Search

Gemcitabina; Cáncer avanzado Gemcitabina; Càncer avançat Gemcitabine; Advanced cancer Purpose: This was a Phase I/II trial of the novel checkpoint kinase 1 (Chk1) inhibitor SRA737 given in combination with gemcitabine. Its objectives were to establish the safety profile, recommended Phase 2 dose (RP2D), pharmacokinetics profile, and clinical activity of SRA737. Patients and Methods: Patients with advanced solid tumors were enrolled into dose-escalation cohorts and treated in 28-day cycles with oral SRA737 on days 2, 3, 9, 10, 16, and 17, and intravenous gemcitabine on days 1, 8, and 15. Treatment was continued until progression. Each expansion cohort included up to 20 patients with specific genetically defined tumors. Results: The RP2D was determined to be 500 mg SRA737 combined with low-dose (250 mg/m2) gemcitabine. Of 143 enrolled patients, 77 were treated at doses of at least 500 mg SRA737 combined with 250 mg/m2 gemcitabine. Common toxicities of nausea, vomiting, fatigue, and diarrhea were primarily mild to moderate, and rarely led to treatment discontinuation. Anemia, neutropenia, and thrombocytopenia were grade ≥3 in 11.7%, 16.7%, and 10% of patients treated at the RP2D, respectively. The objective response rate (ORR) was 10.8% overall and notably the ORR in anogenital cancer was 25%. Partial tumor responses were observed in anogenital cancer, cervical cancer, high-grade serous ovarian cancer, rectal cancer, and small cell lung cancer. Conclusions: SRA737 in combination with low-dose gemcitabine was well tolerated with lower myelotoxicity than has been seen at standard doses of gemcitabine or with other combinations of Chk1 inhibitors with gemcitabine. Tumor responses were observed in anogenital and other solid tumors. The trial was sponsored by Sierra Oncology, Inc. Medical writing support was provided by Tina Ippolito, an independent consultant funded by Sierra Oncology. Andrew Dye, an employee of Sierra Oncology, also provided medical writing support and data curation. Bryan Strouse, an employee of Sierra Oncology, also contributed to data curation for this report. UK clinical trial sites acknowledge infrastructural funding from the Experimental Cancer Medical Center and National Institute of Health and Care Research Biomedical Research Centers. The ICR/RMH in addition acknowledges Cancer Research UK funding to Cancer Centre Funding and funding to the Cancer Therapeutics Unit. U. Banerji is a recipient of the NIHR RP-2016–07–028. The publication costs of this article were defrayed in part by the payment of publication fees. Therefore, and solely to indicate this fact, this article is hereby marked “advertisement” in accordance with 18 USC section 1734.

Background Advanced gastro-oesophageal cancer (GEA) treatment has been improved by the introduction of immune checkpoint inhibitors (CPIs), yet identifying predictive biomarkers remains a priority, particularly in patients with a combined positive score (CPS) Design Through integrative transcriptomic and clinicopathological analyses, we studied in both a retrospective and a prospective cohort, the immune tumour microenvironment features. We analysed the cell types composing the immune infiltrate highlighting their functional activity. Results This integrative study allowed the identification of four different groups across our patients. Among them, we identified a cluster whose tumours expressed the most gene signatures related to immunomodulatory pathways and immunotherapy response. These tumours presented an enriched immune infiltrate showing high immune function activity that could potentially achieve the best benefit from CPIs. Finally, our findings were proven in an external CPI-exposed population, where the use of our transcriptomic results combined with CPS helped better identify those patients who could benefit from immunotherapy than using CPS alone (p = 0.043). Conclusions This transcriptomic classification could improve precision immunotherapy for GEA.

