Numerous public databases now collect and disseminate biological activity data from literature and patents, forming the basis for chemogenomics and novel scoring functions. However, data quality is often compromised due to multiple citations of values across different studies with varying protocols. To address this issue, we used the XGBoost model in combination with a BERT-based NLP approach and a distance-based out-of-distribution (OOD) data detection method to enhance classification accuracy and exclude review articles.

Vamotinib (PF-114) is a 3rd -generation, ATP-competitive oral tyrosine kinase inhibitor (TKI) active against wild-type and mutated BCR::ABL1 isoforms including BCR::ABL1T315I. We present final results of a phase-1 vamotinib dose-escalation study to identify maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) followed by expansion cohorts. 51 subjects with chronic myeloid leukaemia (CML) failing ≥ 1 2nd generation TKI or with BCR::ABL1T315I were enrolled. Subjects received vamotinib, 50–750 mg/d, continuously. Median exposure was 6 months (range, < 1–52 months). Median CML duration pre-study was 10 years (range, < 1–23 years). 27 subjects received ≥ 3 prior TKIs and 16 had BCR::ABL1T315I. The MTD was 600 mg with the Grade-3 psoriasis-like skin toxicity as the DLT. There were no vascular occlusive events nor deviations of ankle-brachial index. Complete haematologic response (CHR) was achieved in 14 of 30 subjects, major cytogenetic response (MCyR) in 14 of 44 subjects, complete cytogenetic response (CCyR) in 10 of 50 and major molecular response (MMR) in 7 of 51 subjects who did not have a CHR, MCyR, CCyR or MMR at enrollment. The best safety/efficacy dose was 300 mg with MCyR achieved in 6 of 7 subjects, CCyR in 5 of 9 and MMR in 4 of 9 subjects who did not have a MCyR, CCyR or MMR at enrollment. 5 of 16 subjects with BCR::ABL1T315I responded including 3 achieving a CHR, 3, a MCyR, and 1,a CCyR. 2 of 5 subjects failing ponatinib achieved a CHR. Vamotinib dose for further phase-3 study is 300 mg/d.

Bioisosteres are molecules that differ in substituents but still have very similar shapes. Bioisosteric replacements are ubiquitous in modern drug design, where they are used to alter metabolism, change bioavailability, or modify activity of the lead compound. Prediction of relative affinities of bioisosteres with computational methods is a long-standing task; however, the very shape closeness makes bioisosteric substitutions almost intractable for computational methods, which use standard force fields. Here, we design a quantum mechanical (QM)-cluster approach based on the GFN2-xTB semi-empirical quantum-chemical method and apply it to a set of H → F bioisosteric replacements. The proposed methodology enables advanced prediction of biological activity change upon bioisosteric substitution of -H with -F, with the standard deviation of 0.60 kcal/mol, surpassing the ChemPLP scoring function (0.83 kcal/mol), and making QM-based ΔΔG estimation comparable to ∼0.42 kcal/mol standard deviation of in vitro experiment. The speed of the method and lack of tunable parameters makes it affordable in current drug research.

The rational design of cyclin-dependent protein kinase (CDK) inhibitors presumes the development of approaches for accurate prediction of selectivity and the activity of small molecular weight anticancer drug candidates. Aiming at attenuation of general toxicity of low selectivity compounds, we herein explored the new chemotype of imidazole-4-N-acetamide substituted derivatives of the pan-CDK inhibitor PHA-793887. Newly synthesized compounds 1-4 containing an aliphatic methyl group or aromatic radicals at the periphery of the scaffold were analyzed for the prediction of relative free energies of binding to CDK1, -2, -5, and -9 using a protocol based on non-equilibrium (NEQ) thermodynamics. This methodology allows for the demonstration of a good correlation between the calculated parameters of interaction of 1-4 with individual targets and the values of inhibitory potencies in in vitro kinase assays. We provide evidence in support of NEQ thermodynamics as a time sparing, precise, and productive approach for generating chemical inhibitors of clinically relevant anticancer targets.

