Design, synthesis, and antitumor activity evaluation of potent fourth-generation EGFR inhibitors for treatment of Osimertinib resistant non-small cell lung cancer (NSCLC).

Epidermal growth factor receptor (EGFR) is one of the most studied drug targets for treating non-small-cell lung cancer (NSCLC). However, there are no approved inhibitors for the C797S resistance mutation caused by the third-generation EGFR inhibitor (Osimertinib). Therefore, the development of fourth-generation EGFR inhibitors is urgent. In this study, we clarified the structure-activity relationship of several synthesized compounds as fourth-generation inhibitors against human triple (Del19/T790M/C797S) mutation. Representative compound 52 showed potent inhibitory activity against EGFRL858R/T790M/C797S with an IC50 of 0.55 nM and significantly inhibited the proliferation of the Ba/F3 cell line harboring EGFRL858R/T790M/C797S with an IC50 of 43.28 nM. Moreover, 52 demonstrated good pharmacokinetic properties and excellent in vivo efficacy. Overall, the compound 52 can be considered a promising candidate for overcoming EGFR C797S-mediated mutations.

Ferritinophagy mediates adaptive resistance to EGFR tyrosine kinase inhibitors in non-small cell lung cancer.

Osimertinib (Osi) is a widely used epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). However, the emergence of resistance is inevitable, partly due to the gradual evolution of adaptive resistant cells during initial treatment. Here, we find that Osi treatment rapidly triggers adaptive resistance in tumor cells. Metabolomics analysis reveals a significant enhancement of oxidative phosphorylation (OXPHOS) in Osi adaptive-resistant cells. Mechanically, Osi treatment induces an elevation of NCOA4, a key protein of ferritinophagy, which maintains the synthesis of iron-sulfur cluster (ISC) proteins of electron transport chain and OXPHOS. Additionally, active ISC protein synthesis in adaptive-resistant cells significantly increases the sensitivity to copper ions. Combining Osi with elesclomol, a copper ion ionophore, significantly increases the efficacy of Osi, with no additional toxicity. Altogether, this study reveals the mechanisms of NCOA4-mediated ferritinophagy in Osi adaptive resistance and introduces a promising new therapy of combining copper ionophores to improve its initial efficacy.

Real-world osimertinib pretreatment experience in patients with epidermal growth factor receptor T790M mutation-positive locally advanced or metastatic non-small cell lung cancer.

Osimertinib has demonstrated efficacy in patients with epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer (NSCLC) in clinical trials. However, real-world data on its effectiveness remain scarce. Taiwanese patients with T790M-positive locally advanced or metastatic NSCLC and progressive disease following treatment with at least one EGFR tyrosine kinase inhibitor (TKI) were enrolled from the osimertinib early access program. Of the 419 patients (mean age, 63 years; female, 67%), 53% were heavily pretreated (≥ third-line [3L]), making osimertinib a fourth-line (4L) intervention. The median progression-free survival (PFS) was 10.5 months (95% confidence interval [CI]: 8.95-11.41); the 18-month PFS rate was 26.5%. The median overall survival (OS) was 19.0 months (95% CI: 16.30-20.95); the 24-month OS rate was 40.9%. The objective response rate was 32.46%, and the disease control rate was 86.38%. The median time to treatment discontinuation of osimertinib monotherapy was 11.9 months (95% CI: 10.49-13.11). Subgroup analyses of median PFS and OS in the chemotherapy combination group vs. the osimertinib monotherapy group yielded no difference. Central nervous system (CNS) metastasis, number of prior lines of therapy, and types of initial EGFR-TKIs did not significantly impact outcomes. The median PFS values were 9.0 (95% CI: 5.18-11.34) and 10.9 (95% CI: 9.18-11.90) months with and without CNS metastasis, respectively, and 10.8 (95% CI: 8.59-12.69), 13.6 (95% CI: 10.89-16.3), and 9.2 (95% CI: 7.8-10.62) months for second-line (2L), 3L, and ≥4L therapy, respectively. In patients who received osimertinib as 2L therapy, the median PFS values in response to prior afatinib, erlotinib and gefitinib treatment were 11.2 (95% CI: 4.85-4.79), 10.5 (95% CI: 8.59-20.26) and 8.7 (95% CI: 7.21-16.79) months, respectively. Overall, real-world data from Taiwan support the clinical benefits of osimertinib in EGFR T790M -positive NSCLC.

