Efficacy and safety of pembrolizumab in patients with advanced urothelial carcinoma deemed potentially ineligible for platinum-containing chemotherapy: Post hoc analysis of KEYNOTE-052 and LEAP-011.

BACKGROUND: First-line pembrolizumab monotherapy is a standard of care for platinum-ineligible patients with advanced urothelial carcinoma (UC). No global standardized definition of platinum ineligibility exists. This study aimed to evaluate the efficacy and safety of pembrolizumab monotherapy in patients with UC who met various criteria for platinum ineligibility. METHODS: Patients from KEYNOTE-052 and LEAP-011 deemed potentially platinum ineligible were pooled for this post hoc exploratory analysis as follows: group 1: Eastern Cooperative Oncology Group performance status (ECOG PS) 2; group 2: ECOG PS 2 and age ≥80 years, renal dysfunction, or visceral disease; and group 3: any two other factors regardless of ECOG PS. Patients received pembrolizumab 200 mg intravenously every 3 weeks. End points included objective response rate (ORR), progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors, version 1.1, by blinded independent central review, overall survival (OS), and safety. RESULTS: A total of 612 patients treated with pembrolizumab from KEYNOTE-052 (n = 370) and LEAP-011 (n = 242) were included; the median (range) follow-up was 56.3 months (51.2-65.3 months) and 12.8 months (0.2-25.1 months), respectively. For group 1, ORR was 26.2%, median PFS was 2.7 months, and median OS was 10.1 months. For group 2, ORR ranged from 23.5% to 33.3%, median PFS ranged from 2.1 to 4.4 months, and median OS ranged from 9.1 to 10.1 months. For group 3, ORR ranged from 25.7% to 27.9%, median PFS ranged from 2.1 to 2.8 months, and median OS ranged from 9.0 to 10.6 months. Treatment-related adverse event rates were consistent across groups. CONCLUSIONS: Frontline pembrolizumab has consistent antitumor activity and safety in patients with advanced UC categorized as potentially ineligible for platinum-based chemotherapy, regardless of the variable definitions of platinum ineligibility used.

Fruquintinib versus placebo in patients with refractory metastatic colorectal cancer (FRESCO-2): an international, multicentre, randomised, double-blind, phase 3 study.

BACKGROUND: There is a paucity of effective systemic therapy options for patients with advanced, chemotherapy-refractory colorectal cancer. We aimed to evaluate the efficacy and safety of fruquintinib, a highly selective and potent oral inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2, and 3, in patients with heavily pretreated metastatic colorectal cancer. METHODS: We conducted an international, randomised, double-blind, placebo-controlled, phase 3 study (FRESCO-2) at 124 hospitals and cancer centres across 14 countries. We included patients aged 18 years or older (≥20 years in Japan) with histologically or cytologically documented metastatic colorectal adenocarcinoma who had received all current standard approved cytotoxic and targeted therapies and progressed on or were intolerant to trifluridine-tipiracil or regorafenib, or both. Eligible patients were randomly assigned (2:1) to receive fruquintinib (5 mg capsule) or matched placebo orally once daily on days 1-21 in 28-day cycles, plus best supportive care. Stratification factors were previous trifluridine-tipiracil or regorafenib, or both, RAS mutation status, and duration of metastatic disease. Patients, investigators, study site personnel, and sponsors, except for selected sponsor pharmacovigilance personnel, were masked to study group assignments. The primary endpoint was overall survival, defined as the time from randomisation to death from any cause. A non-binding futility analysis was done when approximately one-third of the expected overall survival events had occurred. Final analysis occurred after 480 overall survival events. This study is registered with ClinicalTrials.gov, NCT04322539, and EudraCT, 2020-000158-88, and is ongoing but not recruiting. FINDINGS: Between Aug 12, 2020, and Dec 2, 2021, 934 patients were assessed for eligibility and 691 were enrolled and randomly assigned to receive fruquintinib (n=461) or placebo (n=230). Patients had received a median of 4 lines (IQR 3-6) of previous systemic therapy for metastatic disease, and 502 (73%) of 691 patients had received more than 3 lines. Median overall survival was 7·4 months (95% CI 6·7-8·2) in the fruquintinib group versus 4·8 months (4·0-5·8) in the placebo group (hazard ratio 0·66, 95% CI 0·55-0·80; p<0·0001). Grade 3 or worse adverse events occurred in 286 (63%) of 456 patients who received fruquintinib and 116 (50%) of 230 who received placebo; the most common grade 3 or worse adverse events in the fruquintinib group included hypertension (n=62 [14%]), asthenia (n=35 [8%]), and hand-foot syndrome (n=29 [6%]). There was one treatment-related death in each group (intestinal perforation in the fruquintinib group and cardiac arrest in the placebo group). INTERPRETATION: Fruquintinib treatment resulted in a significant and clinically meaningful benefit in overall survival compared with placebo in patients with refractory metastatic colorectal cancer. These data support the use of fruquintinib as a global treatment option for patients with refractory metastatic colorectal cancer. Ongoing analysis of the quality of life data will further establish the clinical benefit of fruquintinib in this patient population. FUNDING: HUTCHMED.

