Acquired Cross-Resistance in Small Cell Lung Cancer due to Extrachromosomal DNA Amplification of MYC Paralogs

Small cell lung cancer (SCLC) presents as a highly chemosensitive malignancy but acquires cross-resistance after relapse. This transformation is nearly inevitable in patients but has been difficult to capture in laboratory models. Here, we present a preclinical system that recapitulates acquired cross-resistance, developed from 51 patient-derived xenograft (PDX) models. Each model was tested in vivo against three clinical regimens: cisplatin plus etoposide, olaparib plus temozolomide, and topotecan. These drug-response profiles captured hallmark clinical features of SCLC, such as the emergence of treatment-refractory disease after early relapse. For one patient, serial PDX models revealed that cross-resistance was acquired through MYC amplification on extrachromosomal DNA (ecDNA). Genomic and transcriptional profiles of the full PDX panel revealed that MYC paralog amplifications on ecDNAs were recurrent in relapsed cross-resistant SCLC, and this was corroborated in tumor biopsies from relapsed patients. We conclude that ecDNAs with MYC paralogs are recurrent drivers of cross-resistance in SCLC.

SIGNIFICANCE

SCLC is initially chemosensitive, but acquired cross-resistance renders this disease refractory to further treatment and ultimately fatal. The genomic drivers of this transformation are unknown. We use a population of PDX models to discover that amplifications of MYC paralogs on ecDNA are recurrent drivers of acquired cross-resistance in SCLC. This article is featured in Selected Articles from This Issue, p. 695.

Acquired Cross-resistance in Small Cell Lung Cancer due to Extrachromosomal DNA Amplification of MYC paralogs

Small cell lung cancer (SCLC) presents as a highly chemosensitive malignancy but acquires cross-resistance after relapse. This transformation is nearly inevitable in patients but has been difficult to capture in laboratory models. Here we present a pre-clinical system that recapitulates acquired cross-resistance in SCLC, developed from 51 patient-derived xenografts (PDXs). Each model was tested for in vivo sensitivity to three clinical regimens: cisplatin plus etoposide, olaparib plus temozolomide, and topotecan. These functional profiles captured hallmark clinical features, such as the emergence of treatment-refractory disease after early relapse. Serially derived PDX models from the same patient revealed that cross-resistance was acquired through a MYC amplification on extrachromosomal DNA (ecDNA). Genomic and transcriptional profiles of the full PDX panel revealed that this was not unique to one patient, as MYC paralog amplifications on ecDNAs were recurrent among cross-resistant models derived from patients after relapse. We conclude that ecDNAs with MYC paralogs are recurrent drivers of cross-resistance in SCLC.

SIGNIFICANCE

SCLC is initially chemosensitive, but acquired cross-resistance renders this disease refractory to further treatment and ultimately fatal. The genomic drivers of this transformation are unknown. We use a population of PDX models to discover that amplifications of MYC paralogs on ecDNA are recurrent drivers of acquired cross-resistance in SCLC.

Combination lurbinectedin and doxorubicin versus physician's choice of chemotherapy in patients with relapsed small-cell lung cancer (ATLANTIS): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Lurbinectedin is a synthetic marine-derived anticancer agent that acts as a selective inhibitor of oncogenic transcription. Lurbinectedin monotherapy (3·2 mg/m² every 3 weeks) received accelerated approval from the US Food and Drug Administration on the basis of efficacy in patients with small-cell lung cancer (SCLC) who relapsed after first-line platinum-based chemotherapy. The ATLANTIS trial assessed the efficacy and safety of combination lurbinectedin and the anthracycline doxorubicin as second-line treatment for SCLC.

METHODS

In this phase 3, open-label, randomised study, adult patients aged 18 years or older with SCLC who relapsed after platinum-based chemotherapy were recruited from 135 hospitals across North America, South America, Europe, and the Middle East. Patients were randomly assigned (1:1) centrally by dynamic allocation to intravenous lurbinectedin 2·0 mg/m² plus doxorubicin 40·0 mg/m² administered on day 1 of 21-day cycles or physician's choice of control therapy (intravenous topotecan 1·5 mg/m² on days 1-5 of 21-day cycles; or intravenous cyclophosphamide 1000 mg/m², doxorubicin 45·0 mg/m², and vincristine 2·0 mg on day 1 of 21-day cycles [CAV]) administered until disease progression or unacceptable toxicity. Primary granulocyte-colony stimulating factor prophylaxis was mandatory in both treatment groups. Neither patients nor clinicians were masked to treatment allocation, but the independent review committee, which assessed outcomes, was masked to patients' treatment allocation. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02566993, and with EudraCT, 2015-001641-89, and is complete.

FINDINGS

Between Aug 30, 2016, and Aug 20, 2018, 613 patients were randomly assigned to lurbinectedin plus doxorubicin (n=307) or control (topotecan, n=127; CAV, n=179) and comprised the intention-to-treat population; safety endpoints were assessed in patients who had received any partial or complete study treatment infusions (lurbinectedin plus doxorubicin, n=303; control, n=289). After a median follow-up of 24·1 months (95% CI 21·7-26·3), 303 patients in the lurbinectedin plus doxorubicin group and 289 patients in the control group had discontinued study treatment; progressive disease was the most common reason for discontinuation (213 [70%] patients in the lurbinectedin plus doxorubicin group vs 152 [53%] in the control group). Median overall survival was 8·6 months (95% CI 7·1-9·4) in the lurbinectedin plus doxorubicin group versus 7·6 months (6·6-8·2) in the control group (stratified log-rank p=0·90; hazard ratio 0·97 [95% CI 0·82-1·15], p=0·70). 12 patients died because of treatment-related adverse events: two (<1%) of 303 in the lurbinectedin plus doxorubicin group and ten (3%) of 289 in the control group. 296 (98%) of 303 patients in the lurbinectedin plus doxorubicin group had treatment-emergent adverse events compared with 284 (98%) of 289 patients in the control group; treatment-related adverse events occurred in 268 (88%) patients in the lurbinectedin plus doxorubicin group and 266 (92%) patients in the control group. Grade 3 or worse haematological adverse events were less frequent in the lurbinectedin plus doxorubicin group than the control group (anaemia, 57 [19%] of 302 patients in the lurbinectedin plus doxorubicin group vs 110 [38%] of 288 in the control group; neutropenia, 112 [37%] vs 200 [69%]; thrombocytopenia, 42 [14%] vs 90 [31%]). The frequency of treatment-related adverse events leading to treatment discontinuation was lower in the lurbinectedin plus doxorubicin group than in the control group (26 [9%] of 303 patients in the lurbinectedin plus doxorubicin group vs 47 [16%] of 289 in the control group).

INTERPRETATION

Combination therapy with lurbinectedin plus doxorubicin did not improve overall survival versus control in patients with relapsed SCLC. However, lurbinectedin plus doxorubicin showed a favourable haematological safety profile compared with control.

FUNDING

PharmaMar.

Discovery, Preclinical Characterization, and Early Clinical Activity of JDQ443, a Structurally Novel, Potent, and Selective Covalent Oral Inhibitor of KRASG12C

Covalent inhibitors of KRASG12C have shown antitumor activity against advanced/metastatic KRASG12C-mutated cancers, though resistance emerges and additional strategies are needed to improve outcomes. JDQ443 is a structurally unique covalent inhibitor of GDP-bound KRASG12C that forms novel interactions with the switch II pocket. JDQ443 potently inhibits KRASG12C-driven cellular signaling and demonstrates selective antiproliferative activity in KRASG12C-mutated cell lines, including those with G12C/H95 double mutations. In vivo, JDQ443 induces AUC exposure-driven antitumor efficacy in KRASG12C-mutated cell-derived (CDX) and patient-derived (PDX) tumor xenografts. In PDX models, single-agent JDQ443 activity is enhanced by combination with inhibitors of SHP2, MEK, or CDK4/6. Notably, the benefit of JDQ443 plus the SHP2 inhibitor TNO155 is maintained at reduced doses of either agent in CDX models, consistent with mechanistic synergy. JDQ443 is in clinical development as monotherapy and in combination with TNO155, with both strategies showing antitumor activity in patients with KRASG12C-mutated tumors.

SIGNIFICANCE

JDQ443 is a structurally novel covalent KRASG12C inhibitor with a unique binding mode that demonstrates potent and selective antitumor activity in cell lines and in vivo models. In preclinical models and patients with KRASG12C-mutated malignancies, JDQ443 shows potent antitumor activity as monotherapy and in combination with the SHP2 inhibitor TNO155. This article is highlighted in the In This Issue feature, p. 1397.

Phase I/II investigator-initiated study of olaparib and temozolomide in SCLC: Updated analysis and CNS outcomes

8565

Background: Temozolomide has activity in small-cell lung cancer (SCLC), including patients (pts) with brain metastases (mets; Pietanza M, Clin Cancer Res 2012). Inhibition of Poly (ADP-ribose) polymerase (PARP) is another therapeutic strategy in SCLC. We hypothesized that olaparib plus temozolomide may be safe and effective for pts with relapsed SCLC and clinically active against CNS disease (Farago A, Cancer Discovery 2019). Here, we present an updated analysis of this combination in pts with relapsed SCLC, including a second cohort testing an alternative dosing strategy and an exploratory analysis of CNS-specific outcomes. Methods: In this phase I/II trial of olaparib plus temozolomide in pts with recurrent SCLC, pts were sequentially enrolled into two cohorts defined by dosing schedule. In cohort 1, olaparib was dosed on D1-7 of each 21d cycle. In cohort 2, olaparib was dosed on D1-21. Temozolomide was dosed on D1-7 in both cohorts. Each cohort had a phase I portion (conventional 3+3 dose-escalation) for determination of MTD and RP2D and a phase II portion with primary endpoint of ORR. Per protocol, eligible pts could have untreated asymptomatic brain mets < 1cm and, after mandatory baseline imaging, CNS imaging was performed at investigator’s discretion. A post-hoc exploratory analysis of CNS-specific outcomes was performed using modified RECIST criteria (Long GV, Lancet Oncol 2012) in which brain mets ≥5mm were considered measurable, and intracranial response was independently assessed by an attending radiologist. Results: 66 pts with median of 2 prior lines of therapy (range, 1-7) were enrolled, 50 pts in cohort 1 and 16 pts in cohort 2. 33/66 (50%) pts had history of brain mets, 15/66 (23%) pts had untreated brain mets at enrollment. The confirmed ORR of cohort 2 was 7% (1/14 evaluable pts, 95% CI: 0.2-33.9%), and the updated confirmed ORR of the entire study population was 34% (21/62 evaluable pts, 95% CI: 22.3-47.0%). The most common adverse events were hematologic toxicities (thrombocytopenia, anemia, and neutropenia). 22/50 (44%) of cohort 1 pts and 4/16 (25%) of cohort 2 pts required dose reduction. Of 15 pts with untreated brain mets, best overall intracranial response (including both confirmed and unconfirmed responses) was CR in 6 pts, PR in 4 pts, SD in 3 pts and PD in 1 for a CNS disease control rate of 87% (95% CI: 59.5-98.3%). Of 10 pts with CR/PR as their best intracranial response, 4 responses were confirmed. With non-CNS progression as a competing risk, the probability of CNS progression among the entire study population was 17% (95% CI: 8.8-26.7%) at 6 months and 21% (95% CI: 12.1-32.0%) at 12 months. Conclusions: Olaparib and temozolomide may be an effective therapy for relapsed SCLC, especially for pts with CNS disease where we observed a high rate of intracranial disease control. Ongoing analyses regarding optimal dosing schedule will inform potential for future use of this combination. Clinical trial information: NCT02446704.

