at inhibiting malignant B-cell colony formation, migration, and inducing apoptosis in the presence of stromal cells.

Primary cells from patients with diverse hematologic malignancies are highly sensitive to CG-806, including cells with the FLT3-ITD mutation, found in approximately 30% of acute myeloid leukemia (AML) patients. The data presented at ASH (Free ASH Whitepaper) showed that primary cells from AML patients with the IDH-1 mutation similarly demonstrated high sensitivity to CG-806. Aptose also reported new results from the 28-day GLP toxicity and toxicokinetic studies of CG-806, which continue to demonstrate a highly favorable safety profile with no adverse findings to date.

"CG-806’s activity against IDH-1 mutant AML patient bone marrow cells is an unexpected new finding that further broadens its potential use and potential paths for rapid development," said William G. Rice, Ph.D., Chairman and Chief Executive Officer of Aptose. "In addition, CG-806 has continued to perform well in all toxicology and safety studies, and we look forward to filing an IND in early 2019."

About CG-806
CG-806 is a preclinical stage oral, first-in-class pan-FLT3/pan-BTK multi-cluster kinase inhibitor. This small molecule demonstrates potent inhibition of wild type and all mutant forms of FLT3 (including internal tandem duplication, or ITD, and mutations of the receptor tyrosine kinase domain and gatekeeper region), eliminates acute myeloid leukemia (AML) tumors in the absence of toxicity in murine xenograft models, and represents a potential best-in-class therapeutic for patients with AML. Likewise, CG-806 demonstrates potent, non-covalent inhibition of the wild type and Cys481Ser mutant forms of the BTK enzyme, as well as other oncogenic kinase pathways operative in B cell malignancies, suggesting CG-806 may be developed for various B-cell malignancy patients (including CLL, MCL, DLBCL and others) that are resistant/refractory/intolerant to covalent BTK inhibitors. It is in development for acute myeloid leukemia (AML) and B cell lymphoma.