Real-World Data on Subsequent Therapy for First-Line Osimertinib-Induced Pneumonitis: Safety of EGFR-TKI Rechallenge (Osi-risk Study TORG-TG2101).

BACKGROUND: Although osimertinib is a promising therapeutic agent for advanced epidermal growth factor receptor (EGFR) mutation-positive lung cancer, the incidence of pneumonitis is particularly high among Japanese patients receiving the drug. Furthermore, the safety and efficacy of subsequent anticancer treatments, including EGFR-tyrosine kinase inhibitor (TKI) rechallenge, which are to be administered after pneumonitis recovery, remain unclear. OBJECTIVE: This study investigated the safety of EGFR-TKI rechallenge in patients who experienced first-line osimertinib-induced pneumonitis, with a primary focus on recurrent pneumonitis. PATIENTS AND METHODS: We retrospectively reviewed the data of patients with EGFR mutation-positive lung cancer who developed initial pneumonitis following first-line osimertinib treatment across 34 institutions in Japan between August 2018 and September 2020. RESULTS: Among the 124 patients included, 68 (54.8%) patients underwent EGFR-TKI rechallenge. The recurrence rate of pneumonitis following EGFR-TKI rechallenge was 27% (95% confidence interval [CI] 17-39) at 12 months. The cumulative incidence of recurrent pneumonitis was significantly higher in the osimertinib group than in the first- and second-generation EGFR-TKI (conventional EGFR-TKI) groups (hazard ratio [HR] 3.1; 95% CI 1.3-7.5; p = 0.013). Multivariate analysis revealed a significant association between EGFR-TKI type (osimertinib or conventional EGFR-TKI) and pneumonitis recurrence, regardless of severity or status of initial pneumonitis (HR 3.29; 95% CI 1.12-9.68; p = 0.03). CONCLUSIONS: Osimertinib rechallenge after initial pneumonitis was associated with significantly higher recurrence rates than conventional EGFR-TKI rechallenge.

Osimertinib in combination with anti-angiogenesis therapy presents a promising option for osimertinib-resistant non-small cell lung cancer.

BACKGROUND: Osimertinib has become standard care for epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients whereas drug resistance remains inevitable. Now we recognize that the interactions between the tumor and the tumor microenvironment (TME) also account for drug resistance. Therefore, we provide a new sight into post-osimertinib management, focusing on the alteration of TME. METHODS: We conducted a retrospective study on the prognosis of different treatments after osimertinib resistance. Next, we carried out in vivo experiment to validate our findings using a humanized mouse model. Furthermore, we performed single-cell transcriptome sequencing (scRNA-seq) of tumor tissue from the above treatment groups to explore the mechanisms of TME changes. RESULTS: Totally 111 advanced NSCLC patients have been enrolled in the retrospective study. The median PFS was 9.84 months (95% CI 7.0-12.6 months) in the osimertinib plus anti-angiogenesis group, significantly longer than chemotherapy (P = 0.012) and osimertinib (P = 0.003). The median OS was 16.79 months (95% CI 14.97-18.61 months) in the osimertinib plus anti-angiogenesis group, significantly better than chemotherapy (P = 0.026), the chemotherapy plus osimertinib (P = 0.021), and the chemotherapy plus immunotherapy (P = 0.006). The efficacy of osimertinib plus anlotinib in the osimertinib-resistant engraft tumors (R-O+A) group was significantly more potent than the osimertinib (R-O) group (P<0.05) in vitro. The combinational therapy could significantly increase the infiltration of CD4+ T cells (P<0.05), CD25+CD4+ T cells (P<0.001), and PD-1+CD8+ T cells (P<0.05) compared to osimertinib. ScRNA-seq demonstrated that the number of CD8+ T and proliferation T cells increased, and TAM.mo was downregulated in the R-O+A group compared to the R-O group. Subtype study of T cells explained that the changes caused by combination treatment were mainly related to cytotoxic T cells. Subtype study of macrophages showed that proportion and functional changes in IL-1ß.mo and CCL18.mo might be responsible for rescue osimertinib resistance by combination therapy. CONCLUSIONS: In conclusion, osimertinib plus anlotinib could improve the prognosis of patients with a progressed disease on second-line osimertinib treatment, which may ascribe to increased T cell infiltration and TAM remodeling via VEGF-VEGFR blockage.

Senolysis of gemcitabine-induced senescent human pancreatic cancer cells.