Background Many patients who recovered from COVID are still suffering from pulmonary dysfunction that can be persistent even for months after infection. Therefore, treatment to prevent irreversible impairment of lung function is needed. Treamid (bisamide derivative of dicarboxylic acid, BDDA) was shown to have anti-inflammatory and antifibrotic effects in animal models of pulmonary fibrosis. This study was designed to assess the safety, tolerability, and efficacy of Treamid in the rehabilitation of patients after COVID pneumonia. The aim was to establish whether Treamid could be effective in ameliorating post-COVID sequelae. Methods The phase 2, randomized, double-blind, placebo-controlled clinical trial was done at 8 medical centers in Russia. Patients with a diagnosis of COVID in the past medical history (with the first symptoms of COVID appear no earlier than 2 months before screening) and having fibrotic changes in the lungs, decreased lung function (percentage of predicted FVC and/or DLCO < 80%), and moderate or severe dyspnea according to mMRC scale were enrolled and randomly assigned in a 1:1 ratio (stratified by the initial degree of lung damage, age, and concomitant chronic diseases) by use of interactive responsive technology to peroral administration of Treamid 50 mg or placebo once a day for 4 weeks. The primary outcome was the proportion of patients who achieved clinically significant improvement in FVC and/or DLCO (defined as a relative increase in FVC of ≥ 10% or a relative increase in FVC in the range of ≥ 5 to < 10% plus a relative increase in DLCO of ≥ 15%) at week 4 compared with baseline. Secondary endpoints included changes from baseline in dyspnea scoring evaluated by the modified Borg and mMRC scales, pulmonary function (FEV 1 , FVC, FEV 1 /FVC ratio, DLCO, TLC, FRC), 6-min walk distance, the overall score of the KBILD questionnaire, and the proportion of patients with a reduction in the degree of lung damage assessed by CT scores. This trial was registered on ClinicalTrials.gov (Identifier: NCT04527354). The study was fully funded by PHARMENTERPRISES LLC. Results 12 out of 29 patients (41%) in Treamid group achieved clinically significant improvement in FVC and/or DLCO compared to 5 out of 30 patients (17%) in placebo group (p = 0.036). There was a significant decrease of dyspnea according to modified Borg scale observed in the Treamid group (− 0.9 ± 0.7 vs. − 0.4 ± 0.8, p = 0.018). No significant differences in the adverse events were noted. Exploratory analysis of the female population indicated superiority of Treamid over placebo by decreasing dyspnea and the extent of lung damage as well as increasing TLC. Conclusions 4 weeks oral administration of 50 mg Treamid was associated with clinically significant improvement in the post-COVID patients, evident by an increase in FVC and/or DLCO as well as decreasing dyspnea. Treamid was well tolerated and can be safely administered to patients discharged after COVID. Treamid was more effective in women visible by superior improvement of COVID sequalae after 4 weeks treatment. Considering that female gender is a risk factor associated with the development of post-COVID symptoms, Treamid might offer a pharmacological treatment for long-term sequalae after COVID and supports further investigation in future clinical trials in post-COVID patients.

Here we propose an over-the-hood docking method that compensates for systematic errors in the docking force fields. This method explicitly estimates the interaction energy of the ligand with the protein surface and uses it as a baseline to estimate the actual binding energy in the active site. It improves the accuracy of virtual screening in the LeadFinder package by up to 48%.

