Concentration-QTc modeling of sitravatinib in patients with advanced solid malignancies.

Sitravatinib (MGCD516) is an orally available, small molecule, tyrosine kinase inhibitor that has been evaluated in patients with advanced solid tumors. Concentration-corrected QT interval (QTc; C-QTc) modeling was undertaken, using 767 matched concentration-ECG observations from 187 patients across two clinical studies in patients with advanced solid malignancies, across a dose range of 10-200 mg, via a linear mixed-effects (LME) model. The effect on heart rate (HR)-corrected QT interval via Fridericia's correction method (QTcF) at the steady-state maximum concentration (Cmax,ss) for the sitravatinib proposed therapeutic dosing regimen (100 mg malate once daily [q.d.]) without and with relevant intrinsic and extrinsic factors were predicted. No significant changes in HR from baseline were observed. Hysteresis between sitravatinib plasma concentration and change in QTcF from baseline (ΔQTcF) was not observed. There was no significant relationship between sitravatinib plasma concentration and ΔQTcF. The final C-QTc model predicted a mean (90% confidence interval [CI]) ΔQTcF of 3.92 (1.95-5.89) ms and 2.94 (0.23-6.10) ms at the proposed therapeutic dosing regimen in patients with normal organ function (best case scenario) and patients with hepatic impairment (worst-case scenario), respectively. The upper bounds of the 90% CIs were below the regulatory threshold of concern of 10 ms. The results of the described C-QTc analysis, along with corroborating results from nonclinical safety pharmacology studies, indicate that sitravatinib has a low risk of QTc interval prolongation at the proposed therapeutic dose of 100 mg malate q.d.

Beneficial effects of maintaining liver function during hepatic arterial infusion chemotherapy combined with tyrosine kinase and programmed cell death protein-1 inhibitors on the outcomes of patients with unresectable hepatocellular carcinoma.

BACKGROUND AND AIM: Combination therapy is the primary treatment for unresectable hepatocellular carcinoma (u-HCC). The hepatic functional reserve is also critical in the treatment of HCC. In this study, u-HCC was treated with combined hepatic arterial infusion chemotherapy (HAIC), tyrosine kinase inhibitors (TKIs), and programmed cell death protein-1 (PD-1) inhibitors to analyze the therapeutic response, progression-free survival (PFS), and safety. METHODS: One hundred sixty-two (162) patients with u-HCC were treated by combination therapy of HAIC, TKIs, and PD-1 inhibitors. PFS was assessed by Child-Pugh (CP) classification subgroups and the change in the CP score during treatment. RESULTS: The median PFS was 11.7 and 5.1 months for patients with CP class A (CPA) and CP class B (CPB), respectively (p = 0.013), with respective objective response rates of 61.1 and 27.8% (p = 0.002) and conversion rates of 16 and 0% (p = 0.078). During treatment, the CP scores in patients with CPA worsened less in those with complete and partial response than in those with stable and progressive disease. In the CP score 5, patients with an unchanged CP score had longer PFS than those with a worsened score (Not reached vs. 7.9 months, p = 0.018). CPB was an independent factor negatively affecting treatment response and PFS. Patients with CPA responded better to the combination therapy and had fewer adverse events (AEs) than those with CPB. CONCLUSIONS: Thus, triple therapy is more beneficial in patients with good liver function, and it is crucial to maintain liver function during treatment.

Post-marketing safety concerns with palbociclib: a disproportionality analysis of the FDA adverse event reporting system.