INTRODUCTION: Gemcitabine (GEM) is often used to treat pancreatic cancer. Many anti-cancer drugs induce cancer cell death, but some cells survive after cell cycle arrest. Such a response to DNA damage is termed cellular senescence. Certain drugs, including the Bcl-2-family inhibitor ABT-263, kill senescent cells; this is termed senolysis. In this study, we examined the therapeutic benefits of ABT-263 in GEM-induced senescence of human pancreatic cancer cells. METHODS AND RESULTS: Of four pancreatic cancer cell lines (PANC-1, AsPC-1, CFPAC-1, and PANC10.05), GEM induced senescent features in PANC-1 and AsPC-1 cells, including increases in the cell sizes and expression levels of mRNAs encoding interleukin (IL)-6/IL-8 and induction of ß-galactosidase. Successive treatment with GEM and ABT-263 triggered apoptosis in PANC-1 and AsPC-1 cells and suppressed colony formation significantly. Senolysis of GEM-induced senescent pancreatic cancer cells by ABT-263 was triggered by a Bcl-xL inhibitor, but not by a Bcl-2 inhibitor, suggesting a central role for Bcl-xL in senolysis. In a xenograft mouse model, combined treatment with GEM and ABT-737 (an ABT-263 analog exhibiting the same specificity) suppressed in vivo growth of AsPC-1 significantly. CONCLUSION: Together, our results indicate that sequential treatment with GEM and senolytic drugs effectively kill human pancreatic cancer cells.

Genome-wide CRISPR screens identify the YAP/TEAD axis as a driver of persister cells in EGFR mutant lung cancer.

Most lung cancer patients with metastatic cancer eventually relapse with drug-resistant disease following treatment and EGFR mutant lung cancer is no exception. Genome-wide CRISPR screens, to either knock out or overexpress all protein-coding genes in cancer cell lines, revealed the landscape of pathways that cause resistance to the EGFR inhibitors osimertinib or gefitinib in EGFR mutant lung cancer. Among the most recurrent resistance genes were those that regulate the Hippo pathway. Following osimertinib treatment a subpopulation of cancer cells are able to survive and over time develop stable resistance. These 'persister' cells can exploit non-genetic (transcriptional) programs that enable cancer cells to survive drug treatment. Using genetic and pharmacologic tools we identified Hippo signalling as an important non-genetic mechanism of cell survival following osimertinib treatment. Further, we show that combinatorial targeting of the Hippo pathway and EGFR is highly effective in EGFR mutant lung cancer cells and patient-derived organoids, suggesting a new therapeutic strategy for EGFR mutant lung cancer patients.

Clinical outcomes in patients with non-small cell lung cancer harboring EGFR Exon20 in-frame insertions in the near-loop and far-loop: Results from LC-SCRUM-Asia.

OBJECTIVES: In this study, we explored the clinical outcomes of non-small cell lung cancer (NSCLC) patients with EGFR Exon20 in-frame insertions (Exon20ins), and the impact of the location of Exon20ins on these clinical outcomes. MATERIALS AND METHODS: The efficacies of current systemic therapies in NSCLC patients harboring Exon20ins were investigated using a large-scale clinico-genomic database of LC-SCRUM-Asia, and compared with that of amivantamab in the CHRYSALIS trial. RESULTS: Of the 11,397 patients enrolled in LC-SCRUM-Asia, Exon20ins were detected in 189 patients (1.7 %). Treatment with classical EGFR tyrosine-kinase inhibitors (classical TKIs) was associated with a significantly shorter progression-free survival (PFS) in NSCLC patients with Exon20ins as compared with Exon19 deletions and L858R. Post platinum-based chemotherapy, classical TKIs and immune checkpoint inhibitors (ICIs) were associated with a shorter PFS than with docetaxel in patients with Exon20ins (HR [95 % CI]; TKIs vs docetaxel, 2.16 [1.35-3.46]; ICIs vs docetaxel, 1.49 [1.21-1.84]). Patients treated with amivantamab in the CHRYSALIS trial showed a risk reduction in PFS and overall survival as compared with LC-SCRUM-Asia patients treated with docetaxel, classical TKIs, or ICIs. Among the 189 patients, Exon20ins were classified as near-loop or far-loop insertions in 115 (61 %) and 56 (30 %) patients, respectively. Treatment with osimertinib was associated with a longer PFS in patients with Exon20ins in near-loop as compared with far-loop (median, 5.6 vs. 2.0 months; HR [95 % CI], 0.22 [0.07-0.64]). CONCLUSIONS: After platinum-based chemotherapy, classical TKIs and ICIs are less effective in NSCLC patients with Exon20ins, and amivantamab may be a promising targeted therapy. There is a possibility that the location of Exon20ins has an impact on the efficacy of TKIs.