The pathophysiology of osteoarthritis (OA) includes the destruction of subchondral bone tissue and inflammation of the synovium. Thus, an effective disease-modifying treatment should act on both of these pathogenetic components. It is known that cSrc kinase is involved in bone and cartilage remodeling, and SYK kinase is associated with the inflammatory component. Thus the aim of this study was to characterize the mechanism of action and efficacy of a small molecule multikinase inhibitor MT-SYK-03 targeting SYK and cSrc kinases among others in different in vitro and in vivo arthritis models. The selectivity of MT-SYK-03 kinase inhibition was assayed on a panel of 341 kinases. The compound was evaluated in a set of in vitro models of OA and in vivo OA and RA models: surgically-induced arthritis (SIA), monosodium iodoacetate-induced arthritis (MIA), collagen-induced arthritis (CIA), adjuvant-induced arthritis (AIA). MT-SYK-03 inhibited cSrc and SYK with IC 50 of 14.2 and 23 nM respectively. Only five kinases were inhibited > 90% at 500 nM of MT-SYK-03. In in vitro OA models MT-SYK-03 reduced hypertrophic changes of chondrocytes, bone resorption, and inhibited SYK-mediated inflammatory signaling. MT-SYK-03 showed preferential distribution to joint and bone tissue (in rats) and revealed disease-modifying activity in vivo by halving the depth of cartilage erosion in rat SIA model, and increasing the pain threshold in rat MIA model. Chondroprotective and antiresorptive effects were shown in a monotherapy regime and in combination with methotrexate (MTX) in murine and rat CIA models; an immune-mediated inflammation in rat AIA model was decreased. The obtained preclinical data support inhibition of cSrc and SYK as a viable strategy for disease-modifying treatment of OA. A Phase 2 clinical study of MT-SYK-03 is to be started.

Since the beginning of the COVID-19 pandemic, clinical, radiological, and histopathological studies have provided evidence that organizing pneumonia is a possible consequence of the SARS-CoV2 infection. This post-COVID-19 organizing pneumonia (PCOP) causes persisting dyspnea, impaired pulmonary function, and produces radiological abnormalities for at least 5 weeks after onset of symptoms. While most patients with PCOP recover within a year after acute COVID-19, 5–25% of cases need specialized treatment. However, despite substantial resources allocated worldwide to finding a solution to this problem, there are no approved treatments for PCOP. Oral corticosteroids produce a therapeutic response in a majority of such PCOP patients, but their application is limited by the anticipated high-relapse frequency and the risk of severe adverse effects. Herein, we conduct a systematic comparison of the epidemiology, pathogenesis, and clinical presentation of the organizing pneumonias caused by COVID-19 as well as other viral infections. We also use the clinical efficacy of corticosteroids in other postinfection OPs (PIOPs) to predict the therapeutic response in the treatment of PCOP. Finally, we discuss the potential application of a candidate anti-inflammatory and antifibrotic therapy for the treatment of PCOP based on the analysis of the latest clinical trials data.

Background: Not everyone with CML responds optimally to TKI-therapy, especially those with BCR::ABL1T315I. PF-114 is a 4 th-generation oral tyrosine kinase-inhibitor (TKI) active against wild-type and mutated BCR::ABL1 isoforms including BCR::ABL1T315I. We present final results of a phase-1 study (NCT02885766).

At the end of 2019, a highly contagious infection began its ominous conquest of the world. It was soon discovered that the disease was caused by a novel coronavirus designated as SARS-CoV-2, and the disease was thus abbreviated to COVID-19 (COVID). The global medical community has directed its efforts not only to find effective therapies against the deadly pathogen but also to combat the concomitant complications. Two of the most common respiratory manifestations of COVID are a significant reduction in the diffusing capacity of the lungs (DLCO) and the associated pulmonary interstitial damage. One year after moderate COVID, the incidence rate of impaired DLCO and persistent lung damage still exceeds 30%, and one-third of the patients have severe DLCO impairment and fibrotic lung damage. The persistent respiratory complications may cause substantial population morbidity, long-term disability, and even death due to the lung fibrosis progression. The incidence of COVID-induced pulmonary fibrosis caused by COVID can be estimated based on a 15-year observational study of lung pathology after SARS. Most SARS patients with fibrotic lung damage recovered within the first year and then remained healthy; however, in 20% of the cases, significant fibrosis progression was found in 5–10 years. Based on these data, the incidence rate of post-COVID lung fibrosis can be estimated at 2–6% after moderate illness. What is worse, there are reasons to believe that fibrosis may become one of the major long-term complications of COVID, even in asymptomatic individuals. Currently, despite the best efforts of the global medical community, there are no treatments for COVID-induced pulmonary fibrosis. In this review, we analyze the latest data from ongoing clinical trials aimed at treating post-COVID lung fibrosis and analyze the rationale for the current drug candidates. We discuss the use of antifibrotic therapy for idiopathic pulmonary fibrosis, the IN01 vaccine, glucocorticosteroids as well as the stromal vascular fraction for the treatment and rehabilitation of patients with COVID-associated pulmonary damage.