Translesion DNA synthesis mediates acquired resistance to olaparib plus temozolomide in small cell lung cancer

In small cell lung cancer (SCLC), acquired resistance to DNA-damaging therapy is challenging to study because rebiopsy is rarely performed. We used patient-derived xenograft models, established before therapy and after progression, to dissect acquired resistance to olaparib plus temozolomide (OT), a promising experimental therapy for relapsed SCLC. These pairs of serial models reveal alterations in both cell cycle kinetics and DNA replication and demonstrate both inter- and intratumoral heterogeneity in mechanisms of resistance. In one model pair, up-regulation of translesion DNA synthesis (TLS) enabled tolerance of OT-induced damage during DNA replication. TLS inhibitors restored sensitivity to OT both in vitro and in vivo, and similar synergistic effects were seen in additional SCLC cell lines. This represents the first described mechanism of acquired resistance to DNA damage in a patient with SCLC and highlights the potential of the serial model approach to investigate and overcome resistance to therapy in SCLC.

Abstract LBA038: KontRASt: A Phase Ib/II, open-label, multi-center, dose-escalation study of JDQ443 in patients with advanced solid tumors harboring the KRAS G12C mutation

Background Kirsten rat sarcoma virus (KRAS) is a GTPase that regulates cell signaling pathways involved in cell proliferation, survival, and tumorigenesis. Somatic mutations in KRAS resulting in a glycine to cysteine substitution at codon 12 (KRAS G12C) lead to a shift toward active, GTP-bound KRAS and increased oncogenic signaling. KRAS G12C mutations occur in approximately 13% of non-squamous, non-small cell lung cancer (NSCLC) cases, and at lower frequencies in other solid tumor malignancies. JDQ443 (NVP-JDQ443) is a selective, covalent, and orally bioavailable investigational KRASG12C inhibitor that binds under the switch II loop, and irreversibly traps KRASG12C in a GDP-bound, inactive state. In preclinical models, JDQ443 potently inhibited KRASG12C cellular signaling and proliferation in a mutant-selective manner and demonstrated dose-dependent anti-tumor activity. In patients with KRAS G12C-mutated solid tumors, JDQ443 may have clinically significant antitumor activity alone and in combination with TNO155, an investigational, SHP2 inhibitor, and in combination with PD-1 blockade. Methods This is a Phase Ib/II, open-label, dose-escalation study with four arms: (A) JDQ443 monotherapy; (B) JDQ443 + TNO155; (C) JDQ443 + anti–PD-1; and (D) JDQ443 + TNO155 + anti–PD-1. Each arm has a dose-escalation portion followed by dose expansion at the maximum tolerated dose (MTD) and/or recommended dose (RD). The escalations are conducted in adult patients with advanced KRAS G12C-mutated solid tumors who have previously received standard-of-care therapies. Dose escalation is guided by an adaptive Bayesian hierarchical logistic regression model following the escalation with overdose control principle. Expansions are planned for patients with advanced (metastatic or unresectable), KRAS G12C-mutated NSCLC who have received prior immune checkpoint inhibitor therapy and platinum-based chemotherapy, and for patients with advanced, KRAS G12C-mutated colorectal cancer who have received prior fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy. The primary objectives of dose escalation are to assess the safety and tolerability of JDQ443 alone and in combinations, and to identify the MTD and/or the RD, and regimens for future studies. The primary objective of dose expansion is to evaluate the antitumor activity via overall response rates for JDQ443, both alone and in combinations, in selected populations. Secondary objectives for both escalation and expansion are to evaluate the antitumor activity and characterize the pharmacokinetics of JDQ443 alone and in combinations, and to assess the immunogenicity of anti–PD-1 in combination with JDQ443 or TNO155. Safety and tolerability will also be further assessed during dose expansion. The study is currently enrolling to the dose-escalation portions of Arm A (JDQ443 monotherapy) and Arm B (JDQ443 + TNO155). NCT04699188

Citation Format: Benjamin Solomon, Rebecca S Heist, Daniel SW Tan, Philippe A Cassier, Christophe Dooms, Eric Van Cutsem, Conor E Steuer, Neeltje Steeghs, Martin Schuler, Anas Gazzah, Martin Wermke, Enriqueta Felip, Herbert HF Loong, Maria J De Miguel Luken, Ross A Soo, Ashley Jaeger, Kun Xu, Xueying Chen, Xiaoming Cui, Heather Burks, Anna F Farago, Toshio Shimizu. KontRASt: A Phase Ib/II, open-label, multi-center, dose-escalation study of JDQ443 in patients with advanced solid tumors harboring the KRAS G12C mutation [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA038.

A phase I/II study of rovalpituzumab tesirine in delta-like 3-expressing advanced solid tumors

Delta-like protein 3 (DLL3) is highly expressed in solid tumors, including neuroendocrine carcinomas/neuroendocrine tumors (NEC/NET). Rovalpituzumab tesirine (Rova-T) is a DLL3-targeting antibody-drug conjugate. Patients with NECs and other advanced DLL3-expressing tumors were enrolled in this phase I/II study (NCT02709889). The primary endpoint was safety. Two hundred patients were enrolled: 101 with NEC/NET (large-cell NEC, gastroenteropancreatic NEC, neuroendocrine prostate cancer, and other NEC/NET) and 99 with other solid tumors (melanoma, medullary thyroid cancer [MTC], glioblastoma, and other). The recommended phase II dose (RP2D) was 0.3 mg/kg every 6 weeks (q6w) for two cycles. At the RP2D, grade 3/4 adverse events included anemia (17%), thrombocytopenia (15%), and elevated aspartate aminotransferase (8%). Responses were confirmed in 15/145 patients (10%) treated at 0.3 mg/kg, including 9/69 patients (13%) with NEC/NET. Rova-T at 0.3 mg/kg q6w had manageable toxicity, with antitumor activity observed in patients with NEC/NET, melanoma, MTC, and glioblastoma.

Updated Integrated Analysis of the Efficacy and Safety of Entrectinib in Locally Advanced or Metastatic ROS1 Fusion-Positive Non-Small-Cell Lung Cancer

Genetic rearrangements of the tyrosine receptor kinase ROS proto-oncogene 1 (ROS1) are oncogenic drivers in non-small-cell lung cancer (NSCLC). We report the results of an updated integrated analysis of three phase I or II clinical trials (ALKA-372-001, STARTRK-1, and STARTRK-2) of the ROS1 tyrosine kinase inhibitor, entrectinib, in ROS1 fusion–positive NSCLC.

Molecular Characterization and Therapeutic Targeting of Colorectal Cancers Harboring Receptor Tyrosine Kinase Fusions

PURPOSE

Receptor tyrosine kinase fusions in colorectal cancers are rare, but potentially therapeutically relevant. We describe clinical, molecular, and pathologic attributes of RTK fusion-associated colorectal cancer.

EXPERIMENTAL DESIGN

We identified all cases with RTK fusions in patients with colorectal cancer seen at Dana-Farber Cancer Institute (Boston, MA) who underwent OncoPanel testing between 2013 and 2018. Clinical, histologic, and molecular features were extracted from the patient charts and molecular testing results.

RESULTS

We identified 12 driver oncogenic fusions in various RTKs. These fusions occurred exclusively in BRAF and RAS wild-type tumors and were enriched in right-sided and mismatch repair-deficient (MMR-D) colorectal cancers. All of the MMR-D colorectal cancers with RTK fusions were found in tumors with acquired MMR-D due to MLH1 promoter hypermethylation and one was associated with a sessile serrated polyp. Molecular profiles of MMR-D colorectal cancer with RTK fusions largely resembled BRAF V600E-mutated MMR-D colorectal cancer, rather than those secondary to Lynch syndrome. We describe two patients with fusion-associated microsatellite stable (MSS) colorectal cancer who derived clinical benefit from therapeutic targeting of their translocation. The first harbored an ALK-CAD fusion and received sequential crizotinib and alectinib therapy for a total of 7.5 months until developing an ALK L1196Q gatekeeper mutation. The second patient, whose tumor contained an ROS1-GOPC fusion, continues to benefit from entrectinib after 9 months of therapy.

CONCLUSIONS

RTK fusions in colorectal cancer are a rare, but important disease subgroup that occurs in RAS and BRAF wild-type tumors. Despite enrichment in acquired MMR-D tumors, RTK fusions also occur in MSS colorectal cancer and provide an important therapeutic target.

CTNI-04. ACTIVITY OF LAROTRECTINIB IN TROPOMYOSIN RECEPTOR KINASE (TRK) FUSION CANCER PATIENTS WITH CENTRAL NERVOUS SYSTEM (CNS) METASTASES

BACKGROUND

NTRK gene fusions occur in a range of tumor types, including those with CNS metastases. Larotrectinib, a highly selective FDA- and EMA- approved TRK inhibitor, demonstrated an objective response rate (ORR) of 79% across various cancers (Hong et al. Lancet Oncol. 2020). We report data on patients with TRK fusion cancer with CNS metastases treated with larotrectinib.

METHODS

Patients with solid tumors with CNS metastases at baseline harboring an NTRK gene fusion enrolled in two clinical trials (NCT02122913 and NCT02576431) were identified. Response was assessed by the investigator per RECIST v1.1.

RESULTS

As of July 15, 2019, 14 patients with CNS-metastases were enrolled: lung cancer (n=7), thyroid cancer (n=4), melanoma (n=2), and non-secretory breast cancer (n=1). Median age was 53 years (range 25–76). Including all sites of disease, the ORR was 71% (95% CI 42–92%): ten patients had a partial response (PR), two had stable disease (SD), and two had progressive disease (lung and melanoma). Of the three patients with measurable intracranial disease at baseline, the best intracranial response was 1 complete response, 1 PR, and 1 SD. Median duration of response for all patients was 14.8 months (range 1.9+ to 17.4+), median progression-free survival was 9.9 months (range 1.4 to 19.3+), and median overall survival was 27.8 months (range 1.4+ to 27.8). Treatment duration ranged from 1.4 to 25.0 months; six patients continued treatment beyond progression (lasting between 0.1+ and 8.5 months). Treatment-emergent adverse events (TEAEs) were mainly Grade 1 and 2; Grade 3 TEAEs occurred in seven patients (50%), with one (myalgia) attributed to larotrectinib (7%). There were no Grade 4 TEAEs.

CONCLUSIONS

Larotrectinib was highly active and well tolerated in TRK fusion cancer patients with CNS metastases. These results support testing for NTRK gene fusions across all cancers, including in patients with CNS metastases.