Osimertinib plus local treatment for brain metastases versus osimertinib alone in patients with EGFR-Mutant Non-Small Cell Lung Cancer.

OBJECTIVES: Osimertinib is a standard treatment for patients with EGFR-mutant non-small cell lung cancer (NSCLC) and is highly effective for brain metastases (BMs). However, it is unclear whether local treatment (LT) for BMs prior to osimertinib administration improves survival in EGFR-mutant NSCLC. We aimed to reveal the survival benefit of upfront local treatment (LT) for BMs in patients treated with osimertinib. MATERIALS AND METHODS: This multicenter retrospective study included consecutive patients with EGFR mutation (19del or L858R)-positive NSCLC who had BMs before osimertinib initiation between August 2018 and October 2021. We compared overall survival (OS) and central nervous system progression-free survival (CNS-PFS) between patients who received upfront LT for BMs (the upfront LT group), and patients who received osimertinib only (the osimertinib-alone group). Inverse-probability treatment weighting (IPTW) analysis was performed to adjust for potential confounding factors. RESULTS: Of the 121 patients analyzed, 57 and 64 patients had 19del and L858R, respectively. Forty-five and 76 patients were included in the upfront LT group and the osimertinib-alone groups, respectively. IPTW-adjusted Kaplan-Meier curves showed that the OS of the upfront LT group was significantly longer than that of the osimertinib-alone group (median, 95 % confidence intervals [95 %CI]: Not reached [NR], NR-NR vs. 31.2, 21.7-33.2; p = 0.021). The hazard ratio (HR) for OS and CNS-PFS was 0.37 (95 %CI, 0.16-0.87) and 0.36 (95 %CI, 0.15-0.87), respectively. CONCLUSIONS: The OS and CNS-PFS of patients who received upfront LT for BMs followed by osimertinib were significantly longer than those of patients who received osimertinib alone. Upfront LT for BMs may be beneficial in patients with EGFR-mutant NSCLC treated with osimertinib.

[Acute myeloid leukemia with central nervous system involvement successfully treated with gilteritinib].

A 69-year-old woman was referred to our hospital due to hyperleukocytosis. We diagnosed acute myeloid leukemia and started induction therapy with the CAG regimen (aclarubicin, cytarabine and filgrastim). However, the patient was refractory to the initial treatment and developed quadriplegia, and a cerebrospinal fluid (CSF) test showed elevated blasts. We then performed intrathecal chemotherapy, and the number of blasts in CSF gradually decreased. But only two cycles of intrathecal therapy were possible due to severe methotrexate-induced mucositis. The leukemia cells had fms-like kinase 3-internal tandem duplication (FLT3-ITD), so we started treatment with oral gilteritinib. The patient then achieved hematological complete remission. Her paralysis was also resolving, and the CSF was clear of blasts for more than 6 months. Some reports show that gilteritinib may penetrate the CNS, and this case also supports the effectiveness of gilteritinib on CNS leukemia.

Incidence of pleural effusion with dasatinib and the effect of switching therapy to a different TKI in patients with chronic phase CML.

Dasatinib is one of the second generation tyrosine kinase inhibitors (TKI) which is approved for the treatment of patients with chronic phase CML (CP-CML) both in the front line and in the second line setting. Pleural effusion (PE) is a unique toxicity associated with dasatinib use. Our aim was to study the incidence of pleural effusion in our cohort of patients who were treated with dasatinib for CP-CML and the safety upon TKI switch. A total of 390 patients were treated with dasatinib during their course of treatment for CP-CML. A total of 69 patients (17.6%) developed any grade of PE. About 33 (48%) patients developed CTCAE grade 2 PE, 34 (49%) grade 3 and only 1 patient developed grade 4 PE. Recurrence of PE was observed in 34 (49%) patients. While only 12 patients (17.3%) continued using dasatinib after development of PE, dasatinib was discontinued in the other 57 patients. Therapy was switched to bosutinib in 13 patients out of which 6 (46%) patients re-developed PE. While only 12.5% patients developed re-accumulation of pleural fluid in patients switched to imatinib, none of the patients switched to nilotinib re-developed PE. A change in TKI to bosutinib was associated with a 46% risk of recurrence of PE in patients who develop PE on dasatinib for the treatment of CP-CML. The incidence of recurrent PE was markedly lower in patient switched to imatinib or nilotinib.