Preclinical studies have demonstrated synergy between PARP and PI3K/AKT pathway inhibitors in BRCA1 and BRCA2 (BRCA1/2)–deficient and BRCA1/2-proficient tumors. We conducted an investigator-initiated phase I trial utilizing a prospective intrapatient dose- escalation design to assess two schedules of capivasertib (AKT inhibitor) with olaparib (PARP inhibitor) in 64 patients with advanced solid tumors. Dose expansions enrolled germline BRCA1/2-mutant tumors, or BRCA1/2 wild-type cancers harboring somatic DNA damage response (DDR) or PI3K–AKT pathway alterations. The combination was well tolerated. Recommended phase II doses for the two schedules were: olaparib 300 mg twice a day with either capivasertib 400 mg twice a day 4 days on, 3 days off, or capivasertib 640 mg twice a day 2 days on, 5 days off. Pharmacokinetics were dose proportional. Pharmacodynamic studies confirmed phosphorylated (p) GSK3β suppression, increased pERK, and decreased BRCA1 expression. Twenty-five (44.6%) of 56 evaluable patients achieved clinical benefit (RECIST complete response/partial response or stable disease ≥ 4 months), including patients with tumors harboring germline BRCA1/2 mutations and BRCA1/2 wild-type cancers with or without DDR and PI3K–AKT pathway alterations.Significance:In the first trial to combine PARP and AKT inhibitors, a prospective intrapatient dose- escalation design demonstrated safety, tolerability, and pharmacokinetic–pharmacodynamic activity and assessed predictive biomarkers of response/resistance. Antitumor activity was observed in patients harboring tumors with germline BRCA1/2 mutations and BRCA1/2 wild-type cancers with or without somatic DDR and/or PI3K–AKT pathway alterations.This article is highlighted in the In This Issue feature, p. 1426

Supplementary Tables 1-7; Supplementary Figures 1-2; Supplementary Methods

Supplementary Table S1. IC50 values of ipatasertib on cell viability in cell lines with or without alterations in PTEN or PIK3CA. Supplementary Table S2. Percent tumor growth inhibition (%TGI) in xenograft models with or without alterations in PTEN or PIK3CA. Supplementary Table S3. PI3K/Akt pathway status in archival tumors. Supplementary Table S4. Reasons for discontinuation of study. Supplementary Table S5. Common adverse events for ipatasertib in {greater than or equal to} 10% of patients in any presented group. Supplementary Table S6. All Grade {greater than or equal to} 3 adverse events related to ipatasertib. Supplementary Table S7. Hemoglobin A1C (HgbA1C) values for patients who had both pre-treatment and post-treatment values in Stages 1 and 2. Supplementary Table S8. Summary data for patients with best radiographic stable disease (SD) by RECIST version 1.0 criteria. Supplementary Figure S1. Exposure plots confirm that exposures achieved in patients in the dose-escalation stage (right side) correlated with exposures in preclinical models at TGI90 (left side). Supplementary Figure S2. Relationship between exposure of ipatasertib to the most common ipatasertib-related AEs of fatigue, diarrhea, nausea, and rash. Supplementary Figure S3. Suppression of pGSK3β in platelet-rich plasma versus ipatasertib concentrations. Supplementary Figure S4. Pharmacodynamic (PD) dose-dependent elevations in glucose and insulin following treatment with ipatasertib.

Purpose: Aurora A kinase (AAK) is a key regulator of mitosis and a target for anticancer drug development. This phase I study investigated the safety, pharmacokinetics, and pharmacodynamics of MLN8237 (alisertib), an investigational, oral, selective AAK inhibitor, in 59 adults with advanced solid tumors.Experimental Design: Patients received MLN8237 once daily or twice daily for 7, 14, or 21 consecutive days, followed by 14 days recovery, in 21-, 28-, or 35-day cycles. Dose-limiting toxicities (DLT) and the maximum-tolerated dose (MTD) for the 7- and 21-day schedules were determined. Pharmacokinetic parameters were derived from plasma concentration–time profiles. AAK inhibition in skin and tumor biopsies was evaluated and antitumor activity assessed.Results: Neutropenia and stomatitis were the most common DLTs. The MTD for the 7- and 21-day schedules was 50 mg twice daily and 50 mg once daily, respectively. MLN8237 absorption was fast (median time to maximum concentration, 2 hours). Mean terminal half-life was approximately 19 hours. At steady state, pharmacodynamic effects were shown by accumulation of mitotic and apoptotic cells in skin, and exposure-related increases in numbers of mitotic cells with characteristic spindle and chromosomal abnormalities in tumor specimens, supporting AAK inhibition by MLN8237. Stable disease was observed and was durable with repeat treatment cycles, administered over 6 months, in 6 patients, without notable cumulative toxicity.Conclusions: The recommended phase II dose of MLN8237 is 50 mg twice daily on the 7-day schedule, which is being evaluated further in a variety of malignancies, including in a phase III trial in peripheral T-cell lymphoma. Clin Cancer Res; 18(17); 4764–74. ©2012 AACR.