OBJECTIVES: To explore the association between palbociclib and related adverse events (AEs) in the real world through U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) database. METHODS: The signal strength of palbociclib-related AEs was done by disproportionality analysis. Clinical priority of palbociclib-related AEs was scored and ranked by assessing five different features. Outcome analysis, time to onset analysis, dose-report /AEs number analysis, and stratification analysis were all performed. RESULTS: There were 61,821 'primary suspected (PS)' reports of palbociclib and 195,616 AEs associated with palbociclib. The four algorithms simultaneously detected 18 positive signals at the SOC level, and 65 positive signals at the PT level. Bone marrow failure, neuropathy, peripheral, pleural effusion, myelosuppression, pulmonary edema, and pulmonary thrombosis were also found to have positive signals. Gender (female vs male, χ2 = 5.287, p = 0.022) and age showed significant differences in serious and non-serious reports. Palbociclib-related AEs had a median onset time of 79 days (interquartile range [IQR] 20-264 days). CONCLUSIONS: The study identified potential Palbociclib-related AEs and offered warnings for special AEs, providing further data for palbociclib safety studies in breast cancer patients. Nonetheless, prospective clinical trials are needed to validate these results and explain their relationship.

Tofacitinib Treatment for Pretibial Myxedema.

This case report describes tofacitinib treatment for 2 patients with pretibial myxedema.

Frontline combination of dasatinib and low-intensity chemotherapy in adults with de novo Philadelphia chromosome-positive acute lymphoblastic leukemia.

BACKGROUND: Studies on dasatinib-based low-intensity induction regimens and post-remission strategies are limited in China. Therefore, we conducted a single-center phase 2 trial in newly diagnosed adult patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) to establish the efficacy and safety of this treatment approach. RESEARCH DESIGN AND METHODS: Patients received one month of dasatinib plus low-intensity chemotherapy and two months of dasatinib monotherapy for induction, followed by a single course of high-dose methotrexate for consolidation. Subsequently, they underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) or tyrosine kinase inhibitor (TKI)-based treatment for maintenance therapy between October 2015 and August 2022. RESULTS: Twenty-two patients were enrolled. Median age was 45 years (range, 20-71). The rates of major and complete molecular responses in the third month were 18.2% and 40.9% respectively. With a median follow-up of 15 months (range, 5-89), the estimated 3-year disease-free survival (DFS) and overall survival (OS) were 52.4% and 73.2%, respectively. The TKI-based cohort had a significantly poorer DFS (p = 0.014) and OS (p = 0.008) than the allo-HSCT cohort. CONCLUSIONS: Our results suggest that dasatinib-based low-intensity chemotherapy is safe and effective as an induction strategy in the Chinese population. Allo-HSCT plays a crucial role in the long-term outcomes of patients with Ph+ ALL. CLINICAL TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov as NCT02690922.

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.

Predicting drug-drug interactions in breast cancer patients treated with CDK4/6 inhibitors and forward planning.

INTRODUCTION: Cyclin-dependent kinase (CDK) 4/6 inhibitors are cornerstones in the treatment of Hormone Receptor (HR) positive and Human Epidermal Growth factor (HER2) negative metastatic breast cancer. Given their widespread use in the metastatic setting and emerging use in the adjuvant setting, studying drug-drug interactions (DDI) of these medications is of utmost importance. AREAS COVERED: This review provides key background information on the CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib. We discuss drug-drug interactions including those with proton pump inhibitors as well as CYP3A substrates, inhibitors, and inducers. We describe the effect of these drugs on membrane transporters and their substrates as well as those drugs that increase risk of CDK4/6 toxicities. Finally, we explore future directions for strategies to minimize drug-drug interactions. EXPERT OPINION: It is crucial to be mindful of medications that may interfere with drug absorption, such as proton pump inhibitors, as well as those that interfere with drug metabolism, such as CYP3A4 inhibitors and inducers. Additionally, special consideration should be given to populations at higher risk for polypharmacy, such as older patients with greater comorbidities. These interactions and patient characteristics should be considered when developing individual treatment plans with CDK4/6 inhibitors.

Outcomes, responses, and prognostic analyses of intrathecal combined treatment for leptomeningeal metastasis from lung adenocarcinoma.

