T315i mutation was present in 100% of the clones from the preponatinib sample and. Combination of hypercvad with ponatinib as firstline. Ponatinib ap24534 is currently the only approved cml drug that is active against the abl1t315i mutation. Sep 29, 2015 about half of losses in response are characterised by point mutation within the abl kinase domain. Mutations of bcrabl1 are observed in 50% of patients with imatinibresistant chronic myeloid leukemia cml. The t315i mutation is one of the most resistant mutation in vitro. Mutations of the bcrabl1 fusion gene represent a well established cause of resistance to tyrosine kinase inhibitors.
The prevalence of the t315i mutation was found to be 7% 460. It might represent a treatment option for patients with this mutation and complement the current clinically. Optimizing kinase inhibitor selection for cml patients. Mar 16, 2016 allogeneic stem cell transplantation sct is currently the only curative treatment option for chronic myeloid leukemia cml patients with bcrabl t315i mutations. T315i mutation of bcrabl1 into human philadelphia chromosomepositive leukemia cell lines by homologous recombination using the crisprcas9 system.
Despite the remarkable success of imatinib against bcrabl, development of secondary resistance, most often due to point mutations in the bcrabl tyrosine kinase tk domain, is quite common. T315i mutation of bcrabl1 into human philadelphia chromosome. T315i is one of the most common acquired mutations in this domain, which occurs in atp binding site and inhibits the formation of hydrogen bond with im. A simple and sensitive method is thus required to detect t315i mutation at the earliest stage. Bcrabl t315i, a mutant resistant to all approved abl kinase inhibitors, is emerging as a common pathway of failure on all three inhibitors. F311l, m351t, and t315i and all patients with preexisting bcrabl mutations exhibited imatinib resistance 33. Next generation sequencing of hematologic neoplasms. Abl1 fusion protein, such as abl1t315i, typically emerge after prolonged kinase inhibitor treatment. Strategies to circumvent the t315i gatekeeper mutation in. Ponatinib may soon be available for these patients.
All of the bcrabl mutants are inhibited by the 2nd generation inhibitors with the exception of the t315i mutant. The side chain of ile315 is accommodated in the abl t315i mutant structure without large conformational changes proximal to the site of mutation. Ponatinib avoids the steric hindrance imposed by the threonine. Detection of t315i using digital polymerase chain reaction in. A couple of imatinibresistant sublines with t315i mutation were established after longterm. The first results of this ongoing trial indicate that the combination of chemotherapy with ponatinib is effective in achieving early sustained remissions in patients with newly diagnosed philadelphia chromosomepositive acute lymphoblastic leukaemia. A personalised medicine approach for ponatinibresistant. If your cml stops responding to treatment with a tki, another one may be tried. Hu and the cdk4cdk6blocker palbociclib inhibit growth of cml clones expressing bcrabl1t315i or complex t315iincluding compoundmutations. The t315i mutant form of bcrabl lacks a threonine residue, which provides a. Some forms of cml, those that have the t315i mutation, are resistant to current. More than 90% of cml cases are caused by a chromosomal abnormality that results in the formation of a socalled philadelphia chromosome. Bui a victoria hodson b tom king b derek leopold a shaodong dai a valerie fiolkoski b sarah oakes b richard duke b david apelian b alex franzusoff b james degregori a.
The initial amino acid conformations of the peptides were manually adjusted to avoid clashes. I agree with this recommendation, he said, noting that patients with a t315i mutation have a lack of response to secondgeneration tkis. The t315i mutation accounts for 10% to 20% of all mutants detected after failure on tki therapy. The bcrabl mutation, t315i, is a common mutation and is resistant to both imatinib and secondgeneration abl kinase inhibitors. All four patients with mutation were in advance phases and had previously lost all their responses.
The standard treatment for chronic phase cml is a tyrosine kinase inhibitor tki like imatinib gleevec, nilotinib tasigna. In patients with cmlcp, several studies showed that patients with t315i have a shorter survival. Genomic mutation identifier cosv to indicate the definitive position of the variant on the genome. M244v, g250e, y253fh, e255kv, t315i, m351t, and f359v. Bcrabl tyrosinekinase inhibitors tki are the firstline therapy for most patients with chronic myelogenous leukemia cml. The drug is a bit unique in that it is given intravenously at this time. Although imatinib is effective in chronic myeloid leukemia treatment, imatinib resistance due to the t315i mutation andor other mutations is a. Characteristics of patients are shown in table 1, table 2. Strategies to circumvent the t315i gatekeeper mutation in the. We assessed the prognostic value of small clones with the t315i mutation at specific time points using the novel technology digital polymerase chain reaction pcr, which is more sensitive than direct sequencing. It is caused by a single cytosine to thymine c t base pair substitution at position 944 of the abl gene codon 315 of the abl protein sequence resulting in amino acid threonine being substituted by isoleucine at that.
