Actionable Driver Mutations Research Articles

Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression ― Interim Analysis of the First Randomized Study of Stereotactic Body Radiotherapy in Patients With Oligoprogressive Metastatic Cancers of the Lung and Breast

<h3>Purpose/Objective(s)</h3> We hypothesize that there is an oligoprogressive state in metastatic cancer, in which disease control can be improved with local therapy to progressive lesions only. This study therefore evaluated the impact of stereotactic body radiotherapy (SBRT) to sites of oligoprogression in patients with metastatic non-small-cell lung cancer (NSCLC) and breast cancer with 1-5 progressive lesions. <h3>Materials/Methods</h3> We enrolled patients with metastatic NSCLC or breast cancer who received ≥ 1 line of systemic therapy and had oligoprogressive lesions amenable to SBRT. There was no upper limit of non-progressive lesions. Oligoprogression was defined as Response Evaluation or Positron Emission Tomography Response Criteria in Solid Tumors documented progression ≤ 5 individual lesions. Stratification factors included number of progressive sites (1 vs. 2-5), prior systemic therapy (immunotherapy vs. other), primary tumor (NSCLC vs. breast), and tumor marker status (driver mutation and hormone receptor status). Patients were randomized 1:1 between SBRT to all progressive sites plus palliative standard of care (SOC) vs. palliative SOC only. Systemic therapy was per physician's discretion. The primary endpoint was progression-free survival (PFS). We used a randomized phase II design with a one-sided alpha of 0.05 and a power of 0.80, yielding a target accrual of 160 patients. PFS was compared using one-sided stratified log-rank test. One interim analysis was planned. <h3>Results</h3> From January 2019 to May 2021, 102 patients were randomized - 58 NSCLC (30 in the SBRT arm) and 44 breast (22 in each arm). Median age was 67. Most patients (75%) had > 1 site of oligoprogression and 47% had > 5 total metastatic lesions. Fifty-five (54%) patients received immunotherapy. The majority of NSCLC (86%) did not harbor an actionable driver mutation and 32% of breast cancer were triple negative. Baseline factors were balanced between arms. At a median follow-up of 51 weeks, 71 patients progressed and 30 died. Median PFS was 22 weeks in the SBRT arm vs. 10 weeks in the palliative SOC arm (p=0.005). This was driven entirely by the PFS benefit from SBRT in the NSCLC patients (44 weeks with SBRT vs. 9 weeks with SOC; p=0.004). No difference in median PFS was seen in the breast cohort (18 weeks with SBRT vs. 17 weeks with SOC; p=0.5). In multivariable Cox model inclusive of stratification factors, age, sex, lines of systemic therapy, and change of systemic therapy, the PFS benefit of SBRT remained substantial in the NSCLC cohort (Hazard Ratio: 0.38; 95% CI: 0.18-77; p=0.007). Grade ≥2 adverse events occurred in 8 patients in the SBRT arm, including 1 grade 3 pneumonitis. <h3>Conclusion</h3> Inthis pre-planned interim analysis of the first and largest randomized trial of radiotherapy for oligoprogressive metastatic NSCLC and breast cancer, we demonstrated the benefit of SBRT to sites of oligoprogression on overall PFS, meeting the primary endpoint. The mechanism of the differential benefits between NSCLC and breast cohorts merits further evaluation.

Molecular Pathogenesis of Gastrointestinal Stromal Tumor: A Paradigm for Personalized Medicine.

Over the past three to four decades, the molecular pathogenesis of gastrointestinal stromal tumors (GISTs) has been elucidated in great detail. In this review, we discuss the biological genesis of GISTs, identification of the various primary activating driver mutations (focusing on KIT and PDGFRA), oncogene addiction and targeted therapies with imatinib and other tyrosine kinase inhibitors, and the subsequent characterization of the various mechanisms of drug resistance. We illustrate how GIST has become a quintessential paradigm for personalized medicine.

Systemic Therapy for Lung Cancer Brain Metastases.

Systemic therapy for brain metastases (BM) is quickly moving from conventional cytotoxic chemotherapy toward targeted therapies, that allow a disruption of driver molecular pathways. The discovery of actionable driver mutations has led to the development of an impressive number of tyrosine kinase inhibitors (TKIs), that target the epidermal growth factor receptor (EGFR) mutations, anaplastic-lymphoma-kinase (ALK) rearrangements, and other rare molecular alterations in patients bearing metastatic non-small cell lung cancer (NSCLC) in the brain, with remarkable results in terms of intracranial disease control and overall survival. Moreover, these drugs may delay the use of local therapies, such as stereotactic radiosurgery (SRS) or whole-brain radiotherapy (WBRT). New drugs with higher molecular specificity and ability to cross the CNS barriers (BBB, BTB and blood-CSF) are being developed. Two major issues are related to targeted therapies. First, the emergence of a resistance is a common event, and a deeper understanding of molecular pathways that are involved is critical for the successful development of effective new targeted agents. Second, an early detection of tumor progression is of utmost importance to avoid the prolongation of an ineffective therapy while changing to another drug. In order to monitor over time the treatment to targeted therapies, liquid biopsy, that allows the detection in biofluids of either circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) or exosomes, is increasingly employed in clinical trials: with respect to BM the monitoring of both blood and CSF is necessary. Also, radiomics is being developed to predict the mutational status of the BM on MRI.For patients without druggable mutations or who do not respond to targeted agents, immunotherapy with checkpoint inhibitors is increasingly employed, alone or in combination with radiotherapy. Pseudoprogression after immunotherapy alone maybe a challenge for several months after the start of treatment, and the same is true for radionecrosis after the combination of immunotherapy and SRS. In this regard, the value of advanced MRI techniques and PET imaging for a better distinction of pseudoprogression/radionecrosis and true tumor progression is promising, but needs validation in large prospective datasets. Last, a new frontier in the near future will be chemoprevention (primary and secondary), but we need to identify among solid tumors those subgroups of patients with a higher risk of relapsing into the brain and novel drugs, active on either neoplastic or normal cells of the microenvironment, that are cooperating in the invasion of brain tissue.