Furmonertinib and intrathecal pemetrexed chemotherapy rechallenges osimertinib-refractory leptomeningeal metastasis in a non-small cell lung cancer patient harboring EGFR20 R776S, C797S, and EGFR21 L858R compound EGFR mutations: a case report.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are considered the first-line treatment for advanced or metastatic non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. However, due to the rarity of cases, the response of EGFR-TKIs in patients harboring uncommon compound EGFR mutations still needs to be determined. Here, we demonstrated the case of a 47-year-old smoker diagnosed with leptomeningeal metastasis from NSCLC and had EGFR20 R776S, C797S, and EGFR21 L858R compound mutations. He was treated with furmonertinib combined with intrathecal pemetrexed chemotherapy following progression on osimertinib, which led to clinical improvement and successfully prolonged his survival by 3 months. Regrettably, the patient eventually died from heart disease. This report provides the first reported evidence for the use of furmonertinib and intrathecal pemetrexed chemotherapy in NSCLC patients harboring EGFR R776S/C797S/L858R mutations who progressed on previous EGFR-TKIs.

Gilteritinib as Post-Transplant Maintenance for AML With Internal Tandem Duplication Mutation of FLT3.

PURPOSE: Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 (FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit. METHODS: Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS. RESULTS: Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575). CONCLUSION: Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

Outcomes of patients with advanced epithelial growth factor receptor mutant lung cancer treated with first-line osimertinib who would not have met the eligibility criteria for the FLAURA clinical trial.

OBJECTIVES: Osimertinib is largely used as first-line therapy for metastatic epithelial growth factor receptor (EGFR) mutant lung cancers based on the FLAURA clinical trial. Real-world patient outcomes often differ from clinical trial outcomes. This study evaluated the efficacy of first-line osimertinib in patients treated in British Columbia (BC), Canada. Furthermore, we compared the outcomes of patients who would and would not have been eligible for the original FLAURA trial. METHODS: Consecutive patients receiving first-line osimertinib for metastatic EGFR exon19 or L858R lung cancer were identified using the BC Cancer Pharmacy Database. Patient eligibility for the FLAURA clinical trial were retrospectively reviewed based on the following criteria: ECOG ≥ 2, symptomatic brain metastases or on steroids, hemoglobin < 90 g/L, platelets < 100x109/L, or a creatinine clearance < 50 mL/min. mOS was assessed for the entire population and compared between patients who would have been eligible and ineligible for FLAURA. RESULTS: From January 2020 to October 2021, 311 patients received first-line osimertinib; 44 % (137/311) were deemed FLAURA ineligible, predominantly due to low ECOG (n = 120). After a median follow-up of 26.5 months, the mOS for the entire cohort was 27.4 months (95 %CI 23.8-30.1). The mOS for ineligible patients was 18 months shorter than eligible patients (15.8 vs 34.2, p < 0.001). Ineligible patients had higher rates of de novo stage IV disease, higher rates of stage IVB disease, and more sites of disease than eligible patients. CONCLUSION: In this real-world population, nearly half of patients would have been ineligible for FLAURA. The mOS was one year shorter than reported in FLAURA. However, patients who would have been eligible for the FLAURA clinical trial had similar OS to patients enrolled in FLAURA. Trial ineligible patients had a higher burden of disease at baseline which may have led to inferior outcomes. Further research is needed to improve outcomes in these patients.

Deleterious association between proton pump inhibitor and protein kinase inhibitor exposure and survival for patients with lung cancer: A nationwide cohort study.