T315i is one of the most common acquired mutations in. Mutation t315i expression system mammalian amino acid startstop s229k512. Acquired mutations in tyrosine kinase domain of bcrabl protein are a mechanism for development of resistance. Ap24534 is an orally active multitargeted kinase inhibitor that potently inhibits bcrabl t315i.
Hyperdiploidy associated with t315i mutation in bcrabl. The durable clearance of the t315i bcrabl mutated clone. At the time the mutation was detected, 8 patients were in the chronic phase cp, 7 in the accelerated phase. Evaluation of t315i mutation frequency in chronic myeloid.
However, about 20 % of cml patients harbor primary or acquired resistance to tyrosine kinase inhibitors. We report the case of a 57yearold man diagnosed with cml in 2003 in whom imatinib therapy failed after which he acquired the t315i mutation. Treating t315ipositive chronic myeloid leukemia cml. Jun 30, 2017 the records of 184 leukemia patients with the t315i mutation were analyzed. Furthermore, the t315i mutation induces a conformational change in several amino acid residues, which are important for the binding of imatinib and bcrabl the allosteric effect. The first patient was started on the drug in november of 2005. Detection of t315i using digital polymerase chain reaction. In this study, we present the crystal structure of the kinase domain of the c. The mutant residues i315 and l317 are depicted as red and yellow sticks, respectively. Deregulated activity of bcrabl1, a nonreceptor tyrosine kinase encoded by the fusion gene resulting from the t9.
The aim of this study was to evaluate the prevalence of this mutation in bcrablpositive cml and all patients. This paper compared ponatinib iclusib and stem cell transplantation in leukemia patients with an abnormality on the t315i gene. The most relevant bcrabl mutation results from the replacement of threonine by isoleucine at abl amino acid position 315, referred to as the t315i mutation. Crystal structure of the t315i mutant of abl kinase zhou. Of 449 patients enrolled in pace from september 2010 to october 2011. The bcrablt315i mutation confers drug resistance to. Pna clamping pcr, bcrabl, t315i, imatinib, sequencing, chronic myeloid. T315if359c compound mutations supplementary table s2, available at. Bcrabl point mutations and tki treatment in cml patients. Cml, imatinib resistance, t315i mutation, f317 lmutation, allele specific oligonucleotidespcr.
Molecular diagnostics lab t315i bcrabl mutation analysis. Effective treatment options for patients with chronic myeloid leukemia cml or philadelphia. Novel therapies for t315i mutant chronic myeloid leukemia january 10, 2014, onclive the bcrabl t315i mutation compromises survival in chronic phase chronic myelogenous leukemia patients resistant to tyrosine kinase inhibitors, in a matched pair analysis may 28, 20, haematologica ponatinib thwarts t315i gene mutation in chronic myeloid leukemia. Resistance mechanisms, bcrabl mutations, and monitoring. Thirdgeneration tyrosine kinase inhibitors show clinical ac. A t315i mutation was the most common mutation, followed by f359v and m244v. A singletube allele specificpolymerase chain reaction aspcr method was developed to. Bcrabl1 was one of the first tyrosine kinases to be implicated in a human malignancy and the first to be successfully targeted. Authors reported improved survival with ponatinib only among cml patients in the chronic phase. T315imutated bcrabl in chronic myeloid leukemia and. Targeted therapy of philadelphiapositive all and cml patients using imatinib im has caused significant changes in treatment course and has increased the survival of patients. Molecular screening for t315i and f317l resistance mutations in. A straightforward traffic lightlike code is superimposed on experimental data so that these tables look like a sort of at. University of colorado denver school of medicine, department of biochemistry and molecular genetics, l189103, mail stop 8101.