Supplementary Table 1. Hits from the dalotuzumab enhancer screen. Supplementary Table 2. Patient and disease characteristics. Supplementary Table 3. Summary of dose-limiting toxicities. Supplementary Table 4. Summary of clinical efficacy in breast cancer patients.

PDF file 155K, Principal component analysis (PCA) of the ten biomarkers provides a biomarker profile for each cell line

PDF file 285K, Biomarker validation by Western blot

PDF file 252K, In vivo pharmacodynamic IHC-based biomarker dose-response quantifications

PDF file, 92K, Supplementary Table S1. Summary of pharmacokinetic parameters for MLN8237 once-daily dosing on the 7-day schedule. Supplementary Table S2. Summary of pharmacokinetic parameters for MLN8237 once-daily dosing on the 14-day schedule. Supplementary Table S3. Summary of pharmacokinetic parameters for MLN8237 once-daily dosing on the 21-day schedule. Supplementary Table S4. Summary of pharmacokinetic parameters for MLN8237 twice-daily dosing on the 7-day schedule.

PDF file, 2004K, Figure S2. Changes in skin mitotic index on days 7, 14 and 21.

PDF file 64K, Unsupervised clustering of the core biomarker modulation in cell lines, xenograft tumors, and in tumors from three patients in the 100mg cohort

Supplementary Figure 1. Occurence of infection during treatment with single agent PI3K-AKT-mTOR inhibitors

Supplementary Figure 1. Treatment and pharmacodynamic assessment schedules.

Purpose: Mammalian target of rapamycin (mTOR) inhibition activates compensatory insulin–like growth factor receptor (IGFR) signaling. We evaluated the ridaforolimus (mTOR inhibitor) and dalotuzumab (anti-IGF1R antibody) combination.Experimental Design:In vitro and in vivo models, and a phase I study in which patients with advanced cancer received ridaforolimus (10–40 mg/day every day × 5/week) and dalotuzumab (10 mg/kg/week or 7.5 mg/kg/every other week) were explored.Results: Preclinical studies demonstrated enhanced pathway inhibition with ridaforolimus and dalotuzumab. With 87 patients treated in the phase I study, main dose-limiting toxicities (DLT) of the combination were primarily mTOR-related stomatitis and asthenia at doses of ridaforolimus lower than expected, suggesting blockade of compensatory pathways in normal tissues. Six confirmed partial responses were reported (3 patients with breast cancer); 10 of 23 patients with breast cancer and 6 of 11 patients with ER+/high-proliferative breast cancer showed antitumor activity.Conclusions: Our study provides proof-of-concept that inhibiting the IGF1R compensatory response to mTOR inhibition is feasible with promising clinical activity in heavily pretreated advanced cancer, particularly in ER+/high-proliferative breast cancer (ClinicalTrials.gov identifier: NCT00730379). Clin Cancer Res; 21(1); 49–59. ©2014 AACR.

Primers obtained from PrimerBank database.

PDF file 168K, Pearson and Spearman correlation with survival fraction for all cell lines together or individual cell lines

XLS file 37K, RPPA quantification of laser captured microscopy needle biopsies in patients from the 100mg cohort

