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Geoffrey R. Oxnard



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    MA 07 - ALK, ROS and HER2 (ID 673)

    • Event: WCLC 2017
    • Type: Mini Oral
    • Track: Advanced NSCLC
    • Presentations: 1
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      MA 07.08 - Clinical Implications of ALK Resistance Mutations: Institutional Experience and Launch of Remote Participation Study (ID 7931)

      15:45 - 17:30  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      ALK resistance mutations are detected in 30-50% of the patients with ALK-positive non-small cell lung cancer (NSCLC) and resistance to ALK tyrosine kinase inhibitors (TKIs). Preliminary data suggests that TKI-resistant patients benefit from further ALK inhibition based on the specific resistant mutations, but clinical data are limited.

      Method:
      Patients with ALK-positive NSCLC were identified from our institutional database with IRB approval. Tumor specimens from patients with TKI-resistance were analyzed using next-generation sequencing (NGS). We aimed to study the relationship between specific ALK-resistant mutations, patient characteristics and clinical outcomes.

      Result:
      Among 82 ALK-positive NSCLC patients, we identified 29 cases with advanced disease, TKI resistance, and specimens available for NGS. Twenty-two specimens from 19 patients were adequate for genomic analyses. Patients received a median of 4 lines of treatment for advanced disease including a median of 2 ALK TKIs, with a median overall survival (OS) of 3.3 years. In 9 of 22 specimens, crizotinib was the only TKI received. Ten specimens (45.5%) showed an ALK resistance mutation: one G1128A, one L1152R, four I1171N/T, two F1174V and two G1202R. ALK-resistance mutations were more common with EML4-ALK variant 3 (4/5) than variant 1 (1/5). Three cases with sequential biopsies showed features of tumor evolution, such as a compound mutation (I1171N + C1156Y) or a mutational change (L1152R to G1128A). One case initially had an EGFR L858R mutation, then acquired an ALK rearrangement, then acquired a G1202R mutation. OS was longer in 8 patients with secondary ALK mutation (5.5y) compared to 11 patients without (1.8 y). Using these learnings from an institutional cohort of ALK resistant patients, we designed and are launching a prospective study to characterize ALK TKI resistance, which uses remote-participation and plasma NGS to enroll patients from across the US. Patients with systemic progression while on a next-generation ALK TKI submit blood to a central lab for analysis and banking. Plasma NGS results are returned to the patient and their provider, and including expected TKI sensitivities for any identified ALK-resistance mutations. Through monitoring outcomes, this study can assess if molecularly-guided therapy for ALK TKI-resistance is feasible and effective.

      Conclusion:
      ALK resistance mutations arise in a large portion of patients and are associated with longer survival. The SPACEW-ALK study (Study of Plasma next-generation sequencing for remote Assessment, Characterization, Evaluation of patients With ALK drug resistance) uses plasma NGS and remote consent to assess ALK resistance and the feasibility of precision resistance therapy for these patients.

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    MA 20 - Recent Advances in Pulmonology/Endoscopy (ID 685)

    • Event: WCLC 2017
    • Type: Mini Oral
    • Track: Pulmonology/Endoscopy
    • Presentations: 1
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      MA 20.14 - Genotyping of Lung Cancer Using Cell-Free DNA (cfDNA) from Cytologic Supernatant (CSN) (ID 9057)

      14:30 - 16:15  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      Tumor genotyping is transforming lung cancer care but increasingly requires more tumor tissue. Advances in minimally invasive bronchoscopic techniques increase access to small lesions, but often result in smaller samples. With the advent of new cfDNA (“liquid biopsy”) genotyping technologies, we hypothesized that CSN might increase the yield from small FNAs, facilitating cancer genotyping.

      Method:
      We studied patients with known or suspected lung cancer undergoing FNAs. CSN, which is usually discarded, was collected under IRB approval. cfDNA was extracted after a hard spin (1600 Gs) and tested by both ddPCR (EGFR, KRAS mutations) and targeted next-generation sequencing (NGS).