BACKGROUND: Leptomeningeal metastasis (LM) is a severe lung cancer complication, with potentially fatal consequences. The use of intrathecal therapy (IT) combined with systemic therapy has shown promise as a treatment approach for LM. Thus, this study aimed to evaluate the features and responses to IT combined therapy and identify determinants affecting patients with leptomeningeal metastasis resulting from lung adenocarcinoma (LM-LA). METHODS: A retrospective analysis of medical records from our hospital database was performed, covering from April 2018 to August 2022, for 37 patients diagnosed with LM-LA and treated with IT combined therapy. Patients who received IT combined therapy for LM-LA were evaluated for demographic characteristics, treatment efficacy, survival, and variables that impacted them. RESULTS: The median overall survival (mOS) of 37 patients was 16.0 months, and the survival rates at 6 and 12 months were 75.7% and 35.1%, respectively. Among the 21 patients with LM-LA who received IT combined with tyrosine kinase inhibitors (TKIs), the mOS was 17.0 months, which was significantly longer than that of patients treated with IT combined with chemotherapy (7.0 months, P = 0.010) and the best supportive care (6.0 months, P = 0.001). However, no significant survival benefit was observed in patients treated with IT combined with TKIs when compared with those treated with IT combined with PD-1 (5.0 months, P = 0.249). Multivariate analysis indicated that the combination of TKIs was an independent favorable prognostic factor for patients with LM-LA. CONCLUSION: Combination treatment is regarded as an additional option for patients with LM-LA. Compared with other combination therapies in our study, IT combined with TKI therapy provided a better survival outcome for patients with LM-LA.

Cabozantinib monotherapy for advanced adrenocortical carcinoma: a single-arm, phase 2 trial.

BACKGROUND: Adrenocortical carcinoma is a rare malignancy with poor response to systemic chemotherapy. Mitotane is the only approved therapy for adrenocortical carcinoma. Cabozantinib is a multikinase inhibitor approved in multiple malignancies. This is the first prospective trial to explore the anti-tumour activity, safety, and pharmacokinetic profile of cabozantinib in patients with advanced adrenocortical carcinoma. METHODS: This investigator-initiated, single-arm, phase 2 trial in adult patients (aged ≥18 years) with advanced adrenocortical carcinoma was done at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Eligible patients had histologically confirmed adrenocortical carcinoma, were not candidates for surgery with curative intent, had measurable disease, had an estimated life expectancy of at least 3 months, and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 with adequate organ function. Patients who had used mitotane within 6 months of study participation were required to have a serum mitotane level of less than 2 mg/L. Patients were given oral cabozantinib 60 mg daily with the option of dose reduction to manage adverse events. The primary endpoint was progression-free survival at 4 months, assessed in all patients who received at least one dose of study drug per protocol. This study is registered with ClinicalTrials.gov, NCT03370718, and is now complete. FINDINGS: Between March 1, 2018, and May 31, 2021, we enrolled 18 patients (ten males and eight females), all of whom received at least one dose of study treatment. Of the 18 patients, eight (44%) had an ECOG performance status of 0, nine (50%) patients had a performance status of 1, and one (6%) patient had a performance status of 2. Median follow-up was 36·8 months (IQR 30·2-50·3). At 4 months, 13 (72·2%; 95% CI 46·5-90·3) of 18 patients had progression-free survival and median progression-free survival was 6 months (95% CI 4·3 to not reached). One patient remains on treatment. Treatment-related adverse events of grade 3 or worse occurred in 11 (61%) of 18 patients. The most common grade 3 adverse events were lipase elevation (three [17%] of 18 patients), elevated γ-glutamyl transferase concentrations (two [11%] patients), elevated alanine aminotransferase concentrations (two [11%] patients), hypophosphatemia (two [11%] patients), and hypertension (two [11%] patients). One (6%) of 18 patients had grade 4 hypertension. No treatment related deaths occurred on study. INTERPRETATION: Cabozantinib in advanced adrenocortical carcinoma showed promising efficacy with a manageable and anticipated safety profile. Further prospective studies with cabozantinib alone and in combination with immune checkpoint therapy are ongoing. FUNDING: Exelixis.

Necroptosis blockade prevents lung injury in severe influenza.