Abstract CT199: Larotrectinib in TRK fusion cancer patients: Outcomes by prior therapy and performance status

Introduction: Larotrectinib, a highly selective Food and Drug Administration- and European Medicines Agency-approved TRK inhibitor, achieved an objective response rate (ORR) of 79% and a median duration of response (DoR) of 35.2 months across various cancers (Hong et al. Lancet Oncol. In press). In this data set, outcomes by the number of lines of prior therapy or baseline performance status have not previously been reported.

Methods: Data were pooled from three clinical trials of patients with TRK fusion cancer treated with larotrectinib (NCT02122913, NCT02576431, NCT02637687). Patients were stratified based on the number of lines of prior therapy (0, 1, 2, or ≥3) and baseline Eastern Cooperative Oncology Group (ECOG) performance status (0, 1, 2, or 3). A post hoc analysis of ORR, assessed by investigators using Response Evaluation Criteria in Solid Tumors 1.1, DoR, progression-free survival (PFS), and overall survival (OS) was performed (data cut-off was February 19, 2019).

Results: A total of 159 patients were enrolled. Stratified efficacy outcomes are shown in the table. The incidence of Grade 3/4 adverse events was similar across lines of therapy.

Number of prior lines of therapy012≥3Total(n=35)(n=48)(n=34)(n=42)(N=159)ORR, % (95% CI)91 (76, 98)70 (54, 82)73 (54, 87)85 (70, 94)79 (72, 85)DoRNENENE35.235.2(19.8, NE)(15.0, NE)(7.6, NE)(22.8, NE)(22.8, NE)1.9+, 37.1+1.6+, 40.2+1.9+, 44.2+1.9+, 38.2+1.6+, 44.2+PFS25.8NENE28.328.3(15.2, NE)(9.9, NE)(7.0, NE)(16.6, NE)(22.1, NE)0.03+, 38.8+0.03+, 42.1+0.03+, 45.2+0.03+, 40.0+0.03+, 45.2+OSNENE36.544.444.4(NE, NE)(33.4, NE)(36.5, NE)(NE, NE)(36.5, NE)0.03+, 39.9+0.5+, 43.1+0.3+, 47.2+1.0+, 44.40.03+, 47.2+ECOG performance status0123Total(n=76)(n=61)(n=19)(n=3)(N=159)ORR, % (95% CI)91 (81, 96)69 (56, 81)71 (44, 90)33 (1, 91)79 (72, 85)DoR35.226.3NENE35.2(22.8, NE)(19.8, NE)(7.2, NE)(22.8, NE)1.8+, 40.2+1.6+, 44.2+1.9+, 29.5+1.6+, 44.2+PFS36.825.8NENE28.3(24.6, NE)(9.0, NE)(2.7, NE)(1.1, NE)(22.1, NE)0.03+, 42.1+0.03+, 45.2+0.03+, 30.4+0.03+, 1.7+0.03+, 45.2+All data values show median (95% CI) and range in months, unless otherwise stated. CI, confidence interval; DoR, duration of response; ECOG, Eastern Cooperative Oncology Group; NE, not estimable; ORR, objective response rate; OS, overall survival; PFS, progression-free survival.

Conclusion: While response rates were highest in patients who were treatment-naïve or with an ECOG performance status of 0, larotrectinib benefited patients across varying degrees of pre-treatment or performance status.

Citation Format: Alexander Drilon, Cornelis M. van Tilburg, Anna F. Farago, Shivaani Kummar, Jordan Berlin, Catherine M. Albert, Ray McDermott, Ulrik N. Lassen, John A. Reeves, Nicoletta Brega, Barrett H. Childs, Theodore W. Laetsch, David S. Hong. Larotrectinib in TRK fusion cancer patients: Outcomes by prior therapy and performance status [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT199.

Abstract CT062: Efficacy and safety of larotrectinib in patients with cancer and NTRK gene fusions or other alterations

Introduction: A variety of alterations in NTRK genes have been identified in various cancers, including amplifications, rearrangements, deletions, splice variants as well as fusions. Larotrectinib is a highly selective TRK inhibitor that is active in patients (pts) with TRK fusion cancer. Here, we report post hoc efficacy and safety outcomes of larotrectinib treatment in pts with cancer and NTRK gene fusions (Fusion) vs those with Non-fusion alterations. Methods: Data were pooled from three clinical trials of adult and pediatric pts with TRK fusion cancer treated with larotrectinib (NCT02122913, NCT02576431, NCT02637687). NTRK gene status was assessed using local molecular testing; two studies (NCT02122913 and NCT02637687) initially enrolled pts regardless of TRK fusion status. Efficacy outcomes included objective response rate (ORR), assessed by investigators using RECIST 1.1, duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Adverse events (AEs) were also assessed. The data cut-off was February 19, 2019. Results: This analysis included 159 pts (153 evaluable for efficacy) with NTRK fusions, with 17 different tumor types, and 73 Non-fusion pts with various genomic alterations, with 25 different tumor types. NTRK alterations reported in the Non-fusion pts included point mutations in 8 pts, amplifications in 7, rearrangements in 4 and deletions in 1. The ORR was 79% (95% confidence interval [CI] 72-85) in the Fusion group, with complete responses (CR) in 24 (16%), partial responses (PR) in 97 (63%), stable disease (SD) in 19 (12%), and progressive disease (PD) in 9 (6%). Median DOR was 35.2 months (95% CI 22.8-not estimable [NE]). In the Non-fusion group treated with larotrectinib, there were no responses except for one pt with NTRK1 amplification who had a PR of short duration (3.7 months); 17 Non-fusion pts (23%) had SD and 48 (66%) had PD as best response. Similarly, differences were seen in survival endpoints between pts in the overall Fusion and Non-fusion groups: median PFS 28.3 mo vs 1.8 mo and median OS 44.4 mo vs 10.7 mo, respectively. Median time of treatment was 7.9 months in the Fusion group and 1.7 months in the Non-fusion group. Incidences of Grade 3 or 4 AEs were lower in the Fusion group (49%) vs the Non-fusion group (58%). Discontinuation due to AEs occurred in 6% of pts in the Fusion group vs 25% in the Non-fusion group. Conclusion: Larotrectinib is highly efficacious in pts with TRK fusion cancer and has demonstrated durable responses. Pts with other NTRK alterations, including point mutations and amplifications, had only limited benefit from larotrectinib.

Citation Format: David S. Hong, Afshin Dowlati, Howard Burris, Edward Chu, Marcia S. Brose, Anna F. Farago, Cornelis M. van Tilburg, Shivaani Kummar, Leo Mascarenhas, John A. Reeves, Marion Rudolph, Patricia Maeda, Barrett H. Childs, Theodore W. Laetsch, Alexander Drilon. Efficacy and safety of larotrectinib in patients with cancer and NTRK gene fusions or other alterations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT062.

Efficacy and safety of entrectinib in patients (pts) with NTRK-fusion positive (NTRK-fp) solid tumors: An updated integrated analysis

3605

Background: NTRK gene fusions lead to transcription of chimeric TRK proteins with overexpressed kinase function. Entrectinib is a potent inhibitor of TRKA/B/C. In phase 1/2 studies (ALKA, STARTRK-1, STARTRK-2; EudraCT 2012-000148-88; NCT02097810; NCT02568267), entrectinib was effective in pts with NTRK-fp solid tumors. We present updated data in a larger population with longer follow-up. Methods: In this integrated analysis of adult pts from 3 phase 1/2 trials (data cut-off 31 Oct 2018), tumors were assessed by blinded independent central review (BICR) with RECIST v1.1 (end of cycle 1; then every 8 wks). Primary endpoints were overall response rate (ORR) and duration of response (DOR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), efficacy in pts with/without baseline CNS disease, and safety. Results: There were 74 evaluable pts with advanced/metastatic NTRK-fp solid tumors (Table). Median duration of survival follow-up in all pts was 14.2 mo (range 0.1–29.7). BICR ORR was 63.5% (95% CI 51.5–74.4), with 5 complete responses (6.8%). Median BICR DOR was 12.9 mo (95% CI 9.3–NE); median BICR PFS was 11.2 mo (95% CI 8.0–15.7); median OS was 23.9 mo (16.0–NE). In pts with no baseline CNS disease (investigator-assessed; n=55), BICR ORR was 65.5% (95% CI 51.4–77.8) and median BICR DOR in responders was 12.9 mo (95% CI 9.3–NE). In pts with baseline CNS disease (investigator-assessed; n=19), BICR ORR was 57.9% (95% CI 33.5–79.8) and median BICR DOR in responders was 6.0 mo (95% CI 4.2–NE). Safety was in line with that previously reported; the most common ≥grade 3 treatment-related AEs were weight gain (8, 7.1%), anemia (8, 7.1%), and fatigue (7, 6.2%). Conclusions: In this updated analysis, including more pts and longer follow-up, entrectinib continued to demonstrate clinically meaningful responses in pts with NTRK-fp solid tumors, with and without baseline CNS disease. Clinical trial information: NCT02097810, NCT02568267 . [Table: see text]

Quality of life of adults and children with TRK fusion cancer treated with larotrectinib compared to the general population

3614

Background: NTRK gene fusions occur in diverse tumor types in adults and children. The selective TRK inhibitor, larotrectinib, has shown high response rates, durable disease control, and a favorable safety profile in patients (pts) with TRK fusion cancer. We report an expanded quality of life (QoL) analysis for pts treated with larotrectinib. Methods: QoL data were collected in two trials of larotrectinib in pts with TRK fusion cancer using EORTC QLQ-C30 (adults) and PedsQL (children) questionnaires, and were analyzed descriptively and longitudinally. EORTC QLQ-C30 global health scores (GHS) and PedsQL total scores range from 0 to 100, with higher scores indicating better QoL. We calculated the proportion of pts with normal/above and below normal QoL scores compared to values in the literature for the US general population. Results: By July 2019, 126 pts with TRK fusion cancer (74 adults, 24 children ≥2 yrs, and 28 infants <2 yrs) had received larotrectinib and completed baseline (BL) and ≥1 post-BL questionnaire. Most pts had clinically meaningful QoL improvements that reached or exceeded the minimally important difference (Table); a positive change from BL was also seen in infants: mean best change of 12.0 (SD 13.8). Of 52 adults with BL EORTC QLQ-C30 GHS at or above the population norm, 51 remained in this category on treatment and 1 moved into the below normal category. Of 22 adults with BL scores below the population norm, 20 moved into the normal/above normal category. All 9 children aged ≥2 yrs with BL PedsQL scores at or above the population norm remained in this category on treatment. Of 15 children with BL scores below the population norm, 10 moved into the normal/above normal category. Sustained QoL improvements (change from BL ≥0) occurred by 2 months of treatment in 69% of adults and 75% of children. Median duration of sustained improvement in EORTC QLQ-C30 GHS and PedsQL total score was 12.0 months (range 1.7–20.3) and not estimable (range 1.1–23.0), respectively. Conclusions: Adults and children with TRK fusion cancer treated with larotrectinib had rapid, clinically meaningful, and sustained improvements in QoL. Clinical trial information: NCT02576431, NCT02637687 . [Table: see text]