P14.04 A Phase 2 Multicenter Study of Iovance Autologous Tumor Infiltrating Lymphocytes (TIL, LN-145) Cell Therapy in Patients With Metastatic NSCLC

Patients with metastatic non-small cell lung cancer (mNSCLC) without actionable driver mutation(s) who have progressed after cytotoxic chemotherapy plus immune checkpoint inhibitors (ICI) have limited treatment options and represent an unmet need. The safety and efficacy of TIL cell therapy for mNSCLC patients who failed to respond or progressed on nivolumab has been evaluated in a Phase 1 clinical trial (Creelan B, AACR 2020), demonstrating an objective response rate (ORR) of 25% including 17% durable CRs.

Real-world trends in EU4 and the UK in frontline (1L) maintenance (MT) for nonsquamous (NSQ) advanced non-small cell lung cancer (aNSCLC) without actionable mutations after introduction of immune checkpoint inhibitors.

296 Background: Immune checkpoint (PD-1, PD-L1) inhibitors are important in the treatment (Tx) of aNSCLC, as reflected in European Society for Medical Oncology (ESMO) guidelines. Pembrolizumab (pembro) combined with pemetrexed and platinum-based chemotherapy is a standard induction option in 1L Tx of NSQ aNSCLC. Decisions about 1L maintenance consider response and toxicity after induction, performance status, and patient preference. This study documents recent real-world 1L MT patient characteristics and Tx in EU4 (France, Germany, Italy, Spain) and UK. Methods: This retrospective analysis used patient chart review completed by treating physicians in EU4 and UK between 1 Jan 2018 and 31 Dec 2020 in the IQVIA Oncology Dynamics (OD) database. Adults (≥21 years) with confirmed NSQ aNSCLC (stage IIIB/C or IV) without actionable oncogenic driver mutations and with Eastern Cooperative Oncology Group (ECOG) status of 0 or 1 were included. 1L MT and Tx characteristics and trends over time were evaluated overall and by country. Results: In total, 1,814 NSQ aNSCLC patients receiving 1L MT Tx met the inclusion criteria; 29% of patients entered the analysis in 2018, 40% in 2019, and 31% in 2020. Most patients were male (61%), in the 46–65 age group (51%), current/ex-smokers (87%), and treated in the UK (29%) or Germany (24%); 94% were metastatic (stage IV), 10% presented with CNS/brain metastases, and 77% had ECOG score of 1. Overall, 91% were tested for PD-L1; of these, 47% had tumor proportion score (TPS) of ≥1% to 49%, 22% had TPS of ≥50%, and 21% tested negative. Baseline demographic and clinical characteristics were generally similar among countries. The top two Tx in 1L MT were pemetrexed (40%; range: 12% in Germany to 66% in Italy) and pembro (28%; range: 14% in Spain to 49% in Germany) monotherapies. Overall use of pemetrexed-based Tx in 1L MT decreased from 68% in 2018 Q1 to 56% in 2020 Q4, while pembro-based Tx increased from 18% in 2018 Q1 to 73% in 2020 Q4 in 1L MT. Conclusions: Despite ESMO guidelines, this real-world data suggests notable differences between European countries in 1L MT Tx for NSQ aNSCLC, with trends over time likely reflecting introduction and adoption of pembro regardless of PD-L1 status. Awareness of country and time-variability in clinical practice are critical for implementing clinical trials and updating clinical practice guidelines to maximize Tx benefits with improved tolerability.[Table: see text]