Severe influenza A virus (IAV) infections can result in hyper-inflammation, lung injury and acute respiratory distress syndrome1-5 (ARDS), for which there are no effective pharmacological therapies. Necroptosis is an attractive entry point for therapeutic intervention in ARDS and related inflammatory conditions because it drives pathogenic lung inflammation and lethality during severe IAV infection6-8 and can potentially be targeted by receptor interacting protein kinase 3 (RIPK3) inhibitors. Here we show that a newly developed RIPK3 inhibitor, UH15-38, potently and selectively blocked IAV-triggered necroptosis in alveolar epithelial cells in vivo. UH15-38 ameliorated lung inflammation and prevented mortality following infection with laboratory-adapted and pandemic strains of IAV, without compromising antiviral adaptive immune responses or impeding viral clearance. UH15-38 displayed robust therapeutic efficacy even when administered late in the course of infection, suggesting that RIPK3 blockade may provide clinical benefit in patients with IAV-driven ARDS and other hyper-inflammatory pathologies.

A Phase I Study of KIN-3248, an Irreversible Small-molecule Pan-FGFR Inhibitor, in Patients with Advanced FGFR2/3-driven Solid Tumors.

PURPOSE: Despite efficacy of approved FGFR inhibitors, emergence of polyclonal secondary mutations in the FGFR kinase domain leads to acquired resistance. KIN-3248 is a selective, irreversible, orally bioavailable, small-molecule inhibitor of FGFR1-4 that blocks both primary oncogenic and secondary kinase domain resistance FGFR alterations. EXPERIMENTAL DESIGN: A first-in-human, phase I study of KIN-3248 was conducted in patients with advanced solid tumors harboring FGFR2 and/or FGFR3 gene alterations (NCT05242822). The primary objective was determination of MTD/recommended phase II dose (RP2D). Secondary and exploratory objectives included antitumor activity, pharmacokinetics, pharmacodynamics, and molecular response by circulating tumor DNA (ctDNA) clearance. RESULTS: Fifty-four patients received doses ranging from 5 to 50 mg orally daily across six cohorts. Intrahepatic cholangiocarcinoma (48.1%), gastric (9.3%), and urothelial (7.4%) were the most common tumors. Tumors harbored FGFR2 (68.5%) or FGFR3 (31.5%) alterations-23 (42.6%) received prior FGFR inhibitors. One dose-limiting toxicity (hypersensitivity) occurred in cohort 1 (5 mg). Treatment-related, adverse events included hyperphosphatemia, diarrhea, and stomatitis. The MTD/RP2D was not established. Exposure was dose proportional and concordant with hyperphosphatemia. Five partial responses were observed; 4 in FGFR inhibitor naïve and 1 in FGFR pretreated patients. Pretreatment ctDNA profiling confirmed FGFR2/3 alterations in 63.3% of cases and clearance at cycle 2 associated with radiographic response. CONCLUSION: The trial was terminated early for commercial considerations; therefore, RP2D was not established. Preliminary clinical data suggest that KIN-3248 is a safe, oral FGFR1-4 inhibitor with favorable pharmacokinetic parameters, though further dose escalation was required to nominate the MTD/RP2D. SIGNIFICANCE: KIN-3248 was a rationally designed, next generation selective FGFR inhibitor, that was effective in interfering with both FGFR wild-type and mutant signaling. Clinical data indicate that KIN-3248 is safe with a signal of antitumor activity. Translational science support the mechanism of action in that serum phosphate was proportional with exposure, paired biopsies suggested phospho-ERK inhibition (a downstream target of FGFR2/3), and ctDNA clearance may act as a RECIST response surrogate.

Successful treatment with selpercatinib after pralsetinib-related pneumonitis and intracranial failure in a patient with RET-rearranged nonsmall cell lung cancer.