Activity and safety of larotrectinib in adult patients with TRK fusion cancer: An expanded data set

3610

Background: The highly selective TRK inhibitor larotrectinib is approved for the treatment of adult and pediatric cancers that harbor NTRK gene fusions; it achieves a 79% overall response rate (ORR) in this population (Hong et al., Lancet Oncol, 2020). The activity of larotrectinib in adults alone was further characterized in this update with a larger series of patients and more mature durability data. Methods: Adults (aged ≥18 y) with TRK fusion cancer treated in three larotrectinib clinical trials (NCT02122913, NCT02576431, and NCT02637687) were analyzed. Larotrectinib was administered 100 mg BID until disease progression, withdrawal, or unacceptable toxicity. ORR was investigator-assessed (RECIST v1.1). Compared to previously presented data on 74 patients, this expanded data set includes an additional 42 patients (data cutoff: July 15, 2019). Results: 116 adults (median age: 56 y, range 19–84 y; 53% female) with TRK fusion cancer were treated. Tumor types included thyroid cancer (22%), salivary gland cancer (19%), soft tissue sarcoma (16%), lung cancer (12%), colon cancer (7%), melanoma (5%), breast cancer (5%), GIST (3%), and 9 other types (≤2% each). NTRK fusions involved NTRK1 (43%), NTRK2 (3%), and NTRK3 (54%). 78% of patients had received prior systemic therapy (with 68% of those receiving ≥2 prior therapies). The ORR was 71% (95% CI 62–79): 10% complete response, 60% partial response (2% pending confirmation), 16% stable disease, 9% progressive disease, 3% not determined. In patients with brain metastases, the ORR was 71% (95% CI 42–92; 10 of 14 patients, all partial responses). Median duration of response for the overall data set (n = 116) was 35.2 mo (95% CI 21.6–not estimable [NE]). Median progression-free survival was 25.8 mo (95% CI 15.2–NE). Median overall survival was not reached (range 0.5+ to 51.6+ mo) at a median follow-up of 15.8 mo. Duration of treatment ranged from 0.10 to 51.6+ mo. 12% of patients had dose reductions. One patient (1%) discontinued due to a larotrectinib-related adverse event (AE). AEs were mostly grade 1–2; no new unexpected AEs were reported. Conclusions: In an expanded data set of adults with TRK fusion cancer, larotrectinib demonstrated robust and durable tumor-agnostic efficacy and favorable safety, supporting NTRK gene fusion testing in patients with solid tumors of any type. Clinical trial information: NTC02122913, NCT02576431, NCT02637687 .

A phase I/II study of rovalpituzumab tesirine in delta-like 3-expressing, advanced solid tumors

3552

Background: Delta-like 3 (DLL3) is highly and specifically expressed in solid tumors, such as neuroendocrine carcinomas (NECs), malignant melanoma (MM), and medullary thyroid carcinoma (MTC). Rovalpituzumab tesirine (Rova-T) is a DLL3-targeting antibody-drug conjugate. Methods: This Phase 1/2 study (NCT02709889) enrolled patients with relapsed/refractory DLL3+ (>1% by IHC) advanced solid tumors and ECOG performance status of 0-1. Rova-T was given IV at 0.2, 0.3, or 0.4 mg/kg on d 1 of each 6-wk cycle (q6wk) for dose escalation (3+3 design) in disease-specific cohorts in Phase I. The recommended Phase 2 dose (RP2D) was tested in Phase II. Safety and dose-limiting toxicities (DLTs) were primary endpoints; efficacy outcomes were secondary endpoints. Results: The study enrolled 200 patients; 101 had NECs (large cell NEC [n=13], neuroendocrine prostate cancer [n=21], high-grade gastroenteropancreatic NEC [n=36], other [n=31]) and 99 had other solid tumors (MM [n=20], MTC [n=13], glioblastoma [GBM; n=23], other [n=43]). The median age was 61 y (range, 28-84); 63% were male. The RP2D was 0.3 mg/kg q6wk for 2 cycles in all cohorts. There were 7 DLTs in 5 patients: 2 with 0.2 mg/kg (Grade [Gr] 3 photosensitivity reaction, Gr 3 dyspnea), 2 with 0.3 mg/kg (1 with Gr 2 effusion, Gr 3 tumor lysis syndrome, and Gr 3 rhabdomyolysis; 1 with Gr 4 kidney injury), and 1 with 0.4 mg/kg (Gr 4 thrombocytopenia). Despite only 1 DLT identified with 0.4 mg/kg, the totality of the safety data suggested that this dose is not well tolerated. Common adverse events (AEs) in patients given 0.3 mg/kg (n=145) are shown (Table). Serious AEs occurred in 77/145 patients (53%), most commonly (≥3%) malignant neoplasm progression (n=18; 12%), pleural effusion (n=7; 5%), pericardial effusion (n=6; 4%), and dyspnea (n=5; 3%). The objective response rate (ORR) was 11% (21/200): 14 had NEC, 2 had MM, 2 had MTC, 2 had small cell carcinoma (SCC) not of lung origin (all partial responses), and 1 had GBM (complete response). In patients with NECs given 0.3 mg/kg, ORR, clinical benefit rate, and progression-free survival trended in favor of those with high DLL3-expressing tumors (≥50% by IHC) which represented 51% of NECs. Conclusions: Rova-T was tolerable in patients with advanced solid tumors at 0.3 mg/kg q6wk for 2 cycles. Antitumor activity was observed in patients with NEC, MM, MTC, SCC, and GBM. Clinical trial information: NCT02709889 . [Table: see text]

New Approaches to SCLC Therapy: From the Laboratory to the Clinic

The outcomes of patients with SCLC have not yet been substantially impacted by the revolution in precision oncology, primarily owing to a paucity of genetic alterations in actionable driver oncogenes. Nevertheless, systemic therapies that include immunotherapy are beginning to show promise in the clinic. Although, these results are encouraging, many patients do not respond to, or rapidly recur after, current regimens, necessitating alternative or complementary therapeutic strategies. In this review, we discuss ongoing investigations into the pathobiology of this recalcitrant cancer and the therapeutic vulnerabilities that are exposed by the disease state. Included within this discussion, is a snapshot of the current biomarker and clinical trial landscapes for SCLC. Finally, we identify key knowledge gaps that should be addressed to advance the field in pursuit of reduced SCLC mortality. This review largely summarizes work presented at the Third Biennial International Association for the Study of Lung Cancer SCLC Meeting.

Larotrectinib, a selective tropomyosin receptor kinase inhibitor for adult and pediatric tropomyosin receptor kinase fusion cancers

Gene fusions involving NTRK1, NTRK2 and NTRK3 are oncogenic drivers across a wide variety of cancer types. Inhibitors of the chimeric TRKA/B/C protein kinases encoded by these fusions are now available, including larotrectinib, a potent and highly selective oral drug. Integrated data from three trials demonstrate substantial clinical activity of larotrectinib in patients with many different types of cancers harboring NTRK fusions. Larotrectinib has received accelerated approval from both the US FDA and the EMA. Resistance mutations have been observed in the kinase domains of the NTRK fusion genes and development of next-generation tropomyosin receptor kinase inhibitors designed to overcome such resistance mutations is being actively pursued in clinical trials and ongoing drug discovery efforts.

Larotrectinib in patients with TRK fusion-positive solid tumours: a pooled analysis of three phase 1/2 clinical trials

BACKGROUND

The selective TRK inhibitor larotrectinib was approved for paediatric and adult patients with advanced TRK fusion-positive solid tumours based on a primary analysis set of 55 patients. The aim of our analysis was to explore the efficacy and long-term safety of larotrectinib in a larger population of patients with TRK fusion-positive solid tumours.

METHODS

Patients were enrolled and treated in a phase 1 adult, a phase 1/2 paediatric, or a phase 2 adolescent and adult trial. Some eligibility criteria differed between these studies. For this pooled analysis, eligible patients were aged 1 month or older, with a locally advanced or metastatic non-CNS primary, TRK fusion-positive solid tumour, who had received standard therapy previously if available. This analysis set includes the 55 patients on which approval of larotrectinib was based. Larotrectinib was administered orally (capsule or liquid formulation), on a continuous 28-day schedule, to adults mostly at a dose of 100 mg twice daily, and to paediatric patients mostly at a dose of 100 mg/m² (maximum of 100 mg) twice daily. The primary endpoint was objective response as assessed by local investigators in an intention-to-treat analysis. Contributing trials are registered with ClinicalTrials.gov, NCT02122913 (active not recruiting), NCT02637687 (recruiting), and NCT02576431 (recruiting).

FINDINGS

Between May 1, 2014, and Feb 19, 2019, 159 patients with TRK fusion-positive cancer were enrolled and treated with larotrectinib. Ages ranged from less than 1 month to 84 years. The proportion of patients with an objective response according to investigator assessment was 121 (79%, 95% CI 72-85) of 153 evaluable patients, with 24 (16%) having complete responses. In a safety population of 260 patients treated regardless of TRK fusion status, the most common grade 3 or 4 larotrectinib-related adverse events were increased alanine aminotransferase (eight [3%] of 260 patients), anaemia (six, 2%), and decreased neutrophil count (five [2%]). The most common larotrectinib-related serious adverse events were increased alanine aminotransferase (two [<1%] of 260 patients), increased aspartate aminotransferase (two [<1%]), and nausea (two [<1%]). No treatment-related deaths occurred.

INTERPRETATION

These data confirm that TRK fusions define a unique molecular subgroup of advanced solid tumours for which larotrectinib is highly active. Safety data indicate that long-term administration of larotrectinib is feasible.

FUNDING

Bayer and Loxo Oncology.

Entrectinib in patients with advanced or metastatic NTRK fusion-positive solid tumours: integrated analysis of three phase 1-2 trials

BACKGROUND

Entrectinib is a potent inhibitor of tropomyosin receptor kinase (TRK) A, B, and C, which has been shown to have anti-tumour activity against NTRK gene fusion-positive solid tumours, including CNS activity due to its ability to penetrate the blood-brain barrier. We present an integrated efficacy and safety analysis of patients with metastatic or locally advanced solid tumours harbouring oncogenic NTRK1, NTRK2, and NTRK3 gene fusions treated in three ongoing, early-phase trials.

METHODS

An integrated database comprised the pivotal datasets of three, ongoing phase 1 or 2 clinical trials (ALKA-372-001, STARTRK-1, and STARTRK-2), which enrolled patients aged 18 years or older with metastatic or locally advanced NTRK fusion-positive solid tumours who received entrectinib orally at a dose of at least 600 mg once per day in a capsule. All patients had an Eastern Cooperative Oncology Group performance status of 0-2 and could have received previous anti-cancer therapy (except previous TRK inhibitors). The primary endpoints, the proportion of patients with an objective response and median duration of response, were evaluated by blinded independent central review in the efficacy-evaluable population (ie, patients with NTRK fusion-positive solid tumours who were TRK inhibitor-naive and had received at least one dose of entrectinib). Overall safety evaluable population included patients from STARTRK-1, STARTRK-2, ALKA-372-001, and STARTRK-NG (NCT02650401; treating young adult and paediatric patients [aged ≤21 years]), who received at least one dose of entrectinib, regardless of tumour type or gene rearrangement. NTRK fusion-positive safety evaluable population comprised all patients who have received at least one dose of entrectinib regardless of dose or follow-up. These ongoing studies are registered with ClinicalTrials.gov, NCT02097810 (STARTRK-1) and NCT02568267 (STARTRK-2), and EudraCT, 2012-000148-88 (ALKA-372-001).