The immune microenvironment in EGFR- and ERBB2-mutated lung adenocarcinoma

BackgroundTargeted therapies have improved survival and quality of life for patients with non-small-cell lung cancer with actionable driver mutations. However, epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 gene (HER2, also known as ERBB2) exon 20 insertions (Ex20mut) are characterized by a poor response to currently approved tyrosine kinase inhibitors and immunotherapies. The underlying immune biology is not well understood.Materials and methodsWe carried out messenger RNA expression profiling of lung adenocarcinomas (ADCs) with ERBB2 (n = 19) and EGFR exon 20-insertion mutations (n = 13) and compared these to tumors with classical EGFR mutations (n = 40, affecting EGFR exons 18, 19 or 21) and EGFR/ERBB2 mutation-negative lung ADC (EGFR/ERBB2wt, n = 26) focusing on immunologically relevant transcripts. Tumor-infiltrating immune cells were estimated from gene expression profiles.ResultsCytotoxic cells were significantly lower in EGFR-mutated tumors regardless of the affected exon, while Th1 cells were significantly lower in EGFR-Ex20mut compared to EGFR/ERBB2wt tumors. We assessed the differentially expressed genes of ERBB2-Ex20mut and EGFR-Ex20mut tumors compared to EGFR-Ex18/19/21mut and EGFR/ERBB2wt tumors. Of these, the genes GUSB, HDAC11, IFNGR2, PUM1, RASGRF1 and RBL2 were up-regulated, while a lower expression of CBLC, GBP1, GBP2, GBP4 and MYC was observed in all three comparison groups. The omnibus test revealed 185 significantly (FDR = 5%) differentially expressed genes and we found these four most significant gene expression changes in the study cohort: VHL and JAK1 were overexpressed in ERBB2-Ex20mut and EGFR-Ex20mut tumors compared to both EGFR-Ex18/19/21mut and EGFR/ERBB2wt tumors. RIPK1 and STK11IP showed the highest expression in ERBB2-Ex20mut tumors.ConclusionsTargeted gene expression profiling is a promising tool to read out the characteristics of the tumor microenvironment from routine diagnostic lung cancer biopsies. Significant immune reactivity and specific immunosuppressive characteristics in ERBB2-Ex20mut and EGFR-Ex20mut lung ADC with at least some degree of immune infiltration support further clinical evaluation of immune-modulators as partners of immune checkpoint inhibitors in such tumors.

Abstract CT246: A phase 2 multicenter study of autologous tumor infiltrating lymphocytes (TIL, LN-145) cell therapy in patients with metastatic non-small cell lung cancer (mNSCLC)

Abstract Background Patients with mNSCLC without actionable driver mutation(s) who have progressed after cytotoxic chemotherapy plus immune checkpoint inhibitors (ICI) ± bevacizumab have limited treatment options and represent an unmet need. The safety and efficacy of TIL cell therapy for mNSCLC patients who failed to respond or progressed on nivolumab has been evaluated in a Phase 1 clinical trial (Creelan B., AACR 2020), demonstrating an objective response rate (ORR) of 25% including 17% durable CRs. This provides a clear rationale for initiation of IOV-LUN-202 study, evaluating Iovance Gen 2 TIL cell therapy with LN-145 in patients with mNSCLC without actionable driver mutation(s), who have progressed on or following a single line of approved systemic therapy consisting of combined ICI + chemotherapy ± bevacizumab. Trial Design IOV-LUN-202 (NCT04614103) is a prospective, open-label, multi-cohort, non-randomized, multicenter Phase 2 study. Patient cohorts (n=40 ea) based on tumor proportion score (TPS) at metastatic diagnosis prior to ICI use are Cohort 1 (TPS &amp;lt;1%) and Cohort 2 (TPS ≥ 1%). Cohort 3 (TPS &amp;lt;1%; n=15), utilizes core biopsies for tumor acquisition for patients unable to undergo a surgical harvest. LN-145 is generated at centralized GMP facilities and the final cryopreserved infusion product is shipped to the sites. All patients receive TIL therapy consisting of nonmyeloablative lymphodepletion with cyclophosphamide (60 mg/kg X 2) + fludarabine (25 mg/m2 X 5), followed by a single infusion of autologous LN-145 (Day 0) and up to 6 doses of IL-2 (600,000 IU/kg). Key eligibility includes: ≥ 18 y of age; 1 prior line of therapy; ≥ 1 lesion(s) available for TIL generation and a remaining RECIST-measurable lesion; and ECOG PS of 0-1. For each cohort, the primary endpoint is ORR per RECIST 1.1. Secondary endpoints are safety, CR rate, DOR, DCR, PFS, OS and efficiency of generating LN-145 from tumor core biopsies (Cohort 3). Table 1.IOV-LUN-202 Patient CohortsPATIENT POPULATIONCOHORTMetastatic NSCLC without an actionable driver mutation and progressive disease on or following a single line of approved systemic therapy including ICI + Chemo ± BevacizumabSAMPLE SIZE1PD-L1 TPS &amp;lt; 1%N = 402PD-L1 TPS ≥ 1%N = 403PD-L1 TPS &amp;lt; 1%/Core BiopsiesN = 154RetreatmentN = undefined Citation Format: Erminia Massarelli, Zelanna Goldberg, Alex Cacovean, Bhagyashree Yadav, Guang Chen, Madan Jagasia, Friedrich Graf Finckenstein, Maria Fardis, Ammar Sukari. A phase 2 multicenter study of autologous tumor infiltrating lymphocytes (TIL, LN-145) cell therapy in patients with metastatic non-small cell lung cancer (mNSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT246.