The review summarizes the publications, available at the time it was written, addressing the chemical and biological processes that occur in the human body upon exposure to coronaviruses, in particular SARS-CoV-2. The mechanisms of viral particle entry into the cell, viral replication and impact on the immune system and on oxygen transport system are considered. The causes behind complications of the viral infection, such as vasculitis, thrombosis, cytokine storm and lung fibrosis, are discussed. The latest research in the field of small molecule medications to counteract the virus is surveyed. Molecular targets and possible vectors to exploit them are considered. The review is primarily written for specialists who want to understand the chains of activation, replication, action and inhibition of SARS-CoV-2. Due to the short period of such studies, the data on complexes of small molecule compounds with possible protein targets are not numerous, but they will be useful in the search and synthesis of new potentially effective drugs. The bibliography includes 144 references.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease characterized by interstitial fibrosis and progressive respiratory failure. Pirfenidone and nintedanib slow down but do not stop the progression of IPF. Thus, new compounds with high antifibrotic activity and simultaneously regenerative activity are an unmet clinical need. Recently, we showed that Treamid can help restoring the pancreas and testicular tissue in mice with metabolic disorders. We hypothesized that Treamid may be effective in antifibrotic therapy and regeneration of damaged lung tissue in pulmonary fibrosis. In this study, experiments were performed on male C57BL/6 mice with bleomycin-induced pulmonary fibrosis. We applied histological and immunohistochemical methods, ELISA, and assessed the expression of markers of endothelial and epithelial cells in primary cultures of CD31(+) and CD326(+) lung cells. Finally, we evaluated esterase activity and apoptosis of lung cells in vitro. Our data indicate that Treamid exhibits antifibrotic activity in mice with pulmonary fibrosis and has a positive effect on capillaries of the lungs. Treamid also increases the number of endothelial progenitor cells in the lungs of animals with pulmonary fibrosis. Lastly, Treamid increases esterase activity and decreases apoptosis of CD31(+) lung cells in vitro. Based on these findings, we suggest that Treamid may represent a promising compound for the development of new antifibrotic agents, which are capable of stimulating regeneration of lung endothelium in IPF patients.

Although CDK7 inhibitors are considered to be potential anticancer drugs, all inhibitors developed so far have significant disadvantages preventing their further use. We have developed a new CDK7 inhibitor scaffold lacking hepatotoxicity using molecular dynamics (MD) and free energy perturbation (FEP/MD) methods, and were able to double its binding affinity after additional research. The combination of MD and FEP/MD methods was shown to be a valuable instrument for the development of novel and potent CDK7 inhibitors for anticancer therapy.

The MDR1/P-glycoprotein (Pgp)/ABCB1 multidrug transporter is being investigated as a druggable target for antitumor therapy for decades. The natural product curcumin is known to provide an efficient scaffold for compounds capable of blocking Pgp mediated efflux and sensitization of multidrug resistant (MDR) cells to the Pgp transported drug doxorubicin (Dox). We performed molecular dynamics simulations and docking of curcumin derivatives into the Pgp model. Based on these calculations, a series of pyrazolocurcumin derivatives with predicted metabolic stability and/or improved binding affinity were proposed for synthesis and evaluation of MDR reversal potency against Dox selected K562/4 subline, a derivative of K562 human chronic myelogenous leukemia cell line. Compounds 16 and 19 which are both dimethylcurcumin pyrazole derivatives bearing an N-p-phenylcarboxylic amide substitution, were the most potent Pgp blockers as determined by intracellular Dox accumulation. Furthermore, at non-toxic submicromolar concentrations 16 and 19 dramatically sensitized K562/4 cells to Dox. Together with good water solubility of 16 and 19, these results indicate that the new pyrazolo derivatives of curcumin are a promising scaffold for development of clinically applicable Pgp antagonists.