FINDINGS

Patients were enrolled in ALKA-372-001 from Oct 26, 2012, to March 27, 2018; in STARTRK-1 from Aug 7, 2014, to May 10, 2018; and in STARTRK-2 from Nov 19, 2015 (enrolment is ongoing). At the data cutoff date for this analysis (May 31, 2018) the efficacy-evaluable population comprised 54 adults with advanced or metastatic NTRK fusion-positive solid tumours comprising ten different tumour types and 19 different histologies. Median follow-up was 12.9 months (IQR 8·77-18·76). 31 (57%; 95% CI 43·2-70·8) of 54 patients had an objective response, of which four (7%) were complete responses and 27 (50%) partial reponses. Median duration of response was 10 months (95% CI 7·1 to not estimable). The most common grade 3 or 4 treatment-related adverse events in both safety populations were increased weight (seven [10%] of 68 patients in the NTRK fusion-positive safety population and in 18 [5%] of 355 patients in the overall safety-evaluable population) and anaemia (8 [12%] and 16 [5%]). The most common serious treatment-related adverse events were nervous system disorders (three [4%] of 68 patients and ten [3%] of 355 patients). No treatment-related deaths occurred.

INTERPRETATION

Entrectinib induced durable and clinically meaningful responses in patients with NTRK fusion-positive solid tumours, and was well tolerated with a manageable safety profile. These results show that entrectinib is a safe and active treatment option for patients with NTRK fusion-positive solid tumours. These data highlight the need to routinely test for NTRK fusions to broaden the therapeutic options available for patients with NTRK fusion-positive solid tumours.

FUNDING

Ignyta/F Hoffmann-La Roche.

Identification of DHODH as a therapeutic target in small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive lung cancer subtype with extremely poor prognosis. No targetable genetic driver events have been identified, and the treatment landscape for this disease has remained nearly unchanged for over 30 years. Here, we have taken a CRISPR-based screening approach to identify genetic vulnerabilities in SCLC that may serve as potential therapeutic targets. We used a single-guide RNA (sgRNA) library targeting ~5000 genes deemed to encode "druggable" proteins to perform loss-of-function genetic screens in a panel of cell lines derived from autochthonous genetically engineered mouse models (GEMMs) of SCLC, lung adenocarcinoma (LUAD), and pancreatic ductal adenocarcinoma (PDAC). Cross-cancer analyses allowed us to identify SCLC-selective vulnerabilities. In particular, we observed enhanced sensitivity of SCLC cells toward disruption of the pyrimidine biosynthesis pathway. Pharmacological inhibition of dihydroorotate dehydrogenase (DHODH), a key enzyme in this pathway, reduced the viability of SCLC cells in vitro and strongly suppressed SCLC tumor growth in human patient-derived xenograft (PDX) models and in an autochthonous mouse model. These results indicate that DHODH inhibition may be an approach to treat SCLC.

Combination Olaparib and Temozolomide in Relapsed Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive malignancy in which inhibitors of PARP have modest single-agent activity. We performed a phase I/II trial of combination olaparib tablets and temozolomide (OT) in patients with previously treated SCLC. We established a recommended phase II dose of olaparib 200 mg orally twice daily with temozolomide 75 mg/m² daily, both on days 1 to 7 of a 21-day cycle, and expanded to a total of 50 patients. The confirmed overall response rate was 41.7% (20/48 evaluable); median progression-free survival was 4.2 months [95% confidence interval (CI), 2.8-5.7]; and median overall survival was 8.5 months (95% CI, 5.1-11.3). Patient-derived xenografts (PDX) from trial patients recapitulated clinical OT responses, enabling a 32-PDX coclinical trial. This revealed a correlation between low basal expression of inflammatory-response genes and cross-resistance to both OT and standard first-line chemotherapy (etoposide/platinum). These results demonstrate a promising new therapeutic strategy in SCLC and uncover a molecular signature of those tumors most likely to respond. SIGNIFICANCE: We demonstrate substantial clinical activity of combination olaparib/temozolomide in relapsed SCLC, revealing a promising new therapeutic strategy for this highly recalcitrant malignancy. Through an integrated coclinical trial in PDXs, we then identify a molecular signature predictive of response to OT, and describe the common molecular features of cross-resistant SCLC.See related commentary by Pacheco and Byers, p. 1340.This article is highlighted in the In This Issue feature, p. 1325.

Efficacy and Safety of Rovalpituzumab Tesirine in Third-Line and Beyond Patients with DLL3-Expressing, Relapsed/Refractory Small-Cell Lung Cancer: Results From the Phase II TRINITY Study

PURPOSE

Although extensive-stage small-cell lung cancer (SCLC) is highly responsive to first-line therapy, virtually all patients develop resistance with short survival. Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate targeting delta-like 3 protein (DLL3). This open-label, single-arm, phase II study (TRINITY) assessed safety and efficacy of Rova-T in patients with DLL3-expressing SCLC in the third-line and beyond (3L+) setting.

PATIENTS AND METHODS

Patients with DLL3-expressing SCLC (determined by mouse antibody immunohistochemistry [IHC] assay), and ≥2 prior regimens, received 0.3 mg/kg Rova-T once every 6 weeks for two cycles. During study, a rabbit antibody IHC assay was developed and used for the final analysis, with DLL3-positive and DLL3-high defined as ≥25% and ≥75% of tumor cells positive for DLL3, respectively. The primary endpoints were objective response rate (ORR) and overall survival (OS).

RESULTS

Among 339 patients enrolled, 261 (77%) had two prior lines of therapy and 78 (23%) had ≥3. DLL3-high and DLL3-positive tumors by rabbit IHC were seen in 238 (70%) and 287 (85%) patients, respectively. The remaining 52 (15%) were DLL3-negative only by rabbit IHC or had missing results. ORR was 12.4%, 14.3%, and 13.2% in all, DLL3-high, and DLL3-positive patients, respectively. Median OS was 5.6 months in all patients and 5.7 months in DLL3-high patients. The most common adverse events (AE) were fatigue, photosensitivity reaction, and pleural effusion. Grade 3-5 AEs were seen in 213 (63%) patients.

CONCLUSIONS

Rova-T is the first targeted agent in SCLC to use DLL3, a novel biomarker. However, results demonstrate modest clinical activity in 3L+ SCLC, with associated toxicities.

Treatment with Next-Generation ALK Inhibitors Fuels Plasma ALK Mutation Diversity

PURPOSE

Acquired resistance to next-generation ALK tyrosine kinase inhibitors (TKIs) is often driven by secondary ALK mutations. Here, we investigated utility of plasma genotyping for identifying ALK resistance mutations at relapse on next-generation ALK TKIs.

EXPERIMENTAL DESIGN

We analyzed 106 plasma specimens from 84 patients with advanced ALK-positive lung cancer treated with second- and third-generation ALK TKIs using a commercially available next-generation sequencing (NGS) platform (Guardant360). Tumor biopsies from TKI-resistant lesions underwent targeted NGS to identify ALK mutations.

RESULTS

By genotyping plasma, we detected an ALK mutation in 46 (66%) of 70 patients relapsing on a second-generation ALK TKI. When post-alectinib plasma and tumor specimens were compared, there was no difference in frequency of ALK mutations (67% vs. 63%), but plasma specimens were more likely to harbor ≥2 ALK mutations (24% vs. 2%, P = 0.004). Among 29 patients relapsing on lorlatinib, plasma genotyping detected an ALK mutation in 22 (76%), including 14 (48%) with ≥2 ALK mutations. The most frequent combinations of ALK mutations were G1202R/L1196M and D1203N/1171N. Detection of ≥2 ALK mutations was significantly more common in patients relapsing on lorlatinib compared with second-generation ALK TKIs (48% vs. 23%, P = 0.017). Among 15 patients who received lorlatinib after a second-generation TKI, serial plasma analysis demonstrated that eight (53%) acquired ≥1 new ALK mutations on lorlatinib.

CONCLUSIONS

ALK resistance mutations increase with each successive generation of ALK TKI and may be underestimated by tumor genotyping. Sequential treatment with increasingly potent ALK TKIs may promote acquisition of ALK resistance mutations leading to treatment-refractory compound ALK mutations.

Abstract CT131: Entrectinib in NTRK-fusion positive (NTRK-FP) non-small cell lung cancer (NSCLC): Integrated analysis of patients enrolled in three trials (STARTRK-2, STARTRK-1 and ALKA-372-001)

Background Gene fusions involving NTRK (neurotrophic receptor tyrosine kinase) genes result in the expression of chimeric TRK proteins with uncontrolled kinase activity, leading to oncogenic transformation and unrestrained cancer cell proliferation, which confers oncogenic potential across many histopathologies. Entrectinib is a central nervous system (CNS)-active, potent inhibitor of all TRK kinases, as well as ROS1. We present integrated efficacy and safety data for entrectinib in patients with locally advanced/metastatic NTRK fusion-positive (NTRK-FP) solid tumors enrolled in global (&gt;150 sites, 15 countries) Phase I/II entrectinib trials (ALKA-372-001 [EudraCT 2012-000148-88], STARTRK-1 [NCT02097810], STARTRK-2 [NCT02568267]), focusing on a cohort of patients with NSCLC.

Methods The analysis included patients with TRK inhibitor-naïve solid tumors (with or without baseline CNS disease) harboring an NTRK fusion identified via nucleic acid-based diagnostic platforms. Tumor assessments were performed at week 4 and every 8 weeks thereafter. Disease burden was assessed per blinded independent central review (BICR) by RECIST v1.1. Primary endpoints (per BICR): overall response rate (ORR) and duration of response (DOR). Key secondary endpoints: progression-free survival (PFS), overall survival (OS) and safety

Results In the total efficacy-evaluable population (n=54 adult patients with advanced/metastatic NTRK-FP solid tumors, median age 57.5 years, 59.3% female, 22.2% baseline CNS disease, &gt;19 histopathologies across 10 cancer types), ORR (BICR) was 57.4% (95% CI 43.2-70.8), with 4 complete responses (7.4%); responses were seen in all tumor types. Median DOR: 10.4 months (95% CI 7.1-NR); median PFS: 11.2 months (95% CI 8.0-14.9); median OS: 20.9 months (95% CI 14.9-NR). In the cohort of patients with NTRK-FP NSCLC (n=10), ORR (BICR) was 70.0% (7/10; 7/7 adenocarcinoma NSCLC, 0/3 squamous cell or unclassified/undifferentiated NSCLC). In NSCLC patients with investigator-assessed baseline CNS disease (n=6), 4/6 had an intracranial response (2 complete, 2 partial); 1 had stable disease, and 1 was not evaluable. In the safety population (68 patients with NTRK-FP solid tumors who received at least 1 dose of entrectinib) most treatment-related adverse events (AEs) were grade 1-2; grade 3: 32.4% of patients, grade 4: 2.9% of patients; no grade 5 treatment-related AEs. AEs resulted in dose reduction in 39.7% of patients and discontinuation in 4.4% of patients.