Efficacy and Safety of Half-Dose Gadopiclenol versus Full-Dose Gadobutrol for Contrast-enhanced Body MRI.

Background Gadopiclenol is a macrocyclic gadolinium-based contrast agent (GBCA) with higher relaxivity compared with standard GBCAs, potentially allowing gadolinium dose reduction without decreasing efficacy. Purpose To investigate whether gadopiclenol at 0.05 mmol/kg is noninferior to gadobutrol at 0.1 mmol/kg for lesion visualization in body MRI. Materials and Methods A randomized, double-blind, crossover, phase 3 study was conducted between August 2019 and December 2020 at 33 centers in 11 countries. Adults with at least one suspected focal lesion in one of three different body regions (head and neck; breast, thorax, abdomen, or pelvis; or musculoskeletal system) underwent two contrast-enhanced MRI examinations, randomized to start with either gadopiclenol or gadobutrol. MRI examinations were read by three blinded expert readers for each respective body region. Readers rated border delineation, internal morphologic characteristics, and visual contrast enhancement. Three additional blinded readers assessed reader preference. For safety analysis, adverse events were recorded. The differences between gadopiclenol- and gadobutrol-enhanced MRI in terms of lesion visualization were analyzed with a generalized linear mixed model using a two-sided paired t test. Results Among 273 participants (mean age, 57 years ± 13 [SD]; 162 women) who underwent both gadopiclenol- and gadobutrol-enhanced MRI and had at least one correlating lesion, 260 participants without major protocol deviations were analyzed for noninferiority. Gadopiclenol was noninferior to gadobutrol for all qualitative visualization parameters and for all readers (lower limit 95% CI of the difference of at least -0.10, which was above the noninferiority margin [-0.35]; P < .001). For most participants (75%-83% [206-228 of 276]), readers reported no preference between gadopiclenol- and gadobutrol-enhanced images. Adverse events did not differ in frequency, intensity, type, or association with GBCA injection (12 of 288 participants receiving gadopiclenol and 16 of 290 receiving gadobutrol). Conclusion Gadopiclenol at 0.05 mmol/kg was comparable with gadobutrol at 0.1 mmol/kg for lesion evaluation at contrast-enhanced body MRI and had a similar safety profile. Clinical trial registration no. NCT03986138 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Bashir and Thomas in this issue.

Adjuvant atezolizumab after adjuvant chemotherapy in resected stage IB-IIIA non-small-cell lung cancer (IMpower010): a randomised, multicentre, open-label, phase 3 trial.