Abstract 102: Clinicopathological and molecular characteristics, treatment patterns, and outcomes in patients with KRAS p.G12C-mutated metastatic non-small cell lung cancer (NSCLC) in the AACR Project GENIE database

Abstract Introduction: Mutations in the RAS family of proto-oncogenes are frequently found in NSCLC, with KRAS being the most prevalent mutated isoform. Of KRAS mutations, the most common is KRAS G12C, representing ~40% of KRAS mutations and occurring in ~13% of all lung adenocarcinoma cases. The objective of this study is to describe clinicopathological and molecular characteristics, treatment patterns, and outcomes in patients with KRAS G12C-mutated metastatic NSCLC using the AACR Project GENIE database. Methods: An observational retrospective study of adult patients (&amp;gt;18 years of age) with KRAS G12C-mutated metastatic NSCLC from three US academic comprehensive cancer centers in the AACR Project GENIE database was undertaken using de-identified data. Patients were eligible if their tumor tested positive for KRAS G12C mutation by next-generation sequencing at the participating institutions. Event-time distributions were estimated using the Kaplan-Meier method, and multivariable models were fitted to estimate adjusted hazard ratios (aHRs) by Cox proportional models. Patients with large panel sequencing performed up to Dec 31, 2018 were included. All available data until Aug 1, 2019 were collected. Results: Of the 416 eligible patients included in this analysis, 91.6% were white, 64.4% were female, median age at metastatic diagnosis was 68.2 years (range: 37.6-86.2), and 97.1% were former or current smokers. 65.1% of patients had stage 4 NSCLC at diagnosis, and most tumors were adenocarcinomas (85.8%). The KRAS G12C mutation was nearly mutually exclusive (≤ 1.0%) with other actionable driver mutations in EGFR, ALK, ROS1, and BRAF but was co-occurred with STK11 (23.6%) and KEAP1 (9.9%) mutations. Among patients who received PD-(L)1 monotherapy (n=110), median progression-free (mPFS) and overall survival (mOS) were 4.6 and 11.9 months, respectively, while among those who received chemotherapy only (n=133) mPFS and mOS were 4.1 and 12.1 months, respectively. When clinical outcomes were analyzed according to co-occurring genomic alterations, we found that KRAS/STK11 co-mutations were associated with significantly worse outcomes with immunotherapy (PFS: aHR 0.44, P=0.002; OS: aHR 0.42, P=0.003) but not with chemotherapy (PFS: aHR 0.82, P=0.44; OS: aHR 0.81, P=0.43). There was no significant impact of co-occurring KRAS mutations with KEAP1, SMARCA4, ATM, RBM10 and TP53 on clinical outcomes to either PD-(L)1 inhibition or chemotherapy. Conclusions: KRAS G12C mutant NSCLC represents a heterogeneous group of lung cancers and its genomic diversity is reflected in differential responses to therapy. These findings highlight the urgent clinical need for molecular biomarker-driven therapies in this subset of patients. Citation Format: Biagio Ricciuti, Chenguang Wang, Hira Rizvi, Jacklynn Egger, Michele LeNoue-Newton, Marilyn Holt, Shivani Aggarwal, Huakang Tu, Hil Hsu, Xuena Wang, Gataree Ngarmchamnanrith, Victoria Chia, Jocelyn Lee, Robert Scharpf, Valsamo Anagnostou, Christine Lovly, Greg Riely, Mark Awad. Clinicopathological and molecular characteristics, treatment patterns, and outcomes in patients with KRAS p.G12C-mutated metastatic non-small cell lung cancer (NSCLC) in the AACR Project GENIE database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 102.

Abstract 2299: An unbiased in vivo screen for activating EGFR mutations

Abstract Cancer tissues harbor thousands of mutations, and a given oncogene may be mutated at hundreds of sites across different samples. Most of these somatic mutations are expected to be inconsequential passenger mutations that reflect the general instability of the tumors. The discovery of most of the currently known driver mutations has been facilitated by their accumulation in mutation hot-spots within their respective genes. However, a vast majority of mutations in cancer tissues are rare and their functional significance remains unknown. Several lines of in vitro and clinical evidence also indicate that there is a significant number of, as yet unidentified, activating driver mutations which could serve as predictive markers in oncology. We are developing our in vitro Screen for Activating Mutations (“iSCREAM”)[1] further and advancing it to better recapitulate natural intratumor heterogeneity by taking the system in vivo. To establish the in vivo model for screening activating mutations we utilize the SALE-Y cells which are immortalized human small airway epithelial cells harboring an activating YAP1 variant[2]. In immunocompromised mice, SALE-Y cells fail to form tumors up to 120 days, but they become tumorigenic after transduction of mutations activating the EGFR-MAPK signaling pathway[2]. We will use the SALE-Y cell background for transduction of an expression library encoding thousands of different randomly mutated variants of the kinase to be tested. EGFR will be used to set up the model because: i) EGFR mutants are known to of transforming the SALE-Y cells[2] and ii) we have previously used EGFR as a model to set up the in vitro screen[1]. The SALE-Y expressing the random collection of EGFR variants will be inoculated subcutaneously into immunocompromised mice, and the activating mutations will be given an opportunity to outcompete passenger mutations during subsequent expansion and suvival of the xenograft. Genomic DNA will be harvested from the tumor tissue and subjected to targeted next-generation sequencing allowing unbiased identification of enriched activating mutations promoting tumor growth.