      Result:
      14 patients with suspected or known lung cancer were studied at time of analysis (final diagnosis: 2 non-malignant, 9 adenocarcinomas, 1 small-cell carcinoma, 2 squamous cell carcinomas), including 12 EBUS-TBNAs and 2 CT-guided FNAs. Among 6 known KRAS and EGFR mutations, all could be detected with ddPCR of CSN, with allelic fraction (AF) ranging from 1%-46% (median 8.5%). No ddPCR false positives were seen across 9 cases. NGS analysis was piloted on 7 specimens; 5 failed due to insufficient residual DNA. In one specimen, an EGFR exon 19 deletion was detected at 6% AF (2% AF ddPCR). In the other, a BRAF V600E, PIK3CA E784D and TP53 V274F mutations were detected at 48% (46% AF ddPCR), 18% and 86% AF, respectively.

      Conclusion:
      Cytology supernatant, usually discarded, may be a rich source of fresh tumor DNA, increasing the yield from FNAs. This widely available biospecimen has potential for aiding resistance genotyping, reducing turnaround time of cancer genotyping, and possibly a future role in clarifying the malignant potential of non-diagnostic biopsies. Enrollment continues in order to optimize this biospecimen for NGS. Figure 1



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    MTE 20 - Liquid Biopsy (Sign Up Required) (ID 551)

    • Event: WCLC 2017
    • Type: Meet the Expert
    • Track: Biology/Pathology
    • Presentations: 1
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      MTE 20.02 - Recent Advances in Liquid Biopsy (ID 7775)

      07:00 - 08:00  |  Presenting Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Abstract:
      Genotyping of plasma cell-free DNA (cfDNA) is rapidly changing our management approach for genotype-defined lung cancers. Widely available assays now have the ability to noninvasively identify driver mutations in cfDNA, monitor response to therapy, and characterize emerging resistance. However, such liquid biopsies also have clear limitations – existing assays are unlikely to replace tumor biopsies completely. This presentation will discuss an optimal approach for integrating liquid biopsies into lung cancer care, while also envisioning how liquid biopsies may become a routine part of lung cancer treatment in the years ahead.

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    OA 06 - Global Tobacco Control and Epidemiology I (ID 662)

    • Event: WCLC 2017
    • Type: Oral
    • Track: Epidemiology/Primary Prevention/Tobacco Control and Cessation
    • Presentations: 1
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      OA 06.02 - Final Report of the INHERIT EGFR Study - 33 Unrelated Kindreds Carrying Germline EGFR Mutations (ID 9370)

      15:45 - 17:30  |  Presenting Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      Anecdotal reports of families carrying germline EGFR mutations force us to reconsider our understanding of inherited lung cancer risk in non-smokers. We launched this prospective trial (NCT01754025; ALCMI-002) to remotely enroll and characterize these rare families.

      Method:
      Eligible subjects were recruited at participating cancer centers or through an online referral system. Following consent (in person or by phone), subjects received genetic counseling and sequencing of saliva or blood for germline EGFR mutations. Cancer specimens and CT scans were additionally analyzed when available.