BACKGROUND: Novel adjuvant strategies are needed to optimise outcomes after complete surgical resection in patients with early-stage non-small-cell lung cancer (NSCLC). We aimed to evaluate adjuvant atezolizumab versus best supportive care after adjuvant platinum-based chemotherapy in these patients. METHODS: IMpower010 was a randomised, multicentre, open-label, phase 3 study done at 227 sites in 22 countries and regions. Eligible patients were 18 years or older with completely resected stage IB (tumours ≥4 cm) to IIIA NSCLC per the Union Internationale Contre le Cancer and American Joint Committee on Cancer staging system (7th edition). Patients were randomly assigned (1:1) by a permuted-block method (block size of four) to receive adjuvant atezolizumab (1200 mg every 21 days; for 16 cycles or 1 year) or best supportive care (observation and regular scans for disease recurrence) after adjuvant platinum-based chemotherapy (one to four cycles). The primary endpoint, investigator-assessed disease-free survival, was tested hierarchically first in the stage II-IIIA population subgroup whose tumours expressed PD-L1 on 1% or more of tumour cells (SP263), then all patients in the stage II-IIIA population, and finally the intention-to-treat (ITT) population (stage IB-IIIA). Safety was evaluated in all patients who were randomly assigned and received atezolizumab or best supportive care. IMpower010 is registered with ClinicalTrials.gov, NCT02486718 (active, not recruiting). FINDINGS: Between Oct 7, 2015, and Sept 19, 2018, 1280 patients were enrolled after complete resection. 1269 received adjuvant chemotherapy, of whom 1005 patients were eligible for randomisation to atezolizumab (n=507) or best supportive care (n=498); 495 in each group received treatment. After a median follow-up of 32·2 months (IQR 27·4-38·3) in the stage II-IIIA population, atezolizumab treatment improved disease-free survival compared with best supportive care in patients in the stage II-IIIA population whose tumours expressed PD-L1 on 1% or more of tumour cells (HR 0·66; 95% CI 0·50-0·88; p=0·0039) and in all patients in the stage II-IIIA population (0·79; 0·64-0·96; p=0·020). In the ITT population, HR for disease-free survival was 0·81 (0·67-0·99; p=0·040). Atezolizumab-related grade 3 and 4 adverse events occurred in 53 (11%) of 495 patients and grade 5 events in four patients (1%). INTERPRETATION: IMpower010 showed a disease-free survival benefit with atezolizumab versus best supportive care after adjuvant chemotherapy in patients with resected stage II-IIIA NSCLC, with pronounced benefit in the subgroup whose tumours expressed PD-L1 on 1% or more of tumour cells, and no new safety signals. Atezolizumab after adjuvant chemotherapy offers a promising treatment option for patients with resected early-stage NSCLC. FUNDING: F Hoffmann-La Roche and Genentech.

Analysis by region of outcomes for patients with advanced renal cell carcinoma treated with cabozantinib or everolimus: a sub-analysis of the METEOR study.

INTRODUCTION: METEOR was a phase 3 trial (NCT01865747) of cabozantinib versus everolimus in adults with advanced or metastatic clear cell RCC previously treated with VEGF receptor (VEGFR) tyrosine kinase inhibitors (TKIs). This post hoc analysis of METEOR compared outcomes for patients recruited from European and non-European countries. MATERIAL AND METHODS: Adults with advanced/metastatic clear cell RCC who had received ≥ 1 prior VEGFR-TKI treatment were randomized 1:1 to receive cabozantinib or everolimus. Patients were categorized by recruitment region: Europe or outside of Europe (rest of world [RoW]). Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and adverse events (AEs) were compared between regional subgroups. RESULTS: In total, there were 320 eligible patients from Europe (cabozantinib, 167; everolimus, 153) and 338 from RoW (North America, 240 patients; Asia-Pacific, 86; Latin America, 12; randomized as cabozantinib, 163; everolimus, 175). PFS and OS were longer with cabozantinib than with everolimus and similar for the Europe and RoW subgroups. For PFS, the hazard ratio (HR) for cabozantinib versus everolimus was 0.54 for the Europe subgroup (p < .001) and 0.50 for the RoW subgroup (p < .001). For OS, the HR was 0.75 for the Europe subgroup (p = .034) and 0.69 for the RoW subgroup (p = .006). ORR in the Europe subgroup was 15% for cabozantinib and 3.9% for everolimus (p < .001). For the RoW subgroup, ORR was 20% for cabozantinib and 2.9% for everolimus (p < .001). Incidence of grade 3/4 AEs were similar for the Europe (cabozantinib, 74%; everolimus, 58%) and RoW subgroups (cabozantinib, 69%; everolimus, 64%). CONCLUSION: In the METEOR trial, efficacy outcomes for patients recruited from European and non-European countries favored cabozantinib over everolimus. The efficacy and safety results for the regional subgroups were consistent with those of the overall METEOR population.