Comprehensive molecular profiling of pulmonary pleomorphic carcinoma

Information regarding the molecular features of pulmonary pleomorphic carcinoma (PPC) is insufficient. Here, we performed next-generation sequencing to determine the genomic and transcriptomic profiles of PPC. We sequenced the DNAs and RNAs of 78 specimens from 52 patients with PPC. We analyzed 15 PPC cases to identify intratumoral differences in gene alterations, tumor mutation burden (TMB), RNA expression, and PD-L1 expression between epithelial and sarcomatoid components. The genomic alterations of six cases of primary tumors and corresponding metastatic tumors were analyzed. KRAS mutations (27%) were the most common driver mutations, followed by EGFR (8%), and MET (8%) mutations. Epithelial and sarcomatoid components shared activating driver mutations, and there were no significant differences in CD274 expression or TMB between the two components. However, PD-L1 was highly expressed in the sarcomatoid component of several cases compared with the epithelial component. Primary and metastatic tumors shared oncogenic mutations among genes such as KRAS and TP53, and additional alterations including NOTCH4 mutations were specifically identified in the metastatic regions. Our data suggest that therapies targeting activating driver mutations may be effective for patients with PPC and that immune checkpoint inhibitors of PPC may be recommended after careful assessment of PD-L1 expression in each epithelial and sarcomatoid component.

SMARCA4/BRG1 protein-deficient thoracic tumors dictate re-examination of small biopsy reporting in non-small cell lung cancer.

BackgroundSMARCA4/BRG1 protein–deficient lung adenocarcinomas and thoracic sarcoma are recently described entities that lack distinctive histological features, transcription termination factor 1 (TTF1) reactivity, and actionable driver mutations. The current diagnostic path for small lung biopsies as recommended by the World Health Organization (WHO, 2015) is likely to categorize these as non–small cell carcinoma–not otherwise specified (NSCC-NOS). The present study attempts to define the subtle but distinctive clinicopathologic features of SMARCA4/BRG1 protein-deficient thoracic tumors; highlight their unique biology; and addresses the unmet need to segregate these using a new, tissue-proficient diagnostic pathway.MethodsAll lung biopsies and those from metastatic sites in patients with suspected advanced lung cancer and classified as NSCC-NOS as per WHO (2015) guidelines were subjected to BRG1 testing by immunohistochemistry. SMARCA4/BRG1 protein–deficient thoracic tumors were evaluated by an extended immunohistochemistry panel. Predictive biomarker and programmed death–ligand 1 testing was conducted in all cases.ResultsOf 110 cases, nine were found to be SMARCA4/BRG1 protein-deficient; six were identified as SMARCA4/BRG1 protein–deficient lung adenocarcinomas, and three were SMARCA4/BRG1 protein-deficient thoracic sarcomas. The histology ranged from poorly differentiated to undifferentiated to rhabdoid. None of the cases showed significant expression of TTF1 or p40, and no actionable mutation was identified.ConclusionsIt is difficult to separate BRG1-deficient lung adenocarcinomas and thoracic sarcomas based on morphology alone. We propose a diagnostic pathway for small biopsies of thoracic tumors to segregate these distinct entities so that they can be studied more efficaciously for new biomarkers and therapeutic options.

Anti-PD1/PD-L1 Immunotherapy for Non-Small Cell Lung Cancer with Actionable Oncogenic Driver Mutations.

Anti-PD1/PD-L1 immunotherapy has emerged as a standard of care for stage III-IV non-small cell lung cancer (NSCLC) over the past decade. Patient selection is usually based on PD-L1 expression by tumor cells and/or tumor mutational burden. However, mutations in oncogenic drivers such as EGFR, ALK, BRAF, or MET modify the immune tumor microenvironment and may promote anti-PD1/PD-L1 resistance. In this review, we discuss the molecular mechanisms associated with these mutations, which shape the immune tumor microenvironment and may impede anti-PD1/PD-L1 efficacy. We provide an overview of the current clinical data on anti-PD1/PD-L1 efficacy in NSCLC with oncogenic driver mutation.

PCN245 Examining Longitudinal Practice Patterns in the use of ANTI-PD-1 and ANTI-PD-L1 Inhibitors as First-Line Therapy in Non-Small Cell Lung Cancer Patients in the US