      Result:
      Between 12/2012-6/2017, 105 participants were enrolled from 30 US states. Germline EGFR mutations were found in 63% of patients (31 of 49) with EGFR T790M in their lung cancer at diagnosis, and in 62% (16 of 27) and 44% (4 of 9) of first- and second-degree relatives of germline carriers. Pedigrees were available for 32 unrelated kindreds (31 germline T790M, 1 germline R776H): 4 with no family history of lung cancer, 8 with a family history of lung cancer in non-smokers, 18 with multiple relatives with lung cancer. Characteristics of 31 lung cancer probands: median age of lung cancer diagnosis was 57 (range 28-82); 81% white, 19% black; 52% never-smokers; 65% stage IV at diagnosis; 65% were from states in or bordering the US Southeast. Tumor genotyping revealed somatic EGFR co-mutations in 29 (94%) of probands: 6 exon 19 del, 12 L858R, 6 G719X, 1 exon 19 del & G719R, 1 L861Q, 2 H773R, 1 V774M. Imaging analysis suggests a unique pattern of cancer evolution including an indolent multi-focal nodular phase which then progresses to lymph nodes and then remote metastatic disease. Of 8 probands with sensitizing EGFR co-mutations treated with osimertinib, no unexpected toxicities were seen, and 4 have had durable benefit exceeding 12 months. Of 9 relatives with germline EGFR mutations and CT imaging available, 2 have a lung cancer diagnosis and 6 others have lung nodules.

      Conclusion:
      This study confirms the high likelihood of a germline mutation in lung cancer patients with EGFR T790M detected at diagnosis, and suggests a risk of lung nodules and lung cancer in germline carriers. The regional enrichment in the US Southeast suggests a possible founder effect; haplotyping is planned. A registry is under development to continue follow-up of these rare individuals. Further investigation of germline risk alleles associated with lung cancer risk in non-smokers is needed. Funding: Bonnie J. Addario Lung Cancer Foundation, Conquer Cancer Foundation of ASCO.

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    OA 09 - EGFR TKI Resistance (ID 663)

    • Event: WCLC 2017
    • Type: Oral
    • Track: Advanced NSCLC
    • Presentations: 2
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      OA 09.02 - Osimertinib Resistance Mediated by Loss of EGFR T790M Is Associated with Early Resistance and Competing Resistance Mechanisms (ID 9000)

      11:00 - 12:30  |  Presenting Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      Osimertinib is a third-generation EGFR tyrosine kinase inhibitor (TKI) active in EGFR-mutant NSCLC with resistance to prior TKI. Improved understanding of the clinical and molecular characteristics of acquired resistance to osimertinib is needed.

      Method:
      We initially studied resistance biopsies and plasma specimens from an institutional cohort of 119 patients treated with osimertinib for T790M-positive NSCLC with resistance to prior TKI. For validation, we studied plasma from 157 patients treated with osimertinib on the AURA trial (NCT01802632).

      Result:
      45 of 119 patients underwent a resistance biopsy and 33 had resistance tumor genotyping available. 11 patients maintained T790M at resistance: 7 acquired EGFR C797S, 1 had a PIK3CA mutation. 22 patients had loss of T790M at resistance: 14 harbored a competing resistance mechanism, including histologic transformation to SCLC, MET amplification, mutations in BRAF, PIK3CA, or KRAS, or fusions in RET or FGFR. Median time to treatment failure (TTF) on osimertinib was 3 months in patients with loss of T790M and 15 months in patients with maintained T790M. In the validation cohort, 110 of 157 patients had detectable tumor DNA in plasma and were eligible for analysis. 58 patients (53%) maintained T790M at resistance; 24 (22%) also acquired a C797S mutation. 52 patients (47%) had loss of T790M at resistance and no C797S. Median TTF was shorter in patients with loss of T790M than in those with maintained T790M at resistance (5.7 vs 12.5 months). 50 patients had both pre- and post-osimertinib plasma genotyping. Studying the relative allelic fraction (AF) of T790M compared to driver EGFR mutation, patients with T790M loss had only slightly lower relative T790M AF pretreatment (29% vs. 38% median, p = 0.06). The ability of plasma response to predict subsequent resistance was studied in 19 patients from the initial cohort with baseline and follow-up plasma genotyping after 1-3 weeks on osimertinib. Studying the difference between the relative change in plasma levels of T790M and the EGFR driver, patients with T790M loss at time of resistance consistently had a greater T790M response than driver response (median difference 16%), suggesting incomplete suppression of the driver due to competing resistance mechanisms.