The rapid development of new machine learning techniques led to significant progress in the area of computer-aided drug design. However, despite the enormous predictive power of new methods, they lack explainability and are often used as black boxes. The most important decisions in drug discovery are still made by human experts who rely on intuitions and simplified representation of the field. We used D3R Grand Challenge 4 to model contributions of human experts during the prediction of the structure of protein–ligand complexes, and prediction of binding affinities for series of ligands in the context of absence or abundance of experimental data. We demonstrated that human decisions have a series of biases: a tendency to focus on easily identifiable protein–ligand interactions such as hydrogen bonds, and neglect for a more distributed and complex electrostatic interactions and solvation effects. While these biases still allow human experts to compete with blind algorithms in some areas, the underutilization of the information leads to significantly worse performance in data-rich tasks such as binding affinity prediction.

Background: PF-114 is a 4th-generation oral tyrosine kinase-inhibitor (TKI) active against wild-type and mutated BCR-ABL1 isoforms including BCR-ABL1T315I. We present data from a phase-1 study in patients with chronic or accelerated phase chronic myeloid leukaemia (CML) failing ≥2 TKIs or with BCR-ABL1T315I (NCT02885766) with ≥6 months therapy. Methods: 3+3 dose-escalation study to determine maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary objectives included safety and efficacy based on haematological, cytogenetic, and molecular criteria. Adverse events (AEs) were graded using NCI-CTCAE v4.03. Results: 51 patients were enrolled. Daily doses were 50 mg (n=3), 100 mg (n=3), 200 mg (n=9), 300 mg (n=11), 400 mg (n=12), 500 mg (n=3), 600 mg (n=6), 750 mg (n=4) given continuously. Median age was 50 years (range, 29-82 years). Median CML duration pre-study was 10 years (range, 0.3-23 years). All patients had baseline ECOG performance scores 0-1. Twelve patients had BCR-ABL1T315I. Patients were heavily pre-treated: 25 received ≥3 prior TKIs; 5 patients with BCR-ABL1T315I received 1 prior TKI. Interim analysis was conducted at follow-up of ≥6 months (cut-off date January 16th 2019). Therapy was ongoing in 17 patients at doses 200 mg (n=4), 300 mg (n=9), 400 mg (n=3) and 600 mg (n=1) with median duration of exposure of 7,4 (range, 4,6-26), 9,2 (range, 7,4-26), 9,2 (range, 8,3-9,2) and 9,2 months. Other patients discontinued because of progression (n=18), adverse events (n=6), consent withdrawal (n=4), participation in another study (n=3) or other reasons (n=3). The MTD was 600 mg with the grade-3 psoriasis-like skin lesions the DLT, which occurred during the first 28 days of treatment. Reversible grade-3 skin toxicity occurred in 11 patients at doses ≥400 mg. There were no other drug-related non-hematologic grade-3 toxicities except 1 grade-3 toxic hepatitis at 400 mg and there were no detectable effects on ankle-brachial index or vascular occlusive events. The best safety/efficacy dose was 300 mg/d with 6 of 11 patients achieving a major cytogenetic response (MCyR) and 4 of them - a major molecular response (MMR). Higher doses were less effective probably because of toxicity-related therapy interruptions and discontinuations. Five of 12 patients with BCR-ABL1T315I responded, 3 of which achieved a complete hematologic response and 4 achieved MCyR. Conclusion: PF-114 was safe and effective in patients with CML failing ≥2 TKIs or with BCR-ABL1T315I. The most effective dose was 300 mg/d. Five of 12 patients with BCR-ABL1T315I responded. A pivotal study is beginning. Disclosures Turkina: Novartis: Consultancy, Speakers Bureau; Pfizer: Consultancy; Bristol Myers Squibb: Consultancy; fusion pharma: Consultancy; Novartis: Consultancy, Speakers Bureau. Vinogradova:Novartis: Consultancy; Fusion Pharma: Consultancy. Lomaia:Novartis: Other: Travel Grant;Lecture fee; Pfizer: Other: Travel Grant. Shukhov:Pfizer: Consultancy; Novartis: Consultancy. Chelysheva:Novartis: Consultancy, Honoraria; Fusion Pharma: Consultancy. Shikhbabaeva:Novartis: Consultancy; Fusion Pharma: Consultancy. Shuvaev:Fusion Pharma: Consultancy; Novartis: Consultancy; Pfize: Honoraria; BMS: Consultancy. Cortes:Pfizer: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Biopath Holdings: Consultancy, Honoraria; Immunogen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Astellas Pharma: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; BiolineRx: Consultancy; Sun Pharma: Research Funding; Merus: Consultancy, Honoraria, Research Funding; Forma Therapeutics: Consultancy, Honoraria, Research Funding. Baccarani:Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Takeda: Consultancy. Ottmann:Roche: Honoraria; Pfizer: Honoraria; Fusion Pharma: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Celgene: Honoraria, Research Funding; Incyte: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Mikhailov:Fusion Pharma: Employment. Novikov:Fusion Pharma: Employment. Shulgina:Fusion Pharma: Employment. Chilov:Fusion Pharma: Consultancy.