However, most patients with advanced disease relapse despite continued treatment with sti571. This drug is the only one at this point that is showing good results against the dreaded t3151 mutation. As was mentioned in the section about targeted therapy, in some patients on tki treatment, the cancer cells develop a gene change called the t315i mutation that keeps most of the tkis from working. Although strategies to overcome resistancemediated t315i mutation may improve the survival of bcrabl. Studies show that twothirds of patients with a t315i mutation taking ponatinib achieve a mcyr and 58% achieve ccyr.
Allogeneic stem cell transplantation for patients with. Molecular dynamics simulations on 11 abl mutants demonstrated that large. Cdk4cdk6 inhibition as a novel strategy to suppress the. Nov 29, 2014 the mutation at amino acid 315 in the imatinibbinding site t315i mutation confers resistance to imatinib, dasatnib, and nilotinib by preventing access of these drugs to the atpbinding pocket. Mutation t315i chronic myeloid leukemia cml chronic. T315i dnazyme was designed to bind and cleave only the t315i mutation in abl mrna with a matched pyrimidine base u, boxed sequence in fig. We found that clinically reported bcrabl1 compound mutants center on 12 key. Homoharringtonine, omacetaxine mepesuccinate, and chronic. List the components of a ngs pipeline for testing of hematologic neoplasms 2. However, emergence of the t315i mutation has been found to be a main cause of failure after dasatinibcontaining treatments.
The results of the study confirmed that this method is low cost and easy tool to operate for t315i mutation screening and direct sequencing should be performed in positive cases for. Articles preclinical development of a novel bcrabl t315i inhibitor against chronic myeloid leukemia december 11, 2019, pubmed durable molecular remission in a lymphoid bpcml patient harboring t315i mutation treated with anticd19 cart therapy december, 2019, dovepress asciminib in chronic myeloid leukemia after abl kinase inhibitor failure december 12, 2019, the new england. Pdf the gatekeeper mutation t315i confers resistance. Overall survival with ponatinib versus allogeneic stem. May 05, 2020 25,26,4146 among the bcrabl mutations, there are 9 that account for more than 85% of all mutations. The use of imatinib resistance mutation analysis to direct. A costeffectiveness method for detection of abl mutations in. Sti571, a competitive inhibitor at the atpbinding site of bcrabl, has been shown to have high activity in this type of leukaemia. Thirdgeneration tyrosine kinase inhibitors show clinical.
After t315i mutation detection, secondgeneration tkis were used in 56% of cases, hydroxyurea in 39%, imatinib in 35%, cytarabine in 26%, mk0457 in 11%, stem cell transplantation in 17%, and. The mutation at amino acid 315 in the imatinibbinding site t315i mutation confers resistance to imatinib, dasatnib, and nilotinib by preventing access of these drugs to the atpbinding pocket. It does not form a hydrogen bond with the side chain of thr 315 in native abl. However, emergence of compound mutations in a bcrabl1 allele may confer ponatinib resistance. Bcrabl gene mutations in relation to clinical resistance. Incidence of t315i mutation in bcrablpositive cml and all. The durable clearance of the t315i bcrabl mutated clone in. The key structural feature of the molecule is a carboncarbon triple bond linkage that makes productive hydrophobic contact with the side chain of. Next generation sequencing of hematologic neoplasms todd w. Although the t315i mutation does not disturb the overall structure of the bcrabl protein, it affects the topology of the atp binding region.
Treatment options for people with chronic myeloid leukemia cml depend on the phase of their disease chronic, accelerated, or blast phase, their age, other prognostic factors, and the availability of a stem cell donor with matching tissue type chronic phase. Sensitive detection of resistant mutations may help pre. New strategies, including dosing titration of ponatinib and optimised control of vascular risk factors, might further improve outcomes. However, other report suggested a lack of impact of t315i mutation on survival. Panel a and b show t315i positive cells from a patient with 60 % of mutated cells positive cells, panel c and d show t315i positive cells from a patient with 45 % of mutated cells. Detection of bcrabl t315i mutation by peptide nucleic acid. Identity this position on the sequence and check if its indeed an isoleucine i. The t315i mutation is resistant to imatinib and secondgeneration tyrosine kinase inhibitors tkis.