Purpose: The oncogenic PI3K/Akt/mTOR pathway is an attractive therapeutic target in cancer. However, it is unknown whether the pathway blockade required for tumor growth inhibition is clinically achievable. Therefore, we conducted pharmacodynamic studies with GDC-0068, an ATP competitive, selective Akt1/2/3 inhibitor, in preclinical models and in patients treated with this compound.Experimental Design: We used a reverse phase protein array (RPPA) platform to identify a biomarker set indicative of Akt inhibition in cell lines and human-tumor xenografts, and correlated the degree of pathway inhibition with antitumor activity. Akt pathway activity was measured using this biomarker set in pre- and post-dose tumor biopsies from patients treated with GDC-0068 in the dose escalation clinical trial.Results: The set of biomarkers of Akt inhibition is composed of 10 phosphoproteins, including Akt and PRAS40, and is modulated in a dose-dependent fashion, both in vitro and in vivo. In human-tumor xenografts, this dose dependency significantly correlated with tumor growth inhibition. Tumor biopsies from patients treated with GDC-0068 at clinically achievable doses attained a degree of biomarker inhibition that correlated with tumor growth inhibition in preclinical models. In these clinical samples, compensatory feedback activation of ERK and HER3 was observed, consistent with preclinical observations.Conclusion: This study identified a set of biomarkers of Akt inhibition that can be used in the clinical setting to assess target engagement. Here, it was used to show that robust Akt inhibition in tumors from patients treated with GDC-0068 is achievable, supporting the clinical development of this compound in defined patient populations. Clin Cancer Res; 19(24); 6976–86. ©2013 AACR.

Tolerability of molecularly targeted agents (MTA) used in cancer therapeutics is determined in phase I trials. We reviewed the reported incidence of toxicity in phase III trials at doses and schedules recommended by phase I trials to evaluate whether these recommendations are realistic when drugs are used in larger populations of patients. We systematically reviewed a safety profile of small molecule (SM-MTA) and mAb MTA (MA-MTA) approved by the FDA in the last 12 years. There was a significantly increased percentage of grade 3 or 4 adverse events reported with SM-MTA compared with MA-MTA [40% vs. 27%; RR 1.5; 95% confidence interval (CI), 1.10–2.25, P = 0.038] in phase III studies. Importantly, a substantial proportion of patients (45%) treated with SM-MTA required dose modifications due to drug-related toxicity in phase III trials. However, this toxicity was associated to a definitive study drug discontinuation in only 9%. Overall, 25% of SM-MTA declared recommended phase II doses below MTD based on pharmacokinetic–pharmacodynamic data and these trials were associated with a significantly reduced number of dose modifications in registration trials (32% vs. 50%; RR 0.64; 95% CI, 0.43–0.88, P = 0.01). Tolerability is going to come into further focus due to the need for combinations of SM-MTA and other anticancer agents. There was a higher incidence of grade 3–4 toxicity in phase III trials in combinations versus single-agent SM-MTAs (64% vs. 37%; RR 1.73; 95% CI, 1.3–2.3, P = 0.001). These results indicate that phase I studies underestimate toxicity while recommending doses of SM-MTA. Clin Cancer Res; 22(9); 2127–32. ©2015 AACR.

PDF file, 55K.

Supplementary Figure 3. Change in Ki67 levels with ridaforolimus and dalotuzumab combination therapy

PDF file 161K, Tumor PIK3CA and PTEN status

Supplementary Data from Circulating Tumor DNA in Stage III Colorectal Cancer, beyond Minimal Residual Disease Detection, toward Assessment of Adjuvant Therapy Efficacy and Clinical Behavior of Recurrences

NRF2 expression analysed by Western Blot after subcellular fractionation.

