CASE STUDY ctdna-guided Change f Therapy Imprves Quality f Life f a Lung Cancer Patient Quick Summary Tripti Vasudev*, aged 61 years, was diagnsed with NSCLC. Genetic analysis revealed the presence f an mutatin - L858R at the initiatin f therapy. The patient was prescribed Afatinib as a first-line therapy. Hwever, lung cancer persisted and the patient was advised t underg a rebipsy as well as the Strand Liquid Bipsy Test (Strand Advantage Sense & Resist Tests) t understand the verall tumr hetergeneity. High systemic tumr burden, with a distinct bias twards the T790M mutatin, was nted in the analysis f ctdna by liquid bipsy. The patient was switched t Osimertinib therapy and further prgressin f the patient is being mnitred using peridic liquid bipsies. An accurate assessment f verall tumr lad as well as tumr clnality is prvided by a cmbinatin f liquid and slid bipsies. Cncurrent evaluatin f slid tumr tissue as well as liquid bipsy led t cmprehensive evaluatin f a patient, leading t better therapeutic chices. Genetic analysis f the secnd lung cancer bipsy ALONE wuld have supprted the cntinuatin f Afatinib therapy, eventually leading t failure f therapy. Intrductin Lung cancer has the distinctin f being the cancer with the fastest fatality. In mst cases, the verall survival f lung cancer patients is n lnger than 9-12 mnths pst-diagnsis (Murali et al. 2017). In India, the prevalence t incidence rati f lung cancer is the lwest amngst all cancer cases. CANCER Breast Cervix Ovary Stmach Lung Muth Lifetime PREVALENCE / INCIDENCE RATIO (Takiar & Jayant 2013) 5 5 3 1 1 4 3 Table 1. Prevalence / Incidence Rati fr Lung Cancer is the lwest in India (Takiar & Jayant 2013). * Name changed t prtect patient privacy 2018 Strand Life Sciences CASE STUDY : ctdna-guided Change f Therapy Imprves Quality f Life f a Lung Cancer Patient
Cnsidering the rapid lss f health f lung cancer patients, prgnstic aids that can help t assess the status f a patient during therapy wuld be f tremendus value. Althugh imaging techniques like PET-CT are available, newer technlgies like liquid bipsy t btain a sample f tumr DNA (knwn as ctdna) can be used very effectively t assess patient status (Marmarelis et al. 2017; Vendrell et al. 2017; Hu et al. 2017). Patient Prfile Tripti Vasudev, a retired accuntant aged 61 years, had mved frm Patna t Bhubaneshwar in 2015. She was glad t escape the pllutin f Patna and lked frward t a healthy and quiet retirement. Despite relcating t a cleaner envirnment, she nticed that her persistent lw cugh had nt gne away. In fact, her breathing difficulties had increased slwly but steadily. She cnsulted a renwned dctr in Bhubaneshwar wh advised her t underg a CT-scan t understand the rt cause f her prblems. Small areas f abnrmal grwth (ndules) were evident in the CT-images and hence Tripti was advised t underg a lung bipsy t withdraw a sample f the tissue. Histpathlgical investigatins cnfirmed that Tripti had develped Nn-Small Cell Lung Cancer (NSCLC), type adencarcinma. A full bdy scan revealed the presence f similar ndules all ver the bdy as well. Treatment Optins Tripti was advised treatment with Afatinib, a targeted therapy mlecule. This drug inhibits the activity f the prtein, which is mutated in mst adencarcinma cases. Hwever, her nclgist nted that the tumr persisted and respnse t Afatinib therapy waned, a few mnths int the therapy. A fresh bipsy f the lung tumr was advised t understand the genetic prfile f the persistent NSCLC, in a secnd attempt. The StrandAdvantage 48-gene Test was prescribed fr identificatin f mutant genes as well as ther mlecular markers. Tripti s nclgist als advised her t take advantage f nvel liquid bipsy tests which can facilitate tracking f the tumr via a bld sample, at any pint f time, during the therapy. Results f Genetic Testing The StrandAdvantage 