Conclusion In this integrated analysis of global multicenter clinical trials, entrectinib was well tolerated and induced clinically meaningful, durable systemic and CNS responses in patients with NTRK-FP solid tumors, including those with NSCLC.

Citation Format: Robert Doebele, Luis Paz-Ares, Anna F. Farago, Stephen V. Liu, Sant P. Chawla, Diego Tosi, Collin M. Blakely, John C. Krauss, Darren Sigal, Lyudmila Bazhenova, Tom John, Benjamin Besse, Jürgen Wolf, Takashi Seto, Edna Chow-Maneval, Chenglin Ye, Brian Simmons, George D. Demetri. Entrectinib in NTRK-fusion positive (NTRK-FP) non-small cell lung cancer (NSCLC): Integrated analysis of patients enrolled in three trials (STARTRK-2, STARTRK-1 and ALKA-372-001) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT131.

Larotrectinib efficacy and safety in adult TRK fusion cancer patients

3122

Background: A broad range of pediatric and adult malignancies harbor TRK fusions involving the NTRK1, NTRK2, and NTRK3 genes. The highly-selective TRK inhibitor, larotrectinib, has previously shown a high overall response rate (ORR) and a favorable safety profile in patients (pts) with TRK fusion cancer. To better delineate efficacy in adults, as pediatric pts have a particularly high ORR, here we report updated efficacy and safety data from the adult subset of pts with TRK fusion cancer treated with larotrectinib. Methods: Adult pts (aged 18 or older) with TRK fusion cancer detected by local testing in 2 larotrectinib clinical trials (NCT02122913 and NCT02576431) were analyzed. Larotrectinib was administered 100 mg PO BID until disease progression, withdrawal, or unacceptable toxicity. Disease status was assessed by both investigator (INV) and independent assessment (IRC) using RECIST v1.1. Results: As of July 30, 2018, 83 adults (median age: 57 y, range 20–80 y) with TRK fusion cancer had been treated. Cancer types included salivary gland (23%) and thyroid cancer (19%), soft tissue sarcoma (14%), lung cancer (13%), colon cancer and melanoma (7% each), GIST (5%), and bone sarcoma, cholangiocarcinoma, and appendiceal, breast, and pancreas cancer (≤2% each). TRK fusions involved NTRK1 (40%), NTRK2 (2%), and NTRK3 (57%). 77% of pts had received prior systemic therapy (median lines: 2, range 0–10). In 74 pts evaluable per INV, the ORR was 76% with 9% CR, 57% confirmed PR, 9% PR pending confirmation, 12% SD, 11% PD, and 1% not determined; 9 pts were non-evaluable (NE) due to lack of post-baseline assessment. In 65 pts evaluable per IRC, the ORR was 68% with 17% CR, 51% PR, 15% SD, 12% PD, and 5% NE. With a median follow up of 17.2 and 17.5 mo per INV and IRC, respectively, the median duration of response had not been reached (ranges identical: 1.9+ to 38.7+ months). At data cutoff, 63% remained on treatment; 30% had discontinued due to disease progression. Adverse events were mostly grade 1–2. Conclusions: Larotrectinib demonstrated robust tumor-agnostic efficacy and a favorable safety profile in adult pts with TRK fusion cancer. These results support testing for TRK fusion cancer in pts with advanced solid tumors, regardless of site of primary diagnosis. Clinical trial information: NCT02122913 and NCT02576431.

Activity of larotrectinib in TRK fusion cancer patients with brain metastases or primary central nervous system tumors

2006

Background: TRK fusions are oncogenic drivers of a variety of cancers, many of which can involve the central nervous system (CNS). Larotrectinib is an FDA-approved selective TRK inhibitor for the treatment of TRK fusion cancer (Drilon et al, NEJM 2018). While larotrectinib has been shown to cross the blood–brain barrier (Ziegler et al, Br J Cancer 2018), its clinical activity in a series of TRK fusion cancers with primary or metastatic intracranial disease has not been described. Methods: Patients (pts) with non-primary CNS solid tumors with brain metastases, or primary CNS tumors harboring a TRK fusion treated with larotrectinib in 2 clinical trials (NCT02637687, NCT02576431) were identified. Larotrectinib was administered until disease progression (PD), withdrawal, or unacceptable toxicity. Disease status was investigator-assessed (RANO and RECIST). Data cutoff: July 30, 2018. Results: 14 pts were identified: 5 non-primary CNS solid tumors (3 lung cancer, 2 thyroid cancer; fusion type: 2 ETV6-NTRK3, 2 SQSTM1-NTRK3, 1 EPS15-NTRK1; age range 25–79 y) and 9 primary CNS tumors (3 glioma, 2 glioblastoma, 1 astrocytoma, 3 NOS; fusion type: 3 BCR-NTRK2, 2 KANK-NTRK2, 1 each of AFAP1-NTRK1, AGTPBP1-NTRK2, ETV6-NTRK3, SPECC1L-NTRK2; age range 2–79 y). In the 5 pts with non-primary CNS tumors, the best objective response to therapy was PR in 3 (60%, 1 pending confirmation), SD in 1 (20%), and not evaluable (NE) in 1 (20%). Duration of response ranged from 9+ to 13 mo. In the 9 pts with primary CNS tumors, disease control was achieved in all evaluable pts (primary PD not observed; 1 pt required dose increase). The best objective response to therapy was PR in 1 (11%; pending confirmation, −55% tumor shrinkage, ongoing at 3.7 mo), SD in 7 (78%; tumor shrinkage range −1% to −24% for pts with measurable disease, 5 had SD > 4 mo), and NE in 1 (11%). Duration of treatment ranged from 2.8–9.2+ mo. Conclusions: Larotrectinib is active in pts with TRK fusion cancers with intracranial disease. Confirmed responses and durable disease control were seen in metastatic disease and primary CNS tumors of various histologies. These results further support expanded testing for TRK fusions across all cancers, including primary CNS tumors. Clinical trial information: NCT02637687 and NCT02576431.

Efficacy of entrectinib in patients (pts) with solid tumors and central nervous system (CNS) metastases: Integrated analysis from three clinical trials

3017

Background: Entrectinib potently inhibits kinases encoded by the NTRK and ROS1 genes. It achieves therapeutic levels in the CNS with antitumor activity in intracranial tumor models. We report integrated data (31 May 2018 cut-off) from 3 Phase 1/2 entrectinib trials (ALKA-372-001, EudraCT 2012-000148-88; STARTRK-1, NCT02097810; STARTRK-2, NCT02568267) for a large cohort of adults with ROS1 fusion-positive NSCLC ( ROS1+) or NTRK fusion-positive solid tumors ( NTRK+), with/without baseline CNS metastases. Methods: Pts had locally advanced/metastatic NTRK+ or ROS1+ tumors by nucleic acid-based confirmation. Baseline CNS metastases were identified by CT/MRI. Tumor assessments were at wk 4, then every 8 wk by blinded independent central review (RECIST v1.1). Primary endpoints: ORR, DOR. Secondary endpoints: CBR, PFS, OS, intracranial efficacy and safety. Results: Most pts had ≥1 prior therapy; 33% had baseline CNS metastases. Outcomes for the ROS1+ NSCLC (n = 53) and NTRK+ solid tumors (n = 54; 24% sarcoma, 18% NSCLC) efficacy evaluable data sets are shown (table). Entrectinib was tolerable with a manageable safety profile; most treatment-related AEs were grade 1–2. Conclusions: Entrectinib induced clinically meaningful durable responses in pts with ROS1+ NSCLC or NTRK+ solid tumors with or without CNS disease. Clinical trial information: NCT02097810; NCT02568267. [Table: see text]

EGFR-Mutant Adenocarcinomas That Transform to Small-Cell Lung Cancer and Other Neuroendocrine Carcinomas: Clinical Outcomes

PURPOSE

Approximately 3% to 10% of EGFR (epidermal growth factor receptor) -mutant non-small cell lung cancers (NSCLCs) undergo transformation to small-cell lung cancer (SCLC), but their clinical course is poorly characterized.

METHODS

We retrospectively identified patients with EGFR-mutant SCLC and other high-grade neuroendocrine carcinomas seen at our eight institutions. Demographics, disease features, and outcomes were analyzed.

RESULTS

We included 67 patients-38 women and 29 men; EGFR mutations included exon 19 deletion (69%), L858R (25%), and other (6%). At the initial lung cancer diagnosis, 58 patients had NSCLC and nine had de novo SCLC or mixed histology. All but these nine patients received one or more EGFR tyrosine kinase inhibitor before SCLC transformation. Median time to transformation was 17.8 months (95% CI, 14.3 to 26.2 months). After transformation, both platinum-etoposide and taxanes yielded high response rates, but none of 17 patients who received immunotherapy experienced a response. Median overall survival since diagnosis was 31.5 months (95% CI, 24.8 to 41.3 months), whereas median survival since the time of SCLC transformation was 10.9 months (95% CI, 8.0 to 13.7 months). Fifty-nine patients had tissue genotyping at first evidence of SCLC. All maintained their founder EGFR mutation, and 15 of 19 with prior EGFR T790M positivity were T790 wild-type at transformation. Other recurrent mutations included TP53, Rb1, and PIK3CA. Re-emergence of NSCLC clones was identified in some cases. CNS metastases were frequent after transformation.

CONCLUSION

There is a growing appreciation that EGFR-mutant NSCLCs can undergo SCLC transformation. We demonstrate that this occurs at an average of 17.8 months after diagnosis and cases are often characterized by Rb1, TP53, and PIK3CA mutations. Responses to platinum-etoposide and taxanes are frequent, but checkpoint inhibitors yielded no responses. Additional investigation is needed to better elucidate optimal strategies for this group.

Larotrectinib in adult patients with solid tumours: a multi-centre, open-label, phase I dose-escalation study

BACKGROUND

NTRK1, NTRK2 and NTRK3 gene fusions (NTRK gene fusions) occur in a range of adult cancers. Larotrectinib is a potent and highly selective ATP-competitive inhibitor of TRK kinases and has demonstrated activity in patients with tumours harbouring NTRK gene fusions.

PATIENTS AND METHODS

This multi-centre, phase I dose escalation study enrolled adults with metastatic solid tumours, regardless of NTRK gene fusion status. Key inclusion criteria included evaluable and/or measurable disease, Eastern Cooperative Oncology Group performance status 0-2, and adequate organ function. Larotrectinib was administered orally once or twice daily, on a continuous 28-day schedule, in increasing dose levels according to a standard 3 + 3 dose escalation scheme. The primary end point was the safety of larotrectinib, including dose-limiting toxicity.