A t(9;22) chromosomal translocation which forms the chimeric tyrosine kinase breakpoint cluster region (BCR)‑Abelson murine leukemia viral oncogene homolog 1 (ABL) is a key mechanism underlying the pathogenesis of chronic myelogenous leukemia (CML). Pharmacological inhibition of BCR‑ABL with imatinib (Gleevec) has been reported as an effective targeted therapy; however, mutations (including the kinase domain of ABL) suppress the efficacy of inhibitors. PF‑114, a derivative of the third generation BCR‑ABL inhibitor ponatinib, demonstrated a high inhibitory activity against wild-type and mutant BCR‑ABL forms, such as the clinically important T315I. Furthermore, PF‑114 exhibited preferential kinase selectivity, safety, notable pharmacokinetic properties and therapeutic efficacy in a murine model. Investigation into the mechanisms of CML cell death revealed an exceptional potency of PF‑114 (at low nanomolar concentrations) for the CML‑derived K562 cell line, whereas leukemia cell lines that lack the chimeric tyrosine kinase were markedly more refractory. The molecular ordering of events mechanistically associated with K562 cell death included the dephosphorylation of CrkL adaptor protein followed by inhibition of ERK1/2 and Akt, G1 arrest, a decrease of phosphorylated Bcl‑2‑associated death promoter, Bcl‑2‑like protein 11, BH3 interacting‑domain death agonist, Bcl‑extra large and Bcl‑2 family apoptosis regulator, and reduced mitochondrial transmembrane potential. Increased Annexin V reactivity, activation of caspases and poly(ADP‑ribose)polymerase cleavage were proposed to lead to internucleosomal DNA fragmentation. Thus, PF‑114 may be a potent inducer of apoptosis in CML cells. Nevertheless, activation of STAT3 phosphorylation in response to PF‑114 may permit cell rescue; thus, a combination of BCR‑ABL and STAT3 inhibitors should be considered for improved therapeutic outcome. Collectively, the targeted killing of BCR‑ABL‑positive cells, along with other beneficial properties, such as in vivo characteristics, suggests PF‑114 as a potential candidate for analysis in clinical trials with CML patients.