INTRODUCTION: Previous studies have identified an interaction between protein kinase inhibitors (PKIs) and proton pump inhibitors (PPIs) in patients with lung cancer. This type of interaction may reduce the efficacy of PKIs. However, the effect of PKI-PPI interaction on patient mortality remains controversial. This study set out to determine the impact of PKI-PPI interaction on overall survival for lung cancer patients. MATERIALS AND METHODS: This study was conducted using data from the French National Health Care Database from January 1, 2011 to December 31, 2021. We identified patients with: (i) an age equal to or greater than 18 years; (ii) lung cancer; and (iii) at least one reimbursement for one of the following drugs: erlotinib, gefitinib, afatinib and osimertinib. Patients were followed-up between the first date of PKI reimbursement and either December 31, 2021 or if they died, the date on which death occurred. The cumulative exposure to PPI duration during PKI treatment was calculated as the ratio between the number of concomitant exposure days to PKI and PPI and the number of exposure days to PKI. A survival analysis using a Cox proportional hazards model was then performed to assess the risk of death following exposure to a PKI-PPI interaction. RESULTS: 34,048 patients received at least one reimbursement for PKIs of interest in our study: 26,133 (76.8 %) were exposed to erlotinib; 3,142 (9.2 %) to gefitinib; 1,417 (4.2 %) to afatinib; and 3,356 (9.9 %) to osimertinib. Patients with concomitant exposure to PKI-PPI interaction during 20 % or more of the PKI treatment period demonstrated an increased risk of death (HR, 1.60 [95 % CI, 1.57-1.64]) compared to other patients. When this cut-off varied from 10 % to 80 %, the estimated HR ranged from 1.46 [95 % CI, 1.43-1.50] to 2.19 [95 % CI, 2.12-2.25]. DISCUSSION/CONCLUSION: In our study, an elevated risk of death was observed in patients exposed to PKI-PPI interaction. Finally, we were able to identify a dose-dependent effect for this interaction. This deleterious effect of osimertinib and PPI was revealed for the first time in real life conditions.

Phase I/II Study of Combined BCL-xL and MEK Inhibition with Navitoclax and Trametinib in KRAS or NRAS Mutant Advanced Solid Tumors.

PURPOSE: MEK inhibitors (MEKi) lack monotherapy efficacy in most RAS-mutant cancers. BCL-xL is an anti-apoptotic protein identified by a synthetic lethal shRNA screen as a key suppressor of apoptotic response to MEKi. PATIENTS AND METHODS: We conducted a dose escalation study (NCT02079740) of the BCL-xL inhibitor navitoclax and MEKi trametinib in patients with RAS-mutant tumors with expansion cohorts for: pancreatic, gynecologic (GYN), non-small cell lung cancer (NSCLC), and other cancers harboring KRAS/NRAS mutations. Paired pretreatment and day 15 tumor biopsies and serial cell-free (cf)DNA were analyzed. RESULTS: A total of 91 patients initiated treatment, with 38 in dose escalation. Fifty-eight percent had ≥3 prior therapies. A total of 15 patients (17%) had colorectal cancer, 19 (11%) pancreatic, 15 (17%) NSCLC, and 32 (35%) GYN cancers. The recommended phase II dose (RP2D) was established as trametinib 2 mg daily days 1 to 14 and navitoclax 250 mg daily days 1 to 28 of each cycle. Most common adverse events included diarrhea, thrombocytopenia, increased AST/ALT, and acneiform rash. At RP2D, 8 of 49 (16%) evaluable patients achieved partial response (PR). Disease-specific differences in efficacy were noted. In patients with GYN at the RP2D, 7 of 21 (33%) achieved a PR and median duration of response 8.2 months. No PRs occurred in patients with colorectal cancer, NSCLC, or pancreatic cancer. MAPK pathway inhibition was observed in on-treatment tumor biopsies. Reductions in KRAS/NRAS mutation levels in cfDNA correlated with clinical benefit. CONCLUSIONS: Navitoclax in combination with trametinib was tolerable. Durable clinical responses were observed in patients with RAS-mutant GYN cancers, warranting further evaluation in this population.

Delayed cardiotoxicity following osimertinib therapy in non-small cell lung cancer: a unique case report.

This case report features a 62-year-old male with stage IB lung adenocarcinoma harboring an epidermal growth factor receptor exon 19 deletion, who underwent treatment with osimertinib following a left upper lobectomy and lymph node dissection. Despite a history of smoking and well-managed type 2 diabetes, the patient developed heart failure 18 months post-initiation of osimertinib therapy, marking one of the latest occurrences of heart failure following osimertinib treatment documented in limited literature. Cardiac MRI revealed significant left ventricular enlargement, lateral wall myocardial thinning, and localized myocardial fibrosis without perfusion defects, a finding not previously reported in literature. This case underscores the severe and unusual cardiac effects of osimertinib in patients with latent risk factors, highlighting the importance of vigilant cardiac monitoring and a multidisciplinary management approach.