RESULTS

Seventy patients (8 with tumours with NTRK gene fusions; 62 with tumours without a documented NTRK gene fusion) were enrolled to 6 dose cohorts. There were four dose-limiting toxicities; none led to study drug discontinuation. The maximum tolerated dose was not reached. Larotrectinib-related adverse events were predominantly grade 1; none were grade 4 or 5. The most common grade 3 larotrectinib-related adverse event was anaemia [4 (6%) of 70 patients]. A dose of 100 mg twice daily was recommended for phase II studies based on tolerability and antitumour activity. In patients with evaluable TRK fusion cancer, the objective response rate by independent review was 100% (eight of the eight patients). Eight (12%) of the 67 assessable patients overall had an objective response by investigator assessment. Median duration of response was not reached. Larotrectinib had limited activity in tumours with NTRK mutations or amplifications. Pharmacokinetic analysis showed exposure was generally proportional to administered dose.

CONCLUSIONS

Larotrectinib was well tolerated, demonstrated activity in all patients with tumours harbouring NTRK gene fusions, and represents a new treatment option for such patients.

CLINCALTRIALS.GOV NUMBER

NCT02122913.

Expediting Comprehensive Molecular Analysis to Optimize Initial Treatment of Lung Cancer Patients With Minimal Smoking History

INTRODUCTION

Lung cancer patients with tumors harboring actionable alterations can achieve very durable responses to first-line targeted therapy. However, identifying targetable alterations using next-generation sequencing (NGS) is a complex and time-intensive process. As actionable genetic alterations are enriched in lung cancers arising in patients with limited smoking history, we designed a workflow to expedite NGS testing for this group.

METHODS

We developed a protocol to allow for next-day extraction of nucleic acids from frozen tissue. Specimens were designated as high priority during sequencing. We determined the interval between biopsy and NGS results to evaluate whether the workflow reduced the pre-analytical period and in-laboratory turnaround time and allowed for rapid initiation of genotype-matched therapy.

RESULTS

Between January 2017 and May 2018, 21 patients participated in the expedited sequencing program. The median interval between biopsy and NGS results was 10.7 days. Six patients received results within 1 week of biopsy. Performing molecular analysis on frozen tissue and prioritizing sequencing and analysis of these specimens reduced the pre-analytical period from 3.5 to 1.3 days (p < 0.0001) and shortened in-laboratory turnaround time by 3 days (11.8 versus 8.4 business days, p < 0.0001). Ninety-three percent of patients with an actionable molecular alteration received first-line targeted therapy. The median time-to-initiation of treatment was 19.7 days from biopsy.

CONCLUSIONS

Sequencing and analyzing nucleic acids from frozen tissue is a practical strategy for shortening the time to matched therapy. The significant advantage of upfront treatment with targeted therapies in subsets of lung cancer patients provides rationale for developing workflows that accelerate comprehensive molecular analysis.

ATLANTIS: a Phase III study of lurbinectedin/doxorubicin versus topotecan or cyclophosphamide/doxorubicin/vincristine in patients with small-cell lung cancer who have failed one prior platinum-containing line

Lurbinectedin is an inhibitor of active transcription of protein-coding genes, causing DNA-break accumulation, apoptosis and modulation of the tumor microenvironment. Early-phase clinical trials indicate promising activity of lurbinectedin in small-cell lung cancer. Here, we describe the rationale and design of ATLANTIS (NCT02566993), an open-label, randomized, multicenter Phase III study to compare the efficacy of lurbinectedin and doxorubicin combination with standard-of-care chemotherapy, investigator's choice of cyclophosphamide/doxorubicin/vincristine or topotecan, in patients with small-cell lung cancer that has progressed following one line of platinum-based chemotherapy. Patients are randomized in a 1:1 ratio. The primary end point is overall survival and key secondary end points include progression-free survival, best tumor response and duration of response, each assessed by independent review committee.

Third-Line Nivolumab Monotherapy in Recurrent SCLC: CheckMate 032

Introduction:

For patients with recurrent SCLC, topotecan remains the only approved second-line treatment, and the outcomes are poor. CheckMate 032 is a phase 1/2, multicenter, open-label study of nivolumab or nivolumab plus ipilimumab in SCLC or other advanced/metastatic solid tumors previously treated with one or more platinum-based chemotherapies. We report results of third- or later-line nivolumab monotherapy treatment in SCLC.

Methods:

In this analysis, patients with limited-stage or extensive-stage SCLC and disease progression after two or more chemotherapy regimens received nivolumab monotherapy, 3 mg/kg every 2 weeks, until disease progression or unacceptable toxicity. The primary end point was objective response rate. Secondary end points included duration of response, progression-free survival, overall survival, and safety.

Results:

Between December 4, 2013, and November 30, 2016, 109 patients began receiving third- or later-line nivolumab monotherapy. At a median follow-up of 28.3 months (from first dose to database lock), the objective response rate was 11.9% (95% confidence interval: 6.5–19.5) with a median duration of response of 17.9 months (range 3.0–42.1). At 6 months, 17.2% of patients were progression-free. The 12-month and 18-month overall survival rates were 28.3% and 20.0%, respectively. Grade 3 to 4 treatment-related adverse events occurred in 11.9% of patients. Three patients (2.8%) discontinued because of treatment-related adverse events.

Conclusions:

Nivolumab monotherapy provided durable responses and was well tolerated as a third- or later-line treatment for recurrent SCLC. These results suggest that nivolumab monotherapy is an effective third- or later-line treatment for this patient population.

Exploiting MCL1 Dependency with Combination MEK + MCL1 Inhibitors Leads to Induction of Apoptosis and Tumor Regression in KRAS-Mutant Non-Small Cell Lung Cancer

BH3 mimetic drugs, which inhibit prosurvival BCL2 family proteins, have limited single-agent activity in solid tumor models. The potential of BH3 mimetics for these cancers may depend on their ability to potentiate the apoptotic response to chemotherapy and targeted therapies. Using a novel class of potent and selective MCL1 inhibitors, we demonstrate that concurrent MEK + MCL1 inhibition induces apoptosis and tumor regression in KRAS-mutant non-small cell lung cancer (NSCLC) models, which respond poorly to MEK inhibition alone. Susceptibility to BH3 mimetics that target either MCL1 or BCL-xL was determined by the differential binding of proapoptotic BCL2 proteins to MCL1 or BCL-xL, respectively. The efficacy of dual MEK + MCL1 blockade was augmented by prior transient exposure to BCL-xL inhibitors, which promotes the binding of proapoptotic BCL2 proteins to MCL1. This suggests a novel strategy for integrating BH3 mimetics that target different BCL2 family proteins for KRAS-mutant NSCLC. SIGNIFICANCE: Defining the molecular basis for MCL1 versus BCL-xL dependency will be essential for effective prioritization of BH3 mimetic combination therapies in the clinic. We discover a novel strategy for integrating BCL-xL and MCL1 inhibitors to drive and subsequently exploit apoptotic dependencies of KRAS-mutant NSCLCs treated with MEK inhibitors.See related commentary by Leber et al., p. 1511.This article is highlighted in the In This Issue feature, p. 1494.

Clinical Utility of Rapid EGFR Genotyping in Advanced Lung Cancer

PURPOSE

Targeted therapy is the cornerstone of treatment of advanced EGFR-mutant non-small-cell lung cancer (NSCLC). Next-generation sequencing (NGS), the preferred method for genotyping, typically requires several weeks. Here, we assessed workflows designed to rapidly identify patients with actionable EGFR mutations and reduce time to initiation (TTI) of epidermal growth factor receptor (EGFR)-directed therapy.

PATIENTS AND METHODS

We performed rapid testing for EGFR L858R mutations and exon 19 deletions on paraffin-embedded or frozen section biopsy specimens from newly diagnosed patients with metastatic NSCLC by using an EGFR-specific assay (rapid test). To determine clinical utility, we assessed concordance with NGS results, turnaround time, and TTI of EGFR therapy, and we evaluated reimbursement data.

RESULTS

Between January 2015 and September 2017, we performed 243 rapid EGFR tests and identified EGFR mutations in 43 patients (18%). With NGS results as a reference, sensitivity and specificity of the rapid EGFR polymerase chain reaction assay were 98% and 100%, respectively. The median turnaround time for NGS was 14 days, compared with 7 days for rapid testing (P < .001). In the rapid group, 95% of patients received an EGFR inhibitor in the first-line setting. The median TTI of EGFR therapy was significantly shorter in the rapid cohort when compared with 121 historical cases (22 v 37 days; P = .01). Escalation of the initiative into an interdisciplinary ultra-rapid next-day frozen-section workflow for highly symptomatic patients (n = 8) resulted in a reduction in the median (± standard deviation) turnaround time to 1 ± 0.4 days and allowed several patients to initiate therapy within 1 week of biopsy. An extended 9-month clinical evaluation phase confirmed operational sustainability (turnaround times: ultra-rapid, 0.81 ± 0.4 days; rapid, 3 ± 1.5 days), and a 63% reimbursement rate indicated financial sustainability.

CONCLUSION

Rapid genotyping facilitates earlier initiation of EGFR-directed therapies without compromising NGS workflows.

Clinicopathologic Features of Non-Small-Cell Lung Cancer Harboring an NTRK Gene Fusion

Purpose

Gene rearrangements involving NTRK1/2/3 can generate fusion oncoproteins containing the kinase domains of TRKA/B/C, respectively. These fusions are rare in non-small cell lung cancer (NSCLC), with frequency previously estimated to be <1%. Inhibition of TRK signaling has led to dramatic responses across tumor types with NTRK fusions. Despite the potential benefit of identifying these fusions, the clinicopathologic features of NTRK fusion-positive NSCLCs are not well characterized.

Methods

We compiled a database of NSCLC cases harboring NTRK fusions. We characterized the clinical, molecular, and histologic features of these cases with central review of histology.

Results

We identified 11 NSCLC cases harboring NTRK gene fusions verified by next-generation sequencing (NGS) and with available clinical and pathologic data, forming the study cohort. Fusions involved NTRK1 (7 cases) and NTRK3 (4 cases), with 5 and 2 distinct fusion partners, respectively. Cohort patients were 55% male, with a median age at diagnosis of 47.6 years (range 25.3-86.0) and a median pack year history of 0 (range 0-58). 73% of patients had metastatic disease at diagnosis. No concurrent alterations in KRAS, EGFR, ALK, ROS1, or other known oncogenic drivers were identified. Nine cases were adenocarcinoma, including 2 invasive mucinous adenocarcinomas and 1 adenocarcinoma with neuroendocrine features; one was squamous cell carcinoma; and one was neuroendocrine carcinoma. By collating data on 4872 consecutively screened NSCLC cases from unique patients, we estimate a frequency of NTRK fusions in NSCLC of 0.23% (95% CI 0.11-0.40).

Conclusion

NTRK fusions occur in NSCLCs across genders, ages, smoking histories, and histologies. Given the potent clinical activity of TRK inhibitors, we advocate that all NSCLCs be screened for NTRK fusions using a multiplexed NGS-based fusion assay.