Background: PF-114 mesylate is a 4th-generation oral tyrosine kinase-inhibitor (TKI) active against wild-type and mutated BCRABL1 isoforms including those with a BCRABL1T315I. We present data from a phase-1 study in subjects with chronic or accelerated phase chronic myeloid leukaemia (CML) failing ≥2 TKIs or who have BCRABL1T315I (NCT02885766). Methods: 3+3 dose-escalation design to determine maximum tolerated dose (MTD) followed by expanded cohorts for doses ≤MTD. The primary objective was to determine the MTD and identify dose-limiting toxicities (DLTs) during cycle 1 (28 days). Secondary objectives included safety and anti-CML activity based on hematological, cytogenetic, and molecular criteria. Adverse events (AEs) were assessed and graded using NCI-CTCAE v4.03. Results: 51 subjects were enrolled as of June 26, 2018. Daily doses were 50 mg (n=3), 100 mg (n=3), 200 mg (n=9), 300 mg (n=11), 400 mg (n=12), 500 mg (n=3), 600 mg (n=6), 750 mg (n=4) given on a continuous QD schedule. Median age was 50 years (range, 29-82 years). Median interval from diagnosis to study-entry was 10 years (range, 0-23 years). Subjects had baseline ECOG performance scores <2. 13 subjects were reported to have BCRABL1T315I. Subjects were heavily pre-treated: 25 had received ≥3 prior TKIs; 5 subjects with BCRABL1T315I received 1 prior TKI. 600 mg was identified as the MTD with 1 of 6 subjects experiencing a DLT at this dose (Gr 3 psoriasis-like skin lesion). Similar grade-3 skin lesions were also identified at the dose of 750 mg in 2 subjects and at 400 mg in 1 subject. Therapy is ongoing in 23 subjects at doses 200, 300 and 400 mg with median duration of exposure of 5 (range, 1-21), 3 (range, 1-12) and 4 (range, 1-19) cycles. Other subjects discontinued because of progression (n=16), AEs (n=6) or other reasons (n=6). The most common of non-hematologic toxicity was skin toxicity, which was common at doses of ≥400 mg. Grade-3 skin toxicity occurred in 3 subjects on daily dose 750 mg, 4 subjects on dose 600 mg, 1 patient on dose 500 mg and 3 subjects on dose 400 mg. Skin lesions resolved rapidly upon drug discontinuation and topical therapy. No other drug related non-hematologic grade-3 toxicities except a single case of grade-3 hepatitis on dose 400 mg were observed. No deterioration of ankle-brachial index or vascular occlusive events were observed. A complete hematologic response was achieved in 8 of 19 evaluable subjects including 3 of 8 with BCRABL1T315I. Major cytogenetic response was achieved in 6 of 21 evaluable subjects including 3 of 7 with BCRABL1T315I. Major molecular response was achieved in 2 of 18 subjects completing ≥13 cycles. Most cytogenetic and molecular responses were achieved at doses 200 and 300 mg which were well-tolerated and will be considered for the phase-2 study. Conclusion: MTD of PF-114 is 600 mg with skin toxicity as the DLT. The best safety/efficacy ratio was seen at doses of 200 and 300 mg which are being studied in expanded cohorts and soon in a phase-2 study. Turkina: Novartis: Other: provided consultations; Bristol Myers Squibb: Other: provided consultations; Phizer: Other: provided consultations; Fusion Pharma: Other: provided consultations. Shukhov:Novartis: Other: provided consultations and performed lectures ; Bristol Myers Squibb: Other: provided consultations and performed lectures . Chelysheva:Bristol Myers Squibb: Other: provided consultations and performed lectures; Fusion Pharma: Other: provided consultations ; Novartis: Other: provided consultations and performed lectures. Cortes:Daiichi Sankyo: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Arog: Research Funding. Ottmann:Novartis: Consultancy; Pfizer: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Celgene: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Fusion Pharma: Consultancy, Research Funding. Mikhailov:Fusion Pharma: Employment. Novikov:Fusion Pharma: Employment. Shulgina:Fusion Pharma: Employment. Chilov:Fusion Pharma: Employment.