Pralsetinib and selpercatinib are two highly potent and selective rearranged during transfection (RET) inhibitors that substantially improved the clinical outcome of patients with RET-rearranged non-small cell lung cancer. Treatment with one RET inhibitor after failure of the other is generally not recommended because of cross-resistance mechanisms. We report the case of a patient affected by metastatic RET-rearranged non-small cell lung cancer who experienced long-lasting disease control with pralsetinib. After 13 months from treatment start, the patient developed recurrent drug-related pneumonitis, requiring temporary interruptions and dose reductions and eventually failing to control the disease. Selpercatinib was then started as an off-label treatment, allowing both clinical and radiological intracranial disease control. Selpercatinib was well-tolerated at full dosage, and no pulmonary event occurred. In our case report, after pralsetinib dose reduction due to pulmonary toxicity, the therapeutic switch to selpercatinib allowed the patient to receive a full-dose treatment, eventually restoring disease control. Our case report and a few literature data suggest that switching from pralsetinib to selpercatinib may represent a therapeutic opportunity, especially for patients with brain metastases.

First-in-human phase I study of BEBT-109 in previously treated EGFR exon 20 insertion-mutated advanced non-small cell lung cancer.

BACKGROUND: BEBT-109 is an oral pan-mutant-selective inhibitor of epidermal growth factor receptor (EGFR) that demonstrated promising antitumor potency in preclinical models. METHODS: This first-in-human study was a single-arm, open-label, two-stage study. Phase Ia dose-escalation study evaluated the safety and pharmacokinetics of BEBT-109 in 11 patients with EGFR T790M-mutated advanced non-small cell lung cancer (aNSCLC). Phase Ib dose-expansion study evaluated the safety and efficacy of BEBT-109 in 18 patients with EGFR exon 20 insertion (ex20ins)-mutated treatment-refractory aNSCLC. The primary outcomes were adverse events and antitumor activity. Clinical trial registration number CTR20192575. FINDINGS: The phase Ia study demonstrated no dose-limiting toxicity, no observation of the maximum tolerated dose, and no new safety signals with BEBT-109 in the dose range of 20-180 mg/d, suggesting that BEBT-109 had an acceptable safety profile among patients with EGFR T790M-mutated aNSCLC. Plasma pharmacokinetics of BEBT-109 showed a dose-proportional increase in the area under the curve and maximal concentration, with no significant drug accumulation. The dose-expansion study demonstrated that BEBT-109 treatment was tolerable across the three dose levels. The three most common treatment-related adverse events were diarrhea (100%; 22.2% ≥Grade 3), rash (66.7%; 5.6% ≥Grade 3), and anemia (61.1%; 0% ≥Grade 3). The objective response rate was 44.4% (8 of 18). Median progression-free survival was 8.0 months (95% confidence intervals, 1.33-14.67). CONCLUSION: Preliminary findings showed that BEBT-109 had an acceptable safety profile and favorable antitumor activity in patients with refractory EGFR ex20ins-mutated aNSCLC. FUNDING: National Natural Science Foundation of China.

Comparative efficacy and safety of cabozantinib for malignant tumors: a systematic review and meta-analysis.

OBJECTIVES: To provide a more comprehensive understanding of the efficacy and safety profile of cabozantinib versus placebo in malignant tumors, we conducted a systematic review and meta-analysis. This involved analyzing a collection of published randomized controlled trials to assess the outcomes. METHODS: We used RevMan5.3 software to evaluate the outcomes of the collected studies. The primary outcome we focused on was progression-free survival (PFS), and the secondary outcomes included overall survival (OS) and disease control rate (DCR). RESULTS: Our findings revealed that compared to placebo, cabozantinib significantly extended the PFS of patients [hazard ratios (HR) 0.37, 95% confidence intervals (CI): 0.32, 0.43, p < 0.00001]. Additionally, cabozantinib improved the OS of patients [HR 0.78, 95%CI: 0.68, 0.91, p = 0.002]. While it is important to note that cabozantinib was associated with a higher likelihood of causing digestive, cutaneous, and cardiovascular related adverse events [relative risk (RR) 4.40, 95% CI: 3.10, 6.25, p < 0.00001]. CONCLUSION: Based on our analysis, cabozantinib significantly prolonged the PFS and OS of patients with malignant tumors (p < 0.01). We recommend the use of cabozantinib in treating advanced malignant tumors. However, it is important to continuously monitor and manage the drug-related adverse events. REGISTRATION: PROSPERO (No. CRD42023449261).