Primary Patient-Derived Cancer Cells and Their Potential for Personalized Cancer Patient Care

Personalized cancer therapy is based on a patient's tumor lineage, histopathology, expression analyses, and/or tumor DNA or RNA analysis. Here, we aim to develop an in vitro functional assay of a patient's living cancer cells that could complement these approaches. We present methods for developing cell cultures from tumor biopsies and identify the types of samples and culture conditions associated with higher efficiency of model establishment. Toward the application of patient-derived cell cultures for personalized care, we established an immunofluorescence-based functional assay that quantifies cancer cell responses to targeted therapy in mixed cell cultures. Assaying patient-derived lung cancer cultures with this method showed promise in modeling patient response for diagnostic use. This platform should allow for the development of co-clinical trial studies to prospectively test the value of drug profiling on tumor-biopsy-derived cultures to direct patient care.

Abstract 2972: Co-clinical trial of olaparib and temozolomide in SCLC PDX models uncovers new biomarkers of sensitivity

Introduction: Small cell lung cancer (SCLC) is a common and rapidly fatal malignancy for which no biomarker-targeted therapies have been developed. Despite a critical need, progress suffers from (1) scarcity of cutting-edge laboratory models and (2) absence of promising targets. Patient-derived xenografts (PDX) may faithfully model the clinical disease, but because SCLC is rarely biopsied or resected, specimens for PDX generation are scarce. PARP inhibition has recently emerged as a compelling strategy for SCLC, and an ongoing phase 1/2 trial of combination olaparib tablets and temozolomide (O/T) has shown promising activity in patients. However, biomarkers for patient selection remain elusive.

Methods: We generated SCLC PDX models from circulating tumor cells (CTCs), biopsies and malignant effusions. CTCs were enriched with an automated microfluidic device, the CTC-iChip. To assess the genomic fidelity of the models, we performed comparative whole exome sequencing (WES) and RNA-seq on 6 sets of corresponding patient biopsies, founder (P0) PDX tumors, and early-passage PDXs. We then assessed the activity of combination O/T in a panel of PDX models, and compared PDX responses with molecular profiles to identify candidate biomarkers.

Results: 44 PDXs were generated from 32 patients, including 6 sets of serial models and 4 synchronous CTC- and biopsy-derived models. PDXs were derived with high efficiency from both CTCs (35% per blood draw) and biopsies/effusions (82% per implant). WES demonstrated that somatic alterations in tumor biopsies were stably maintained in both CTC and biopsy-derived models, without significant accumulation of new mutations, and transcriptional profiles remained consistent through early passages. Six models were derived from O/T trial patients, including two sets of serial models before and after durable responses. The serial models faithfully recapitulated patient responses to O/T: pre-trial models were highly sensitive and post-relapse were highly resistant. The co-clinical trial was expanded to 30 models, using the models derived from trial patients to delineate the margins of clinical sensitivity (6 models), intermediate sensitivity (6 models) and resistance (18 models). Among the molecular features evaluated, basal protein PARylation best distinguished the O/T-sensitive category from both intermediate (p &lt; 0.001) and resistant models (p &lt; 0.0001). In addition, PARylation decreased after relapse in serial models from O/T trial patients.

Conclusions: Both biopsy- and CTC-derived SCLC PDX models faithfully recapitulate the genomic and functional features of the donor patient tumor. O/T sensitivity in this panel correlated with basal PARylation. The value of the co-clinical trial is the potential to refine the clinical application of O/T in real time, to optimize follow-on clinical trials and to develop biomarker-directed therapy for SCLC.

Citation Format: Benjamin J. Drapkin, Julie George, Marcello Stanzione, Beow Y. Yeap, Mari Mino-Kenudson, Camilla L. Christensen, Ruben Dries, Sarah Phat, Jun Zhong, David T. Myers, Joseph A. Licausi, Tilak Sundaresan, Marina Kem, Nima Abedpour, Leica V. Sequist, Alice T. Shaw, Aaron N. Hata, Mehmet Toner, Shyamala Maheswaran, Daniel A. Haber, Martin Peifer, Roman K. Thomas, Anna F. Farago, Nicholas J. Dyson. Co-clinical trial of olaparib and temozolomide in SCLC PDX models uncovers new biomarkers of sensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2972.

Brigatinib in Patients With Alectinib-Refractory ALK-Positive NSCLC

INTRODUCTION

The second-generation anaplastic lymphoma kinase (ALK) inhibitor alectinib recently showed superior efficacy compared to the first-generation ALK inhibitor crizotinib in advanced ALK-rearranged NSCLC, establishing alectinib as the new standard first-line therapy. Brigatinib, another second-generation ALK inhibitor, has shown substantial activity in patients with crizotinib-refractory ALK-positive NSCLC; however, its activity in the alectinib-refractory setting is unknown.

METHODS

A multicenter, retrospective study was performed at three institutions. Patients were eligible if they had advanced, alectinib-refractory ALK-positive NSCLC and were treated with brigatinib. Medical records were reviewed to determine clinical outcomes.

RESULTS

Twenty-two patients were eligible for this study. Confirmed objective responses to brigatinib were observed in 3 of 18 patients (17%) with measurable disease. Nine patients (50%) had stable disease on brigatinib. The median progression-free survival was 4.4 months (95% confidence interval [CI]: 1.8-5.6 months) with a median duration of treatment of 5.7 months (95% CI: 1.8-6.2 months). Among 9 patients in this study who underwent post-alectinib/pre-brigatinib biopsies, 5 had an ALK I1171X or V1180L resistance mutation; of these, 1 had a confirmed partial response and 3 had stable disease on brigatinib. One patient had an ALK G1202R mutation in a post-alectinib/pre-brigatinib biopsy, and had progressive disease as the best overall response to brigatinib.

CONCLUSIONS

Brigatinib has limited clinical activity in alectinib-refractory ALK-positive NSCLC. Additional studies are needed to establish biomarkers of response to brigatinib and to identify effective therapeutic options for alectinib-resistant ALK-positive NSCLC patients.

Genomic and Functional Fidelity of Small Cell Lung Cancer Patient-Derived Xenografts

Small cell lung cancer (SCLC) patient-derived xenografts (PDX) can be generated from biopsies or circulating tumor cells (CTC), though scarcity of tissue and low efficiency of tumor growth have previously limited these approaches. Applying an established clinical-translational pipeline for tissue collection and an automated microfluidic platform for CTC enrichment, we generated 17 biopsy-derived PDXs and 17 CTC-derived PDXs in a 2-year timeframe, at 89% and 38% efficiency, respectively. Whole-exome sequencing showed that somatic alterations are stably maintained between patient tumors and PDXs. Early-passage PDXs maintain the genomic and transcriptional profiles of the founder PDX. In vivo treatment with etoposide and platinum (EP) in 30 PDX models demonstrated greater sensitivity in PDXs from EP-naïve patients, and resistance to EP corresponded to increased expression of a MYC gene signature. Finally, serial CTC-derived PDXs generated from an individual patient at multiple time points accurately recapitulated the evolving drug sensitivities of that patient's disease. Collectively, this work highlights the translational potential of this strategy.Significance: Effective translational research utilizing SCLC PDX models requires both efficient generation of models from patients and fidelity of those models in representing patient tumor characteristics. We present approaches for efficient generation of PDXs from both biopsies and CTCs, and demonstrate that these models capture the mutational landscape and functional features of the donor tumors. Cancer Discov; 8(5); 600-15. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 517.

Efficacy of Larotrectinib in TRK Fusion-Positive Cancers in Adults and Children

BACKGROUND

Fusions involving one of three tropomyosin receptor kinases (TRK) occur in diverse cancers in children and adults. We evaluated the efficacy and safety of larotrectinib, a highly selective TRK inhibitor, in adults and children who had tumors with these fusions.

METHODS

We enrolled patients with consecutively and prospectively identified TRK fusion-positive cancers, detected by molecular profiling as routinely performed at each site, into one of three protocols: a phase 1 study involving adults, a phase 1-2 study involving children, or a phase 2 study involving adolescents and adults. The primary end point for the combined analysis was the overall response rate according to independent review. Secondary end points included duration of response, progression-free survival, and safety.

RESULTS

A total of 55 patients, ranging in age from 4 months to 76 years, were enrolled and treated. Patients had 17 unique TRK fusion-positive tumor types. The overall response rate was 75% (95% confidence interval [CI], 61 to 85) according to independent review and 80% (95% CI, 67 to 90) according to investigator assessment. At 1 year, 71% of the responses were ongoing and 55% of the patients remained progression-free. The median duration of response and progression-free survival had not been reached. At a median follow-up of 9.4 months, 86% of the patients with a response (38 of 44 patients) were continuing treatment or had undergone surgery that was intended to be curative. Adverse events were predominantly of grade 1, and no adverse event of grade 3 or 4 that was considered by the investigators to be related to larotrectinib occurred in more than 5% of patients. No patient discontinued larotrectinib owing to drug-related adverse events.

CONCLUSIONS

Larotrectinib had marked and durable antitumor activity in patients with TRK fusion-positive cancer, regardless of the age of the patient or of the tumor type. (Funded by Loxo Oncology and others; ClinicalTrials.gov numbers, NCT02122913 , NCT02637687 , and NCT02576431 .).

Current standards for clinical management of small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive high-grade neuroendocrine carcinoma. Despite over 30 years of clinical research, little progress has been made in the management of SCLC, and outcomes remain poor. Here, we review the current clinical standards for management of SCLC and the data supporting these strategies.

Tracking the Evolution of Resistance to ALK Tyrosine Kinase Inhibitors through Longitudinal Analysis of Circulating Tumor DNA

Purpose

ALK rearrangements predict for sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, responses to ALK TKIs are generally short-lived. Serial molecular analysis is an informative strategy for identifying genetic mediators of resistance. Although multiple studies support the clinical benefits of repeat tissue sampling, the clinical utility of longitudinal circulating tumor DNA analysis has not been established in ALK-positive lung cancer.

Methods

Using a 566-gene hybrid-capture next-generation sequencing (NGS) assay, we performed longitudinal analysis of plasma specimens from 22 ALK-positive patients with acquired resistance to ALK TKIs to track the evolution of resistance during treatment. To determine tissue-plasma concordance, we compared plasma findings to results of repeat biopsies.

Results

At progression, we detected an ALK fusion in plasma from 19 (86%) of 22 patients, and identified ALK resistance mutations in plasma specimens from 11 (50%) patients. There was 100% agreement between tissue- and plasma-detected ALK fusions. Among 16 cases where contemporaneous plasma and tissue specimens were available, we observed 100% concordance between ALK mutation calls. ALK mutations emerged and disappeared during treatment with sequential ALK TKIs, suggesting that plasma mutation profiles were dependent on the specific TKI administered. ALK G1202R, the most frequent plasma mutation detected after progression on a second-generation TKI, was consistently suppressed during treatment with lorlatinib.

Conclusions

Plasma genotyping by NGS is an effective method for detecting ALK fusions and ALK mutations in patients progressing on ALK TKIs. The correlation between plasma ALK mutations and response to distinct ALK TKIs highlights the potential for plasma analysis to guide selection of ALK-directed therapies.