      Conclusion:
      In patients with acquired resistance to osimertinib, repeat testing for T790M could offer key insights into disease biology. Patients with early resistance on osimertinib are at risk of T790M loss with emergence of a complex variety of competing resistance mechanisms, and represent intuitive candidates for combination approaches such as combined EGFR & MET inhibition.

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      OA 09.03 - TATTON Ph Ib Expansion Cohort: Osimertinib plus Savolitinib for Pts with EGFR-Mutant MET-Amplified NSCLC after Progression on Prior EGFR-TKI (ID 8985)

      11:00 - 12:30  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      MET amplification is a well described mechanism of acquired resistance to EGFR inhibition in EGFR-mutant NSCLC, making combined MET/EGFR inhibition a compelling therapeutic approach. We previously reported tolerability of the oral, CNS active, third-generation EGFR-TKI osimertinib, which is selective for both EGFR-TKI sensitizing and EGFR T790M resistance mutations, combined with the highly selective MET-TKI savolitinib (volitinib, HMPL-504, AZD6094). Here we assess safety and preliminary activity of this combination in a cohort of patients (pts) with EGFR-mutant NSCLC and MET-positive acquired resistance in the multi-arm, Phase Ib TATTON study (NCT02143466).

      Method:
      Eligible pts were aged ≥18 years (WHO performance status 0/1) with locally advanced or metastatic EGFR-mutant NSCLC who progressed on at least one prior EGFR-TKI with centrally confirmed MET-amplification (fluorescence in-situ hybridisation, MET gene copy ≥5 or MET/CEP7 ratio ≥2). Pts received osimertinib 80 mg QD plus savolitinib 600 mg QD. Primary objective was safety and tolerability; secondary objectives included preliminary assessment of anti-tumour activity and pharmacokinetics.

      Result:
      As of data-cut off (15 April 2017), 45 pts with centrally confirmed MET-amplification (FISH) were enrolled and received treatment, including 25 pts previously treated with a third-generation EGFR-TKI and 20 without prior third-generation EGFR-TKI treatment (T790M negative n=13; T790M positive n=7). At baseline, median age was 58 years (range 38–76), 24 (53%) were female, 36 (80%) were Asian. The most frequent adverse events (AEs) were nausea (n=21, 47%), decreased appetite (n=15, 33%), fatigue (n=13, 29%) vomiting (n=13, 29%), rash (n=11, 24%), myalgia (n=8, 18%), pyrexia (n=7, 16%), ALT/AST increased (n=6, 13%), and WBC decreased (n=6, 13%), consistent with the known safety profiles. Serious AEs were reported in 15 (33%) pts; events reported in >1 patient were pneumonia, dyspnoea, acute kidney injury and pyrexia (all n=2). Four pts died due to AEs, none were considered related to study drugs. At data cut-off, confirmed partial responses were reported in 5/25 (20%) pts previously treated with a third-generation EGFR-TKI; 5/12 (42%) T790M negative pts without prior third-generation EGFR-TKI and 3/7 (43%) T790M positive pts without prior third-generation EGFR‑TKI. Twenty-eight (62%) pts are ongoing treatment. Preliminary steady-state exposures and pharmacokinetic parameters of savolitinib and osimertinib were consistent with historical data.

      Conclusion:
      These findings demonstrate promising safety, tolerability, and preliminary activity of osimertinib plus savolitinib and support further investigation of this combination for the treatment of pts with locally advanced or metastatic EGFR-mutant NSCLC and MET-amplification. Updated data will be presented.