The socalled t315i mutation involves the replacement of a threonine with an isoleucine at abl residue 315, which is present in up to 70% of patients who relapse after being treated with secondgeneration tyrosinekinase inhibitors. Bcrabl1 mutations in patients with imatinibresistant. Bcrabl1 kd mutations were detected in 30 50% of 60 patients. Thus, the usefulness of crisprcas9 system for functional analysis of somatic mutations in cancers was demonstrated. Bcrabl1 compound mutations combining key kinase domain. Twelve different mutations were found among 25 types of mutations selected in this study. This mutation, when engineered into wildtype wt p210bcrabl and transiently infected into 293t cells or baf3 cells, interfered with the inhibition of bcrabl kinase activity in cells exposed to imatinib 14, 18. Allogeneic stem cell transplantation sct is currently the only curative treatment option for chronic myeloid leukemia cml patients with bcrabl t315i mutations.
The structure is determined in complex with the smallmolecule inhibitor vx680 vertex pharmaceuticals, cambridge, ma, which blocks the activity of various imatinibresistant mutant forms of abl, including one t315i that is resistant to both imatinib and bms354825 dasatinib, a dual srcabl inhibitor that seems to be clinically effective. Find, read and cite all the research you need on researchgate. The results shown that only t315i mutation was detected in one im. A singletube allele specificpolymerase chain reaction to. Accordingly, t315i yields imatinib resistance more strongly than other point mutations figure 425. Drug hydrogen atoms, water molecules, and counterions are omitted for clarity. Pdf inhibitors of abl and the ablt315i mutation researchgate. T315i bcrabl mutation analysis quantitative indication. Patients with acute lymphoblastic leukaemia all positive for the philadelphia chromosome and patients with chronic myeloid leukaemia cml were studied.
The t315i mutation occurs in approximately 15% of imatinibresistant patients with a abl kinase domain mutation and may be more frequently detected in patients with advanced cml and ph. Aug 23, 2010 mutation specific control of bcrabl t315i positive leukemia with a recombinant yeastbased therapeutic vaccine in a murine model author links open overlay panel melanie r. New orleansseveral thirdgeneration tyrosine kinase inhibitors tkis have shown clinical activity in patients with chronic myeloid leukemia cml who harbor the bcrabl t315i mutation and are resistant to firstline therapy with imatinib and secondline therapy with secondgeneration tkis, according to data reported here at the ash annual meeting. Comparison of frequency and sensitivity of bcrabl1 kinase. The t315i mutation is a particularly relevant target. Resistance to tyrosine kinase inhibitor tkis therapy is associated with the development of kinase domain mutations. The t315i mutation is the most resistant to inhibition because of a combination of several factors, including steric hindrance of drug binding, loss of a key hydrogenbonding interaction with the. Incidence of t315i mutation in bcrablpositive cml and. Also, this identifier remains the same between different assemblies grch37 and grch38. Dasatinib combined with interferonalfa induces a complete. The t315i is a unique mutation because of its resistance to all approved bcrabl inhibitors, prior to ponatinib. Aug 20, 2007 in this study, we present the crystal structure of the kinase domain of the c. Detection of bcrabl t315i mutation by peptide nucleic.
Allogeneic stem cell transplantation for patients with t315i. Mutation specific control of bcrabl t315i positive leukemia with. The mutation of interest, t315i, is at the position described as pdb 315. Energy minimization refinement was performed on the peptides in cns. For monitoring of the levels of the thr to ile mutation at codon 315 t315i of the bcrabl kinase seen in cml patients who have developed resistance to imatinib or other kinase inhibitors.
This identifier is trackable and stable between different versions of the release. In the typical bcrabl, this position is the amino acid threonine t, but in this mutated variant, the amino acid is isoleucine i. This abnormality was discovered by peter nowell in 1960 and is a consequence of fusion between the abelson tyrosine kinase gene at. The same trend was observed for mutations identified in patients with cml as clinically resistant to nilotinib and bosutinib. Sixteen mutations showed intermediate activity to complete resistance to glivec. Ponatinib ap24534, iclusig is a multitargeted tki optimized using structurebased drug design to bind to the inactive conformation of abl and abl t315i. Associate professor of pathology university of utah medical director of molecular hematopathology arup laboratories salt lake city, utah usa faculty disclosures.
989 1116 1229 326 1435 1287 961 1428 184 44 507 396 1347 1419 466 1389 445 484 544 262 49 530 1346 551 846 324 487 2 1243 131 1475 1621 196 405 566 368 1347 644 173 553 72 13 1094 153 1021 562 448 1378