Immune checkpoint inhibitors targeting the programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1) axis (collectively referred to as PD(L)1i) have demonstrated unprecedented clinical activity in patients with non-small cell lung cancer (NSCLC). This US-based real-world study examined changes in the landscape of first-line therapies for NSCLC since the introduction of PD(L)1i. NSCLC patients initiating first-line treatment were identified in the IBM MarketScan® database (5/1/2017-1/31/2020). Patients were assigned to one of four cohorts based on first-line therapy: PD(L)1i monotherapy, chemotherapy only, PD(L)1i + chemotherapy, or targeted therapy for patients with actionable driver mutations. A total of 4,425 NSCLC patients starting first-line treatment during the study timeframe were identified: PD(L)1i monotherapy = 606 (13.7%), chemotherapy only = 1,903 (43.0%), PD(L)1i + chemotherapy = 1,353 (30.6%), targeted therapy = 563 (12.7%), with average age 62 years (SD= 10.26) and 50% male. PD(L)1i monotherapy was highest in 2017 (26.4%) and declined every 6 months to a low of 15.8% in the second half of 2019. A similar decline in utilization was observed for chemotherapy only (34.5% in 2017; 12.8% in the second half of 2019). These declines were alongside an increase in the use of PD(L)1i in combination with chemotherapy from 12.6% in 2017 to 24.2% in the second half of 2019. In 2017, 18%, 63%, and 19% received PD(L)1i monotherapy, chemotherapy only, and PD(L)1i + chemotherapy, respectively, compared to the second half of 2019 when 14% ,36%, and 49% received PD(L)1i monotherapy, chemotherapy only, and PD(L)1i + chemotherapy, respectively. Since the approval of PD(L)1i for NSCLC, their use has significantly increased for first-line treatment, especially in combination with chemotherapy. However, a substantial fraction of patients still received chemotherapy without immunotherapy despite guideline recommendations. More research is needed to better understand these changes in practice patterns.

A retrospective observational study of the natural history of advanced non–small-cell lung cancer in patients with KRAS p.G12C mutated or wild-type disease

IntroductionThe KRAS p.G12C mutation, prevalent in non–small-cell lung cancer (NSCLC), has only recently become a viable target. Here we present results of the largest retrospective observational study analyzing KRAS p.G12C in patients with advanced NSCLC. Materials and MethodsAdults with advanced NSCLC (All Advanced NSCLC cohort) and subcohorts with different mutation profiles (KRAS p.G12C [G12C] and KRAS/EGFR/ALK wild type [Triple WT]) diagnosed January 2011 to March 2019 were selected from a US clinico-genomic database; treatment-related characteristics, molecular profiles, real-world overall (rwOS) and progression-free survival (rwPFS) were analyzed. ResultsDemographics were similar across cohorts, with more smokers and nonsquamous cell carcinoma histology in the G12C cohort. KRAS p.G12C was nearly mutually exclusive (≤1.2 %) with known actionable driver mutations, but non-driver co-mutations were common (STK11, 21.5 %; KEAP1, 7.0 %; TP53, 48.0 %). Among G12C patients, 20 % had no documentation of receiving systemic therapy. Across treated G12C patients, 67 % received immune checkpoint inhibitors; first-line usage increased from 0% (2014) to 81 % (2019). Among G12C patients, median (95 % CI) rwOS was 12.0 (9.6–15.3), 9.5 (8.1–13.1), and 6.7 (5.9–10.7) months after first, second, and third line of therapy, respectively; median (95 % CI) rwPFS was 5.0 (4.4–5.8), 4.0 (2.8–5.3), and 3.1 (2.4–4.3) months. Outcomes for the G12C subcohort were similar to those for all patients (All Advanced NSCLC cohort). Mutations in STK11/KEAP1 were associated with poorer survival across all cohorts. ConclusionThe poor outcomes associated with KRAS p.G12C mutated advanced NSCLC indicate an unmet need for more effective novel treatments.

Does order matter? Real-world data on outcomes of successive regimens involving anti-PDx-1 in advanced and metastatic non-small cell lung cancer.

e21159 Background: In 2020, 65% of newly diagnosed advanced (adv)or metastatic (met) NSCLC patients in US started first line (1L) systemic therapy on anti-PDx-1 regimen, 53% of second line (2L). Between broader approvals of anti-PDx-1, increasing use in different therapy lines, and in different regimen combinations, selecting initial and subsequent regimens can be challenging, especially with limited research on outcomes based on order. This analysis uses real-world data to summarize treatment decisions made in a network of oncology centers and relates them to time to second disease progression (PFS2) and overall survival (OS). PRA US medical &amp; prescription claims – 2020 (Jan-Aug). Methods: Deidentified data on adv/met NSCLC patients were selected from Inteliquet’s Cancer Center Research Consortium partners, which comprises academic &amp; community oncology practices as well as integrated delivery networks across the United States. Analysis was limited to patients who started 1L systemic treatment in 2017 &amp; 2018 (index event), progressed and started 2L. Either 1L / 2L / both must have been anti-PDx-1 based regimen. Patients with known actionable driver mutations were excluded. Data from the following 24 months was used to identify regimens and time to progression. PFS2 and OS across the combined 1L and 2L treatment protocols were assessed by proportional hazards regression. The analysis was adjusted for age at diagnosis, gender, PS and treating organization. Results: 132 patients met the study criteria: 53% were female, the median age range at diagnosis was 60-69 years, and 73% were diagnosed with stage IV, and 76% had PS 0-2 at diagnosis. After 24 months, 86% were alive, all had one progression and 44% had a 2nd progression. The most frequently observed treatment patterns are summarized in the table. Conclusions: Same regimens in different order showed different outcomes. There is a significant benefit for both OS &amp; PFS2 by starting with a platinum doublet followed by IO PT, versus the same start followed by IO MT. There is a significant disadvantage in OS by starting with IO MT followed by platinum doublet, versus the reversed order. 1L IO PT versus baseline showed non-significant improvement in PFS2, but not OS.[Table: see text]