Pembrolizumab alone or combined with chemotherapy versus chemotherapy as first-line therapy for advanced urothelial carcinoma (KEYNOTE-361): a randomised, open-label, phase 3 trial.

BACKGROUND: PD-1 and PD-L1 inhibitors are active in metastatic urothelial carcinoma, but positive randomised data supporting their use as a first-line treatment are lacking. In this study we assessed outcomes with first-line pembrolizumab alone or combined with chemotherapy versus chemotherapy for patients with previously untreated advanced urothelial carcinoma. METHODS: KEYNOTE-361 is a randomised, open-label, phase 3 trial of patients aged at least 18 years, with untreated, locally advanced, unresectable, or metastatic urothelial carcinoma, with an Eastern Cooperative Oncology Group performance status of up to 2. Eligible patients were enrolled from 201 medical centres in 21 countries and randomly allocated (1:1:1) via an interactive voice-web response system to intravenous pembrolizumab 200 mg every 3 weeks for a maximum of 35 cycles plus intravenous chemotherapy (gemcitabine [1000 mg/m2] on days 1 and 8 and investigator's choice of cisplatin [70 mg/m2] or carboplatin [area under the curve 5] on day 1 of every 3-week cycle) for a maximum of six cycles, pembrolizumab alone, or chemotherapy alone, stratified by choice of platinum therapy and PD-L1 combined positive score (CPS). Neither patients nor investigators were masked to the treatment assignment or CPS. At protocol-specified final analysis, sequential hypothesis testing began with superiority of pembrolizumab plus chemotherapy versus chemotherapy alone in the total population (all patients randomly allocated to a treatment) for the dual primary endpoints of progression-free survival (p value boundary 0·0019), assessed by masked, independent central review, and overall survival (p value boundary 0·0142), followed by non-inferiority and superiority of overall survival for pembrolizumab versus chemotherapy in the patient population with CPS of at least 10 and in the total population (also a primary endpoint). Safety was assessed in the as-treated population (all patients who received at least one dose of study treatment). This study is completed and is no longer enrolling patients, and is registered at ClinicalTrials.gov, number NCT02853305. FINDINGS: Between Oct 19, 2016 and June 29, 2018, 1010 patients were enrolled and allocated to receive pembrolizumab plus chemotherapy (n=351), pembrolizumab monotherapy (n=307), or chemotherapy alone (n=352). Median follow-up was 31·7 months (IQR 27·7-36·0). Pembrolizumab plus chemotherapy versus chemotherapy did not significantly improve progression-free survival, with a median progression-free survival of 8·3 months (95% CI 7·5-8·5) in the pembrolizumab plus chemotherapy group versus 7·1 months (6·4-7·9) in the chemotherapy group (hazard ratio [HR] 0·78, 95% CI 0·65-0·93; p=0·0033), or overall survival, with a median overall survival of 17·0 months (14·5-19·5) in the pembrolizumab plus chemotherapy group versus 14·3 months (12·3-16·7) in the chemotherapy group (0·86, 0·72-1·02; p=0·0407). No further formal statistical hypothesis testing was done. In analyses of overall survival with pembrolizumab versus chemotherapy (now exploratory based on hierarchical statistical testing), overall survival was similar between these treatment groups, both in the total population (15·6 months [95% CI 12·1-17·9] with pembrolizumab vs 14·3 months [12·3-16·7] with chemotherapy; HR 0·92, 95% CI 0·77-1·11) and the population with CPS of at least 10 (16·1 months [13·6-19·9] with pembrolizumab vs 15·2 months [11·6-23·3] with chemotherapy; 1·01, 0·77-1·32). The most common grade 3 or 4 adverse event attributed to study treatment was anaemia with pembrolizumab plus chemotherapy (104 [30%] of 349 patients) or chemotherapy alone (112 [33%] of 342 patients), and diarrhoea, fatigue, and hyponatraemia (each affecting four [1%] of 302 patients) with pembrolizumab alone. Six (1%) of 1010 patients died due to an adverse event attributed to study treatment; two patients in each treatment group. One each occurred due to cardiac arrest and device-related sepsis in the pembrolizumab plus chemotherapy group, one each due to cardiac failure and malignant neoplasm progression in the pembrolizumab group, and one each due to myocardial infarction and ischaemic colitis in the chemotherapy group. INTERPRETATION: The addition of pembrolizumab to first-line platinum-based chemotherapy did not significantly improve efficacy and should not be widely adopted for treatment of advanced urothelial carcinoma. FUNDING: Merck Sharp and Dohme, a subsidiary of Merck, Kenilworth, NJ, USA.