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    OA 12 - Emerging Genomic Targets (ID 679)

    • Event: WCLC 2017
    • Type: Oral
    • Track: Advanced NSCLC
    • Presentations: 2
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      OA 12.02 - Final Results of a Phase 2 Study of the hsp90 Inhibitor Luminespib (AUY922) in NSCLC Patients Harboring EGFR Exon 20 Insertions (ID 10182)

      11:00 - 12:30  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      EGFR exon 20 insertions (ins20) comprise 4-10% of EGFR mutations in NSCLC and are refractory to 1[st]/2[nd] generation EGFR TKIs. No effective targeted therapies exist for patients with EGFR ins20. EGFR is a client protein of the molecular chaperone Heat Shock Protein 90 (hsp90). Here, we present the final results of a phase II investigator-initiated trial to assess the activity of the Hsp90 inhibitor luminespib (AUY922) in NSCLC patients with EGFR ins20 (NCT01854034).

      Method:
      Between 8/2013 and 10/2016, the study enrolled 29 patients with stage IV NSCLC, EGFR ins20 identified on local testing, ECOG PS 0-2, at least one prior line of therapy and no untreated brain metastases. The study was closed on 2/28/17 when the available drug supply was exhausted. Luminespib was given at 70mg/m2 IV weekly. Response was assessed by RECIST 1.1 every 6 weeks; treatment beyond progression was allowed. Dose interruptions and dose reductions were allowed as needed for toxicity management. Primary endpoint was ORR with a target disease control rate (DCR; PR/CR plus SD lasting > 3 mos) of > 20%. Secondary endpoints were PFS, OS, safety and response by EGFR ins20 subtype.

      Result:
      29 patients (18 female/11 male, median age 60 (range, 31-79)) were enrolled. Median number of prior therapies = 1 (range, 1-5.) 4/29 achieved PR and 1 CR (ORR 5/29; 17%). 15 patients had SD and 9 had PD as their best response. mPFS was 2.9 mos (95% CI, 1.4-5.6,) mOS was 13 mos (95% CI, 4.9-19.5.) DCR was 11/29 (38%). Among 19 patients with baseline PS 0-1 and < 2 prior therapies, ORR = 21% and mPFS = 5.1 mos (95% CI, 2.1-11.8.) The most common luminespib-related toxicities were visual changes (22/29; 76%) diarrhea (21/29; 72%) and fatigue (13/29; 45%). Treatment-related grade 3 toxicities included ocular toxicity (1/29; 3%), hypertension (3/29; 10%) and hypophosphatemia (1/29; 3%). All study treatment was stopped on 2/28/17 due to lack of drug availability; 3 patients were on treatment without progression at study termination.

      Conclusion:
      The study met its primary endpoint and suggests that luminespib may be an active therapy for advanced NSCLC patients with EGFR ins20. Luminespib is generally well-tolerated, though reversible low-grade ocular toxicity is common. Further study of luminespib and other Hsp90 inhibitors in this population is warranted, as are novel systems to continue drug supply for benefitting patients when availability of experimental compounds is limited.

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      OA 12.07 - LOXO-292, a Potent, Highly Selective RET Inhibitor, in MKI-Resistant RET Fusion-Positive Lung Cancer Patients with and without Brain Metastases (ID 10955)

      11:00 - 12:30  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Presentation
      • Slides

      Background:
      RET fusions are validated therapeutic targets in human lung cancers. However, the clinical activity of multikinase inhibitors (MKIs) with anti-RET activity is limited by a narrow therapeutic index from off-target effects and poor pharmacokinetics (PK). Moreover, MKIs have limited RET inhibition in the central nervous system (CNS), and patients often experience disease progression in the brain. LOXO-292 is a potent and highly selective RET inhibitor, with >100-fold selectivity versus important off-targets, and anti-tumor activity in the brain and periphery in RET-dependent tumor models in vivo.

      Method:
      Two RET fusion-positive lung cancer patients were treated with LOXO-292: a patient with CCDC6-RET-rearranged lung cancer with acquired resistance to RXDX-105; and a patient with KIF5B-RET-rearranged lung cancer with progressive disease in the brain while on alectinib treated under a single patient protocol with real-time, PK- guided intra-patient dose titration.