Radiation Recall Dermatitis With Bruton Tyrosine Kinase Inhibitor Therapy.

This case report describes a woman in her 70s with a history of breast cancer and chronic lymphocytic leukemia who presented with a painful rash of the bilateral chest extending onto the flanks.

Metabolism, toxicity and management of fruquintinib: a novel drug for metastatic colorectal cancer.

INTRODUCTION: Colorectal cancer (CRC) is the third most diagnosed cancer globally and despite therapeutic strides, the prognosis for patients with metastatic disease (mCRC) remains poor. Fruquintinib is an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI) targeting VEGFR -1, -2, and -3, and has recently received approval by the U.S. Food and Drug Administration for treatment of mCRC refractory to standard chemotherapy, anti-VEGF therapy, and anti-epidermal growth factor receptor (EGFR) therapy. AREAS COVERED: This article provides an overview of the pre-clinical data, pharmacokinetics, clinical efficacy, and safety profile of fruquintinib, as well as the management of clinical toxicities associated with fruquintinib. EXPERT OPINION: Fruquintinib is a valuable additional treatment option for patients with refractory mCRC. The pivotal role of vigilant toxicity management cannot be understated. While fruquintinib offers a convenient and overall, well-tolerated treatment option, ongoing research is essential to determine its efficacy in different patient subsets, evaluate it in combination with chemotherapy and immunotherapy, and determine its role in earlier lines of therapy.

A real-world pharmacovigilance study of FDA Adverse Event Reporting System (FAERS) events for Bruton's tyrosine kinase inhibitors (BTKis) single and its combination therapy.

BACKGROUND: Bruton's tyrosine kinase inhibitors (BTKis) are targeted treatments for B-cell tumors but have significant side effects. This study assesses and contrasts the side effects of BTKis alone and its four combination therapies. RESEARCH DESIGN AND METHODS: The reporting odds ratio (ROR) was used to analyze the data on three BTKis monotherapies and combinations of ibrutinib with rituximab, obinutuzumab, venetoclax, and lenalidomide in the FDA Adverse Event Reporting System (FAERS) database up to December 2022. RESULTS: We analyzed the top 20 PTs for each treatment regimen. In monotherapies, atrial fibrillation (ROR (95% CI): 9.88 (9.47-10.32)) in zanubrutinib and rash (6.97 (5.42-8.98)) in acalabrutinib had higher associations. In combinations, infection (6.86 (6.11-7.70)), atrial fibrillation (27.96 (22.61-34.58)) and myelosuppression (10.09 (8.89-11.46)) were vital signals when ibrutinib was combined with obinutuzumab, and pyrexia (4.22 (2.57-6.93)) had a high signal value when combined with lenalidomide. Hemorrhage had a lower signal value when combined with venetoclax compared to ibrutinib alone (2.50 (2.18-2.87) vs 3.60 (3.52-3.68)). CONCLUSIONS: The ibrutinib-obinutuzumab combo has the highest risk of infection, atrial fibrillation, and myelosuppression, and the ibrutinib-lenalidomide combo has the highest risk of pyrexia. However, the ibrutinib-venetoclax combo has a lower risk of hemorrhage than monotherapy.

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.

Clinical, radiological and molecular responses to combination chemotherapy with MAPK pathway inhibition in relapsed and refractory Langerhans cell histiocytosis.

Optimal therapeutic approaches for advanced Langerhans cell histiocytosis (LCH) are not known. We assessed the safety and efficacy of combined chemotherapy with MAPK pathway inhibition in 10 patients with refractory systemic disease and/or LCH-associated neurodegeneration. Overall response rate was 9/10 (90%) for the entire cohort: 5/5 (100%) for patients with systemic disease and 6/7 (86%) for patients with central nervous system disease. BRAFV600E+ peripheral blood fraction decreased in 5/6 (83%). Toxicities included fever, skin rash, myalgias, neuropathy, cytopenias and hypocalcaemia. Prospective trials are required to optimize combination strategies, determine potential to achieve cure and compare outcomes to chemotherapy or MAPK inhibitor monotherapy.