Purpose: Novel antitumor therapies against the PI3K–AKT–mTOR pathway are increasingly used to treat cancer, either as single agents or in combination with chemotherapy or other targeted therapies. Although these agents are not known to be myelosuppressive, an increased risk of infection has been reported with rapamycin analogues. However, the risk of infection with new inhibitors of this pathway such as PI3K, AKT, mTORC 1/2, or multikinase inhibitors is unknown.Experimental Design: In this retrospective case–control study, we determined the incidence of infection in a group of 432 patients who were treated on 15 phase I clinical trials involving PI3K–AKT–mTOR pathway inhibitors (cases) versus a group of 100 patients on 10 phase I clinical trials of single agent non-PI3K–AKT–mTOR pathway inhibitors (controls) which did not involve conventional cytotoxic agents. We also collected data from 42 patients who were treated with phase I trials of combinations of PI3K–AKT–mTOR inhibitors and MEK inhibitors and 24 patients with combinations of PI3K–AKT–mTOR inhibitors and cytotoxic chemotherapies.Results: The incidence of all grade infection was significantly higher with all single-agent PI3K–AKT–mTOR inhibitors compared with the control group [27% vs. 8%, respectively, OR, 4.26; 95% confidence intervals (CI), 1.9–9.1, P = 0.0001]. The incidence of grade 3 and 4 infection was also significantly higher with PI3K–AKT–mTOR inhibitors compared with the control group (10.3% vs. 3%, OR, 3.74; 95% CI, 1.1–12.4; P = 0.02). Also, the combination of PI3K–AKT–mTOR inhibitors and chemotherapy was associated with a significantly higher incidence of all grade (OR, 4.79; 95% CI, 2.0–11.2; P = 0.0001) and high-grade (OR, 2.87; 95% CI, 1.0–7.6; P = 0.03) infection when compared with single-agent PI3K–AKT–mTOR inhibitors.Conclusions: Inhibitors of the PI3K–AKT–mTOR pathway can be associated with a higher risk of infection. Combinations of PI3K–AKT–mTOR inhibitors and cytotoxic chemotherapy significantly increase the risk of infection. This should be taken into consideration during the design and conduct of trials involving PI3K–AKT–mTOR pathway inhibitors, particularly when combined with chemotherapy or myelosuppressive agents. Clin Cancer Res; 21(8); 1869–76. ©2015 AACR.

PDF file, 1749K, Figure S4. Changes in tumor mitotic index on days 1, 7, and 21.

PDF file, 2119K, Figure S5. Changes in chromosome alignment and spindle bipolarity on days 1 and 21.

PDF file, 2001K, Figure S3. Changes in skin apoptotic index on days 7, 14 and 21.

XLS file 41K, RPPA biomarkers

Purpose:Sensitive methods for risk stratification, monitoring therapeutic efficacy, and early relapse detection may have a major impact on treatment decisions and patient management for stage III colorectal cancer patients. Beyond assessing the predictive power of postoperative ctDNA detection, we explored the added benefits of serial analysis: assessing adjuvant chemotherapy (ACT) efficacy, early relapse detection, and ctDNA growth rates.Experimental Design:We recruited 168 patients with stage III colorectal cancer treated with curative intent at Danish and Spanish hospitals between 2014 and 2019. To quantify ctDNA in plasma samples (n = 1,204), 16 patient-specific somatic single-nucleotide variants were profiled using multiplex-PCR, next-generation sequencing.Results:Detection of ctDNA was a strong recurrence predictor postoperatively [HR = 7.0; 95% confidence interval (CI), 3.7–13.5; P < 0.001] and directly after ACT (HR = 50.76; 95% CI, 15.4–167; P < 0.001). The recurrence rate of postoperative ctDNA-positive patients treated with ACT was 80% (16/20). Only patients who cleared ctDNA permanently during ACT did not relapse. Serial ctDNA assessment after the end of treatment was similarly predictive of recurrence (HR = 50.80; 95% CI, 14.9–172; P < 0.001), and revealed two distinct rates of exponential ctDNA growth, slow (25% ctDNA-increase/month) and fast (143% ctDNA-increase/month; P < 0.001). The ctDNA growth rate was prognostic of survival (HR = 2.7; 95% CI, 1.1–6.7; P = 0.039). Serial ctDNA analysis every 3 months detected recurrence with a median lead-time of 9.8 months compared with standard-of-care computed tomography.Conclusions:Serial postoperative ctDNA analysis has a strong prognostic value and enables tumor growth rate assessment. The novel combination of ctDNA detection and growth rate assessment provides unique opportunities for guiding decision-making.See related commentary by Morris and George, p. 438

XLS file 38K, Single-biomarker tumor growth inhibition projection

Supplementary Figure 2. Combination therapy with ridaforolimus and dalotuzumab potentiates PI3K pathway inhibition and blocks cancer cell proliferation

Supplementary Figure 4. Responder biomarker hypothesis for ridaforolimus and dalotuzumab?based therapy

PDF file 117K, Supplementary Materials and Methods -Supplementary Figure Legends -Supplementary Table Legends