      Result:
      The first patient was enrolled on cohort 1 of the Phase 1 trial (20 mg daily) and was the first lung cancer patient to receive LOXO-292. She achieved a rapid, confirmed partial response (PR) by RECIST 1.1, with a 44% reduction in target lesion size. The second patient, the first to receive LOXO-292 in the setting of brain metastases, achieved a PR with escalating doses of LOXO-292 (20-60-100 mg twice daily) that included target lesion responses in both the lungs and brain (Figure 1), and resolution of cancer-related CNS symptoms. Early clinical experience with LOXO-292 has already established drug exposures that are consistent with significant RET inhibition in vitro and RET-dependent tumor regression in vivo. Importantly, LOXO-292 has been well-tolerated, with the majority of treatment-emergent adverse events reported as Grade 1-2, and none attributed to LOXO-292.

      Conclusion:
      LOXO-292 has demonstrated proof-of-concept tolerability, significant exposure, and efficacy in two patients with MKI-resistant, RET-dependent cancers, including a patient with progressive brain metastases after alectinib.Figure 1



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    P3.02 - Biology/Pathology (ID 620)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Biology/Pathology
    • Presentations: 1
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      P3.02-014 - Amplicon-Based Next-Generation Sequencing (NGS) of Plasma Cell-Free DNA (cfDNA) for Detection of Driver and Resistance Mutations in NSCLC (ID 10551)

      09:30 - 16:00  |  Author(s): Geoffrey R. Oxnard

      • Abstract
      • Slides

      Background:
      While several studies have evaluated hybrid-capture NGS for cfDNA genotyping, amplicon-based NGS is an attractive alternative with the potential to be faster and less expensive. We performed a blinded evaluation of this approach for the characterization and monitoring of the molecular profile of advanced NSCLC during genotype-directed therapy.

      Method:
      Plasma samples from patients with advanced NSCLC and a known targetable genotype (EGFR, BRAF, MET, HER2 mutations; ALK, ROS1 rearrangements) were collected and analyzed, blinded to tumor genotype, with IRB approval. Up to 4 specimens were collected for each patient: baseline, initial 2 follow-ups, and progression. Plasma NGS was performed using enhanced tagged amplicon sequencing of hotspots and coding regions from 36 genes. A novel approach was used to detect ALK/ROS1 fusions using amplicon sequencing in cfDNA. Diagnostic accuracy was compared to plasma ddPCR and tumor genotype (including NGS when available).

      Result:
      A total of 146 specimens from 49 patients were studied. Testing was completed for 115 specimens at the time of analysis. Matched plasma NGS and ddPCR were available across 95 samples and revealed high concordance of allelic fraction (AF). At baseline, sensitivity of plasma NGS for the detection of the driver was 100% (26/26) for EGFR (88.5% ddPCR sensitivity). Sensitivity for the detection of ALK/ROS1 fusions was 89% (6/7 ALK, 2/2 ROS1). Rare instances of plasma NGS-positive/tissue NGS-negative discordance were seen across 13 cases with match tumor NGS (3/442 genes sequenced) and appear related to resistance heterogeneity, clonal hematopoiesis, and low tumor content of biopsy. Among patients with acquired T790M and available specimens at osimertinib resistance (n=21), 11 resistance mechanisms could be detected including tertiary EGFR mutations (e.g. C797S), mutations in BRAF, PIK3CA, or KRAS, and amplification of MET, HER2, or FGFR1. 4 were detected pre-osimertinib.

      Conclusion:
      This blinded analysis demonstrates for the first time the ability of amplicon-based plasma NGS to detect a full range of targetable genotypes in NSCLC. This approach has attractive sensitivity and specificity and deserves further study as an alternative to better-established hybrid capture approaches. Serial plasma NGS can detect competing resistance mutations in patients with TKIs resistance, highlighting the pitfalls of PCR-based plasma assays in patients with heterogeneous resistance and paving the way towards combination therapies.

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