48-gene Test, a pan-cancer test was prescribed fr Ms. Tripti Vasudev, in the secnd bipsy f her lung cancer. This test is designed t identify mutatins in genes that are mutated in mst slid tumrs. Therapy Tested Marker(s) Relevant Marker(s) Likelihd f Respnse** Osimertinib T790M Enhanced Afatinib, ERBB2, KRAS, MET Limited - Enhanced Gefitinib, ERBB2, KRAS, MET Pr Erltinib, ERBB2, KRAS, MET Pr Table 2. Genetic Analysis f the Secnd Lung Bipsy- Slid Tissue Sample Tripti s lung cancer tissue shwed tw mutatins in the gene, namely L858R and T790M. Tumrs bearing these mutatins can be effectively targeted with drugs like Afatinib and Osimertinib, respectively. Afatinib therapy had already been administered t her, during the preceding mnths. In rder t assess the tumr burden present in ther rgan systems as well, a liquid bipsy test fr detectin f tumr DNA in the bld was als perfrmed. A Liquid Bipsy fr cancer is a nvel Bld Test fr cancer. Cancer cells, like nrmal cells, shed DNA int the bld as a part f regular tissue turnver. This DNA is knwn as cell-free DNA (cfdna). It is pssible t extract cfdna frm bld and then check fr the presence f DNA released by cancer cells. DNA derived frm cancer cells is called circulating tumr DNA (ctdna). The amunt f ctdna present in the bld is a gd indicatr f the ttal tumr burden, present in a patient. 2018 Strand Life Sciences CASE STUDY : ctdna-guided Change f Therapy Imprves Quality f Life f a Lung Cancer Patient
Analysis f ctdna frm the Liquid Bipsy Sample Cllectin Date Test Gene Mutatin Result Cpies/ ml plasma 19-May-2017 Strand Liquid Bipsy L858R T790M 1,195,000 253,000 Table 3. -Sense and Resist Tests- Liquid Bipsy Sample The mutatins identified in the slid tumr sample were als detected in the liquid bipsy sample that had been taken frm the patient at the same time. Mrever, the number f cpies f ctdna present per ml f plasma indicated that the tumr burden in Tripti is very high. In fact, Tripti is ne f the rare patients wh were able t survive despite having such a high tumr lad. Since Tripti had been underging Afatinib therapy, the prevalence f the L858R mutatin was lwer than that f the T790M mutatin. These results indicated that her lung cancer was changing its genetic prfile and cells with the T790M mutatin were becming mre dminant than cells which respnd t Afatinib treatment. Figure 1. Simultaneus Genetic Analyses f Slid & Liquid Bipsies 2018 Strand Life Sciences CASE STUDY : ctdna-guided Change f Therapy Imprves Quality f Life f a Lung Cancer Patient
Cmparisn with Lung Bipsy The prevalence f the same mutatins in the secnd lung tissue bipsy was als assessed. Sample Cllectin Date Test Gene Mutatin Result Cpies/ ml plasma Slid Tumr Result (DNA Surce: FFPE) 06-May-2017 Strand Advantage TST Lung L858R T790M 54.48% 23.76% Table 4. Prevalence f Mutatins in the Secnd Slid Lung Bipsy Genetic analysis f the slid tumr (secnd lung bipsy sample) shws that the L858R mutatin is the mre prevalent ne cmpared t the T790M mutatin. Hwever, since the cancer is metastatic, the verall tumr burden and the predminant tumr gentype present in the rest f the bdy were assessed with greater accuracy via the liquid bipsy test. Change in Therapeutic Regimen The evlutin f lung cancer frm Afatinib sensitivity t resistance has been dcumented in several studies. Emergence f the T790M mutatin is ne f the mechanisms that can make lung cancer resistant t Afatinib therapy (Xing et al. 2017; Facchinetti et al. 2017). Cnsidering the high prevalence f the T790M mutatin in the liquid bipsy result, Afatinib therapy was terminated fr Tripti in August 2017. Instead, she is nw underging therapy with Osimertinib a drug that is designed t target cells with the T790M mutatin. As f Nvember 2017, Tripti is respnding well t the new treatment. Mnitring Prgressin Tracking the prgressin f pssible