Exploratory composite endpoint demonstrates benefit of trilaciclib across multiple clinically meaningful components of myeloprotection in patients with small cell lung cancer.

Chemotherapy-induced myelosuppression is an acute, dose-limiting toxicity of chemotherapy regimens used in the treatment of extensive-stage small cell lung cancer (ES-SCLC). Trilaciclib protects haematopoietic stem and progenitor cells from chemotherapy-induced damage (myeloprotection). To assess the totality of the myeloprotective benefits of trilaciclib, including analysis of several clinically relevant but low-frequency events, an exploratory composite endpoint comprising five major adverse haematological events (MAHE) was prospectively defined: all-cause hospitalisations, all-cause chemotherapy dose reductions, febrile neutropenia (FN), prolonged severe neutropenia (SN) and red blood cell (RBC) transfusions on/after Week 5. MAHE and its individual components were assessed in three randomised, double-blind, placebo-controlled Phase 2 trials in patients receiving a platinum/etoposide or topotecan-containing chemotherapy regimen for ES-SCLC and in data pooled from the three trials. A total of 242 patients were randomised across the three trials (trilaciclib, n = 123; placebo, n = 119). In the individual trials and the pooled analysis, administering trilaciclib prior to chemotherapy resulted in a statistically significant reduction in the cumulative incidence of MAHE compared to placebo. In the pooled analysis, the cumulative incidences of all-cause chemotherapy dose reductions, FN, prolonged SN and RBC transfusions on/after Week 5 were significantly reduced with trilaciclib vs placebo; however, no significant difference was observed in rates of all-cause hospitalisations. Additionally, compared to placebo, trilaciclib significantly extended the amount of time patients remained free of MAHE. These data support the myeloprotective benefits of trilaciclib and its ability to improve the overall safety profile of myelosuppressive chemotherapy regimens used to treat patients with ES-SCLC.

Pembrolizumab plus Chemotherapy for Squamous Non-Small-Cell Lung Cancer.