Purpose:Despite the clinical advantage of the combination of trastuzumab and platinum-based chemotherapy in HER2-amplified tumors, resistance will eventually develop. The identification of molecular mechanisms related to primary and acquired resistance is needed.Experimental Design:We generated lapatinib- and trastuzumab-resistant clones deriving from two different HER2-amplified gastric cancer cell lines. Molecular changes such as protein expression and gene-expression profile were evaluated to detect alterations that could be related to resistance. Functional studies in vitro were corroborated in vivo. The translational relevance of our findings was verified in a patient cohort.Results:We found RPS6 activation and NRF2 to be related to anti-HER2 drug resistance. RPS6 or NRF2 inhibition with siRNA reduced viability and resistance to anti-HER2 drugs. In knockdown cells for RPS6, a decrease of NRF2 expression was demonstrated, suggesting a potential link between these two proteins. The use of a PI3K/TORC1/TORC2 inhibitor, tested in vitro and in vivo, inhibited pRPS6 and NRF2 expression and caused cell and tumor growth reduction, in anti–HER2-resistant models. In a cohort of HER2-amplified patients treated with trastuzumab and chemotherapy, a high level of NRF2 at baseline corresponds with worse progression-free survival.Conclusions:NRF2 through the PI3K/AKT/mTOR/RPS6 pathway could be a potential effector of resistance to anti-HER2 drugs in our models. RPS6 inhibition decreases NRF2 expression and restores sensitivity in HER2-amplified gastric cancer in vitro and in vivo. High NRF2 expression in gastric cancer patients predicts resistance to treatment. RPS6 and NRF2 inhibition could prevent resistance to anti-HER2 drugs.

Detailed description of phase I and registration trials for each approved small molecule. Dose and schedule developed will be specified, along with dose modifications due to toxicity.

PDF file, 1635K, Figure S1. MLN8237 dose-escalation and schedule extension schema.

Purpose: Sensitive methods for risk stratification, monitoring therapeutic efficacy, and early relapse detection may have a major impact on treatment decisions and patient management for stage III colorectal cancer patients. Beyond assessing the predictive power of postoperative ctDNA detection, we explored the added benefits of serial analysis: assessing adjuvant chemotherapy (ACT) efficacy, early relapse detection, and ctDNA growth rates. Experimental Design: We recruited 168 patients with stage III colorectal cancer treated with curative intent at Danish and Spanish hospitals between 2014 and 2019. To quantify ctDNA in plasma samples (n = 1,204), 16 patient-specific somatic single-nucleotide variants were profiled using multiplex-PCR, next-generation sequencing. Results: Detection of ctDNA was a strong recurrence predictor postoperatively [HR = 7.0; 95% confidence interval (CI), 3.7–13.5; P < 0.001] and directly after ACT (HR = 50.76; 95% CI, 15.4–167; P < 0.001). The recurrence rate of postoperative ctDNA-positive patients treated with ACT was 80% (16/20). Only patients who cleared ctDNA permanently during ACT did not relapse. Serial ctDNA assessment after the end of treatment was similarly predictive of recurrence (HR = 50.80; 95% CI, 14.9–172; P < 0.001), and revealed two distinct rates of exponential ctDNA growth, slow (25% ctDNA-increase/month) and fast (143% ctDNA-increase/month; P < 0.001). The ctDNA growth rate was prognostic of survival (HR = 2.7; 95% CI, 1.1–6.7; P = 0.039). Serial ctDNA analysis every 3 months detected recurrence with a median lead-time of 9.8 months compared with standard-of-care computed tomography. Conclusions: Serial postoperative ctDNA analysis has a strong prognostic value and enables tumor growth rate assessment. The novel combination of ctDNA detection and growth rate assessment provides unique opportunities for guiding decision-making. See related commentary by Morris and George, p. 438

Precision medicine approaches for solid tumors are mainly based on genomics. Its employment in clinical trials has led to somewhat underwhelming results, except for single responses. Moreover, several factors can influence the response, such as gene and protein expression, the coexistence of different genomic alterations or post-transcriptional/translational modifications, the impact of tumor microenvironment, etc., therefore making it insufficient to employ a genomics-only approach to predict response. Recently, the implementation of patient-derived organoids has shed light on the possibility to use them to predict patient response to drug treatment. This could offer for the first time the possibility to move precision medicine to a functional environment.