resistance t Osimertinib as well as develpment f ther genmic rearrangements is nw pssible using subsequent Liquid Bipsy tests. Cnclusins In Tripti s case, the prgnstic technique that prvided greater insight int her verall tumr lad was the assessment f ctdna in the liquid bipsy sample. Genetic analysis f the secnd lung cancer bipsy ALONE wuld have supprted the cntinuatin f Afatinib therapy, eventually leading t failure f therapy. An accurate assessment f verall tumr burden as well as the emerging dminance f the T790M mutatin was prvided by liquid bipsy based detectin and quantificatin f ctdna. Liquid bipsy tests can be perfrmed, at physicians discretin, withut the encumbrance f radiactive tracers and specialized imaging equipment. Rapid change f therapy frm ne targeted therapy drug t the next apprpriate ne has imprved the quality f life f the patient and prvided further ptins fr therapy. The cmbinatin f genetic analysis f the slid tumr and the liquid bipsy sample prved t be highly advantageus t the patient. If the liquid bipsy test had been verlked, Tripti wuld have cntinued t receive ONLY Afatinib treatment with the result that Afatinib resistant lung cancer cells wuld have cntinued t grw in her bdy. Massive metastasis wuld have increased her risk fr fatality. Instead, the liquid bipsy results prved t be a warning, just in time. The cmprehensive genetic prfile f the tumr, in the lungs as well as frm all ver the bdy, was the deciding factr in the chice f anther targeted therapy drug that increased her quality f life. 2018 Strand Life Sciences CASE STUDY : ctdna-guided Change f Therapy Imprves Quality f Life f a Lung Cancer Patient
References Facchinetti, F. et al., 2017. Mechanisms f Resistance t Target Therapies in Nn-small Cell Lung Cancer. In Handbk f experimental pharmaclgy. Available at: http://www.ncbi.nlm.nih.gv/pubmed/28332047 [Accessed Nvember 28, 2017]. Hu, H. et al., 2017. Discvery f targetable genetic alteratins in advanced nn-small cell lung cancer using a next-generatin sequencing-based circulating tumr DNA assay. Scientific reprts, 7(1), p.14605. Available at: http://www.ncbi.nlm.nih.gv/pubmed/29097733 [Accessed Nvember 21, 2017]. Marmarelis, M. et al., 2017. Emerging uses f circulating tumr DNA in advanced stage nn-small cell lung cancer. Annals f translatinal medicine, 5(18), p.380. Available at: http://www.ncbi.nlm.nih.gv/pubmed/29057240 [Accessed Nvember 22, 2017]. Murali, A.N. et al., 2017. Outcmes in Lung Cancer: 9-Year Experience Frm a Tertiary Cancer Center in India. Jurnal f Glbal Onclgy, 3(5), pp.459 468. Available at: http://www.ncbi.nlm.nih.gv/pubmed/29094084 [Accessed Nvember 27, 2017]. Takiar, R. & Jayant, K., 2013. A mdel apprach t calculate cancer prevalence frm 5 year survival data fr selected cancer sites in India. Asian Pacific jurnal f cancer preventin: APJCP, 14(11), pp.6899 903. Available at: http://www.ncbi.nlm.nih.gv/pubmed/24377623 [Accessed Nvember 20, 2017]. Vendrell, J. et al., 2017. Circulating Cell Free Tumr DNA Detectin as a Rutine Tl frlung Cancer Patient Management. Internatinal Jurnal f Mlecular Sciences, 18(2), p.264. Available at: http://www.mdpi.cm/1422-0067/18/2/264 [Accessed March 13, 2017]. Xing, L. et al., 2017. Dynamics f mutatins in plasma recapitulates the clinical respnse t -TKIs in NSCLC patients. Onctarget, 8(38), pp.63846 63856. Available at: http://www.ncbi.nlm.nih.gv/pubmed/28969034 [Accessed Nvember 28, 2017]. Strand Center fr Genmics & Persnalized Medicine (A unit f Strand Life Sciences Pvt. Ltd.) UAS Alumni Assciatin Building, Veterinary Cllege Campus, Bellary Rad, Hebbal, Bangalre 560 024 Phne: 1800-1022-695, supprt.strandx@strandls.cm, www.strandls.cm Strand Center fr Genmics & Persnalized Medicine is accredited by # 8750941 Certificate N. MC-2434 Strand ID: LB-47403012018 2018 Strand Life Sciences