Outcomes and safety analysis of a phase IB trial of stereotactic body radiotherapy (SBRT) to all sites of oligometastatic non-small cell lung cancer combined with durvalumab and tremelimumab.

e21212 Background: Combining local ablative and systemic therapies in patients with oligometastatic NSCLC leads to improved overall survival (OS) and progression-free survival (PFS). The potential immunostimulatory effects of ablating all visible disease with SBRT in combination with dual immune checkpoint inhibition has prompted interest, but the toxicity and benefit are unknown. Methods: We conducted a phase Ib study to investigate the safety of SBRT, with doses between 30 and 50 Gy in five fractions to all sites of disease, followed by durvalumab 1500 mg IV in combination with tremelimumab 75 mg IV every 4 weeks x 4 cycles, followed by durvalumab maintenance until progression. Eligible patients had 1-6 extracranial metastatic sites, allowing multiple metastases per location, with all lesions suitable for SBRT, ECOG performance status 0-1, no actionable driver mutation, and no prior immunotherapy. The primary endpoint was safety of this combination. Secondary endpoints include PFS and OS. Dose-limiting toxicities (DLTs) (any Grade ≥ 3 toxicity) were evaluated from the first administration of SBRT until 28 days post start of durvalumab and tremelimumab. Baseline tumor mutational burden, PD-L1 expression on post-SBRT biopsy and circulating tumor cells will be correlated with outcomes. In this first cohort analysis, we assess the safety and outcomes of the first 17 patients. Results: From 2/2018-2/2021, the first 17 pts were enrolled. Characteristics of those enrolled included: median age 68 years, female/male 4/13, squamous/non-squamous 2/15, median number of non-central nervous system (CNS) metastatic sites 2 (1-5), median number of non-CNS metastatic lesions 2 (1-9), CNS involvement 6/17 (35.3%), previous treatment 4/17 (23.5%). DLTs were seen in 2/17 (11.8%) patients; DLTs were autoimmune hepatitis and autoimmune pancreatitis. Most treatment-related adverse events (TRAEs) were grade (G) 1/2. TRAEs included: all TRAEs n = 188, 88.2% (of patients); G 3 n = 17, 29.4%; G 4 n = 1, 5.8%. There were no treatment-related deaths. Five patients discontinued treatment due to grade 3/4 immune related adverse events (IRAE). At a median follow up of 20 months 11/17 (64.7%) patients are alive with 10/17 (58.8%) with no evidence of disease (NED). Six of 17 (35.2%) patients experienced disease progression and 4/17 (23.5%) patients died of disease progression. Median PFS and OS are not yet reached. Conclusions: There were no unexpected safety signals in the cohort of patients enrolled. The incidence of grade ≥ 3 IRAEs is similar to the treatment of advanced NSCLC and no additional toxicity was observed with the addition of SBRT. Clinical outcomes look promising with median OS and PFS not yet reached at 20 months median follow up. The study continues to enroll a second cohort and results will be updated. Clinical trial information: NCT03275597.

Mutational analysis of rare insertions and deletions in exon 18 and 19 of HER2 in Chinese patients with different cancer types.

3069 Background: HER2 belongs to the same family with EGFR and is known as an important cancer driver gene. Kinase domain insertions and deletions (KD indels) are frequent driver mutations in both EGFR and HER2. The most common HER2 KD indels are the exon 20 insertions while others are rarely reported. Our study aimed to investigate the role of less common HER2 KD indels in solid tumors. Methods: This study was performed in 63,267 Chinese patients including 53,591 patients with lung cancer, 5,888 patients with colorectal cancer, 3,774 patients with breast cancer and 14 patients with renal pelvis cancer. Tissue or plasma samples from the patients were subjected to capture-based targeted sequencing covering HER2 and other cancer related genes. The sequencing data of each patient were retrospectively collected and analyzed. The HER2 exon 18/19 indels identified in our study were compared with data from COSMIC and MSKCC. In vitro analysis in Ba/F3 cell lines was performed to assess drug response of different HER2 exon 18/19 indels. Results: We identified recurrent HER2 KD indels in exon 18 and 19, with a frequency of 0.04% (25/63,267). The data from COSMIC and MSKCC reported the prevalence of HER2 exon 18/19 indels ranging from 0.04% to 0.23% among breast, cervical, and pancreatic cancers. In our study, HER2 exon 18/19 indels were identified in 20 patients with lung cancer (0.037%), two with colorectal cancer (0.034%), two with breast cancer (0.053%) and one with renal pelvis cancer (7.143%). Only two patients (8%) harbored concurrent actionable driver mutations including EGFR mutation and MET amplification. Meanwhile, high level of normalized allelic frequency of HER2 exon 18/19 indels was presented in most patients (22/25, 88%). In lung cancer, the presence of EGFR driver mutation was less common in patients with HER2 exon 18/19 indels than wild type HER2 (5% vs. 47.4%, p &lt; 0.01). The rates of concurrent driver mutations in lung cancer were comparable between HER2 exon 18/19 indels and the two established HER2 drivers, exon 20 insertions and S310 mutations. The in vitro proliferation assay demonstrated that E698_P699insLL mutation in HER2 exon 18 and L755_E757delinsPQ mutation in HER2 exon 19 both conferred a survival advantage to Ba/F3 cells. Dose-response curves showed inhibitory effects on cell viability of several HER2 tyrosine kinase inhibitors including neratinib, lapatinib, poziotinib and afatinib. In particular, lapatinib, poziotinib and afatinib demonstrated comparable or stronger inhibitory ability toward the two HER2 mutants than wild type HER2 in terms of IC50. Conclusions: Our study revealed a novel class of HER2 KD indels in exon 18/19 that may act as driver mutations in several cancer types. The drug response observed in vitro indicated the potential to use anti- HER2 targeted therapies for HER2 exon 18/19 indels. Further studies on this rare type of HER2 mutation are warranted.