Background CH5126766 (also known as VS-6766, and previously named R05126766), a novel MEK-pan-RAF inhibitor, has shown antitumour activity across various solid tumours; however, its initial development was limited by toxicity. We aimed to investigate the safety and toxicity profile of intermittent dosing schedules of CH5126766, and the antitumour activity of this drug in patients with solid tumours and multiple myeloma harbouring RAS-RAF-MEK pathway mutations. Methods We did a single-centre, open-label, phase 1 dose-escalation and basket dose-expansion study at the Royal Marsden National Health Service Foundation Trust (London, UK). Patients were eligible for the study if they were aged 18 years or older, had cancers that were refractory to conventional treatment or for which no conventional therapy existed, and if they had a WHO performance status score of 0 or 1. For the dose-escalation phase, eligible patients had histologically or cytologically confirmed advanced or inetastatic solid tumours. For the basket doseexpansion phase, eligible patients had advanced or metastatic solid tumours or multiple myeloma harbouring RAS-RAF-MEK pathway mutations. During the dose-escalation phase, we evaluated three intermittent oral schedules (28-day cycles) in patients with solid tumours: (1) 4.0 mg or 3.2 mg CH5126766 three times per week; (2) 4.0 mg CH5126766 twice per week; and (3) toxicity-guided dose interruption schedule, in which treatment at the recommended phase 2 dose (4.0 mg CH5126766 twice per week) was de-escalated to 3 weeks on followed by 1 week off if patients had prespecified toxic effects (grade 2 or worse diarrhoea, rash, or creatinine phosphokinase elevation). In the basket dose-expansion phase, we evaluated antitumour activity at the recommended phase 2 dose, determined from the dose-escalation phase, in biomarker-selected patients. The primary endpoints were the recommended phase 2 dose at which no more than one out of six patients had a treatment-related dose-limiting toxicity, and the safety and toxicity profile of each dosing schedule. The key secondary endpoint was investigator-assessed response rate in the dose-expansion phase. Patients who received at least one dose of the study drug were evaluable for safety and patients who received one cycle of the study drug and underwent baseline disease assessment were evaluable for response. This trial is registered with ClinicalTrials.gov, NCT02407509. Findings Between June 5,2013, and Jan 10,2019,58 eligible patients were enrolled to the study: 29 patients with solid tumours were included in the dose-escalation cohort and 29 patients with solid tumours or multiple myeloma were included in the basket dose-expansion cohort (12 non-small-cell lung cancer, five gynaecological malignancy, four colorectal cancer, one melanoma, and seven multiple myeloma). Median follow-up at the time of data cutoff was 2.3 months (IQR 1.6-3.5). Dose-limiting toxicities included grade 3 bilateral retinal pigment epithelial detachment in one patient who received 4.0 mg CH5126766 three times per week, and grade 3 rash (in two patients) and grade 3 creatinine phosphokinase elevation (in one patient) in those who received 3.2 mg CH5126766 three times per week. 4.0 mg CH5126766 twice per week (on Monday and Thursday or Tuesday and Friday) was established as the recommended phase 2 dose. The most common grade 3-4 treatment-related adverse events were rash (11 [19%] patients), creatinine phosphokinase elevation (six [11%1), hypoalbuminaemia (six [11%]), and fatigue (four [7%1). Five (9%) patients had serious treatment-related adverse events. There were no treatment-related deaths. Eight (14%) of 57 patients died during the trial due to disease progression. Seven (27% [95% CI 11.6-47.8]) of 26 response-evaluable patients in the basket expansion achieved objective responses. Interpretation To our knowledge, this is the first study to show that highly intermittent schedules of a RAF-MEK inhibitor has antitumour activity across various cancers with RAF-RAS-MEK pathway mutations, and that this inhibitor is tolerable. CH5126766 used as a monotherapy and in combination regimens warrants further evaluation. Copyright (C) 2020 Elsevier Ltd. All rights reserved.