BACKGROUND: Standard first-line therapy for metastatic, squamous non-small-cell lung cancer (NSCLC) is platinum-based chemotherapy or pembrolizumab (for patients with programmed death ligand 1 [PD-L1] expression on ≥50% of tumor cells). More recently, pembrolizumab plus chemotherapy was shown to significantly prolong overall survival among patients with nonsquamous NSCLC. METHODS: In this double-blind, phase 3 trial, we randomly assigned, in a 1:1 ratio, 559 patients with untreated metastatic, squamous NSCLC to receive 200 mg of pembrolizumab or saline placebo for up to 35 cycles; all the patients also received carboplatin and either paclitaxel or nanoparticle albumin-bound [nab]-paclitaxel for the first 4 cycles. Primary end points were overall survival and progression-free survival. RESULTS: After a median follow-up of 7.8 months, the median overall survival was 15.9 months (95% confidence interval [CI], 13.2 to not reached) in the pembrolizumab-combination group and 11.3 months (95% CI, 9.5 to 14.8) in the placebo-combination group (hazard ratio for death, 0.64; 95% CI, 0.49 to 0.85; P<0.001). The overall survival benefit was consistent regardless of the level of PD-L1 expression. The median progression-free survival was 6.4 months (95% CI, 6.2 to 8.3) in the pembrolizumab-combination group and 4.8 months (95% CI, 4.3 to 5.7) in the placebo-combination group (hazard ratio for disease progression or death, 0.56; 95% CI, 0.45 to 0.70; P<0.001). Adverse events of grade 3 or higher occurred in 69.8% of the patients in the pembrolizumab-combination group and in 68.2% of the patients in the placebo-combination group. Discontinuation of treatment because of adverse events was more frequent in the pembrolizumab-combination group than in the placebo-combination group (13.3% vs. 6.4%). CONCLUSIONS: In patients with previously untreated metastatic, squamous NSCLC, the addition of pembrolizumab to chemotherapy with carboplatin plus paclitaxel or nab-paclitaxel resulted in significantly longer overall survival and progression-free survival than chemotherapy alone. (Funded by Merck Sharp & Dohme; KEYNOTE-407 ClinicalTrials.gov number, NCT02775435 .).

Pembrolizumab versus Chemotherapy for PD-L1-Positive Non-Small-Cell Lung Cancer.

BACKGROUND: Pembrolizumab is a humanized monoclonal antibody against programmed death 1 (PD-1) that has antitumor activity in advanced non-small-cell lung cancer (NSCLC), with increased activity in tumors that express programmed death ligand 1 (PD-L1). METHODS: In this open-label, phase 3 trial, we randomly assigned 305 patients who had previously untreated advanced NSCLC with PD-L1 expression on at least 50% of tumor cells and no sensitizing mutation of the epidermal growth factor receptor gene or translocation of the anaplastic lymphoma kinase gene to receive either pembrolizumab (at a fixed dose of 200 mg every 3 weeks) or the investigator's choice of platinum-based chemotherapy. Crossover from the chemotherapy group to the pembrolizumab group was permitted in the event of disease progression. The primary end point, progression-free survival, was assessed by means of blinded, independent, central radiologic review. Secondary end points were overall survival, objective response rate, and safety. RESULTS: Median progression-free survival was 10.3 months (95% confidence interval [CI], 6.7 to not reached) in the pembrolizumab group versus 6.0 months (95% CI, 4.2 to 6.2) in the chemotherapy group (hazard ratio for disease progression or death, 0.50; 95% CI, 0.37 to 0.68; P<0.001). The estimated rate of overall survival at 6 months was 80.2% in the pembrolizumab group versus 72.4% in the chemotherapy group (hazard ratio for death, 0.60; 95% CI, 0.41 to 0.89; P=0.005). The response rate was higher in the pembrolizumab group than in the chemotherapy group (44.8% vs. 27.8%), the median duration of response was longer (not reached [range, 1.9+ to 14.5+ months] vs. 6.3 months [range, 2.1+ to 12.6+]), and treatment-related adverse events of any grade were less frequent (occurring in 73.4% vs. 90.0% of patients), as were grade 3, 4, or 5 treatment-related adverse events (26.6% vs. 53.3%). CONCLUSIONS: In patients with advanced NSCLC and PD-L1 expression on at least 50% of tumor cells, pembrolizumab was associated with significantly longer progression-free and overall survival and with fewer adverse events than was platinum-based chemotherapy. (Funded by Merck; KEYNOTE-024 ClinicalTrials.gov number, NCT02142738 .).