Reprogramming enriches for somatic cell clones with small-scale mutations in cancer-associated genes

Cellular therapies based on induced pluripotent stem cells (iPSCs) come out of age and an increasing number of clinical trials applying iPSC-based transplants are ongoing or in preparation. Recent studies, however, demonstrated a high number of small-scale mutations in iPSCs. Although the mutational load in iPSCs seems to be largely derived from their parental cells, it is still unknown whether reprogramming may enrich for individual mutations that could lead to loss of functionality and tumor formation from iPSC derivatives. 30 hiPSC lines were analyzed by whole exome sequencing. High accuracy amplicon sequencing showed that all analyzed small-scale variants pre-existed in their parental cells and that individual mutations present in small subpopulations of parental cells become enriched among hiPSC clones during reprogramming. Among those, putatively actionable driver mutations affect genes related to cell-cycle control, cell death, and pluripotency and may confer a selective advantage during reprogramming. Finally, a short hairpin RNA (shRNA)-based experimental approach was applied to provide additional evidence for the individual impact of such genes on the reprogramming efficiency. In conclusion, we show that enriched mutations in curated onco- and tumor suppressor genes may account for an increased tumor risk and impact the clinical value of patient-derived hiPSCs.

Circulating Tumor DNA Reflects Uveal Melanoma Responses to Protein Kinase C Inhibition.

Simple SummaryUveal melanoma (UM) is a rare cancer, with no effective standard systemic therapy in the metastatic setting. Over 95% of UM harbor activating driver mutations that can be detected in the circulation. In this study, circulating tumor DNA (ctDNA) was measured in 17 metastatic UM patients treated with protein kinase C inhibitor (PKCi)-based therapy. ctDNA predicted response to targeted therapy and increasing UM ctDNA preceded radiological progression with a lead-time of 4–10 weeks. Next generation sequencing (NGS) of ctDNA also identified prognostic and treatment resistance mutations. Longitudinal ctDNA monitoring is useful for monitoring disease response and progression in metastatic UM and is a valuable addition to adaptive clinical trial design.The prognosis for patients with UM is poor, and recent clinical trials have failed to prolong overall survival (OS) of these patients. Over 95% of UM harbor activating driver mutations, and this allows for the investigation of ctDNA. In this study, we investigated the value of ctDNA for adaptive clinical trial design in metastatic UM. Longitudinal plasma samples were analyzed for ctDNA in 17 metastatic UM patients treated with PKCi-based therapy in a phase 1 clinical trial setting. Plasma ctDNA was assessed using digital droplet PCR (ddPCR) and a custom melanoma gene panel for targeted next generation sequencing (NGS). Baseline ctDNA strongly correlated with baseline lactate dehydrogenase (LDH) (p < 0.001) and baseline disease burden (p = 0.002). Early during treatment (EDT) ctDNA accurately predicted patients with clinical benefit to PKCi using receiver operator characteristic (ROC) curves (AUC 0.84, [95% confidence interval 0.65–1.0, p = 0.026]). Longitudinal ctDNA assessment was informative for establishing clinical benefit and detecting disease progression with 7/8 (88%) of patients showing a rise in ctDNA and targeted NGS of ctDNA revealed putative resistance mechanisms prior to radiological progression. The inclusion of longitudinal ctDNA monitoring in metastatic UM can advance adaptive clinical trial design.

Moving beyond epidermal growth factor receptor resistance in metastatic non-small cell lung cancer - a drug development perspective.

Epidermal Growth Factor Receptor (EGFR) mutations are the most common targetable oncogenic driver mutation in metastatic non-small lung cancer (NSCLC). There have been significant advances in the management of metastatic EGFR-mutant NSCLC from the advent of first and second generation EGFR inhibitors to, more recently, the third-generation inhibitor osimertinib. Osimeritinib is now established as first-line therapy on the basis of improved outcomes compared to first and second generation agents. However, despite excellent initial response rates, responses may not be durable due to the development of acquired resistance. Understanding these mechanisms of resistance is critical to the development of rational drug and drug combinations capable of circumventing them. We discuss the major mechanisms of resistance to first, second and third generation EGFR TKIs. The potential of drug combinations utilising chemotherapy, immunotherapy and anti-angiogenic drugs are explored. We examine strategies to aid drug development, including circulating tumour DNA and novel trial designs.