Buparlisib plus fulvestrant in postmenopausal women with hormone-receptor-positive, HER2-negative, advanced breast cancer progressing on or after mTOR inhibition (BELLE-3): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Activation of the PI3K/AKT/mTOR pathway occurs frequently in breast cancer that is resistant to endocrine therapy. Approved mTOR inhibitors effectively inhibit cell growth and proliferation but elicit AKT phosphorylation via a feedback activation pathway, potentially leading to resistance to mTOR inhibitors. We evaluated the efficacy and safety of buparlisib plus fulvestrant in patients with advanced breast cancer who were pretreated with endocrine therapy and mTOR inhibitors. METHODS: BELLE-3 was a randomised, double-blind, placebo-controlled, multicentre, phase 3 study. Postmenopausal women aged 18 years or older with histologically or cytologically confirmed hormone-receptor-positive, HER2-negative, locally advanced or metastatic breast cancer, who had relapsed on or after endocrine therapy and mTOR inhibitors, were recruited from 200 trial centres in 22 countries. Eligible patients were randomly assigned (2:1) via interactive response technology (block size of six) to receive oral buparlisib (100 mg per day) or matching placebo starting on day 1 of cycle 1, plus intramuscular fulvestrant (500 mg) on days 1 and 15 of cycle 1 and on day 1 of subsequent 28-day cycles. Randomisation was stratified by visceral disease status. The primary endpoint was progression-free survival by local investigator assessment as per the Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 in the full analysis population (all randomised patients, by intention-to-treat). Safety was analysed in all patients who received at least one dose of treatment and at least one post-baseline safety assessment. This study is registered with ClinicalTrials.gov, number NCT01633060, and is ongoing but no longer enrolling patients. FINDINGS: Between Jan 15, 2013, and March 31, 2016, 432 patients were randomly assigned to the buparlisib (n=289) or placebo (n=143) groups. Median progression-free survival was significantly longer in the buparlisib versus placebo group (3·9 months [95% CI 2·8-4·2] vs 1·8 months [1·5-2·8]; hazard ratio [HR] 0·67, 95% CI 0·53-0·84, one-sided p=0·00030). The most frequent grade 3-4 adverse events in the buparlisib versus placebo group were elevated alanine aminotransferase (63 [22%] of 288 patients vs four [3%] of 140), elevated aspartate aminotransferase (51 [18%] vs four [3%]), hyperglycaemia (35 [12%] vs none), hypertension (16 [6%] vs six [4%]), and fatigue (ten [3%] vs two [1%]). Serious adverse events were reported in 64 (22%) of 288 patients in the buparlisib group versus 23 (16%) of 140 in the placebo group; the most frequent serious adverse events (affecting ≥2% of patients) were elevated aspartate aminotransferase (six [2%] vs none), dyspnoea (six [2%] vs one [1%]), and pleural effusion (six [2%] vs none). On-treatment deaths occurred in ten (3%) of 288 patients in the buparlisib group and in six (4%) of 140 in the placebo group; most deaths were due to metastatic breast cancer, and two were considered treatment-related (cardiac failure [n=1] in the buparlisib group and unknown reason [n=1] in the placebo group). INTERPRETATION: The safety profile of buparlisib plus fulvestrant does not support its further development in this setting. Nonetheless, the efficacy of buparlisib supports the rationale for the use of PI3K inhibitors plus endocrine therapy in patients with PIK3CA mutations. FUNDING: Novartis Pharmaceuticals Corporation.

Health-related quality-of-life results for pembrolizumab versus chemotherapy in advanced, PD-L1-positive NSCLC (KEYNOTE-024): a multicentre, international, randomised, open-label phase 3 trial.

BACKGROUND: In the phase 3 KEYNOTE-024 trial, treatment with pembrolizumab conferred longer progression-free survival than did platinum-based therapy in patients with treatment-naive, advanced non-small-cell lung cancer (NSCLC) with a programmed cell death-ligand 1 (PD-L1) tumour proportion score of 50% or greater (PD-L1-positive). Here we report the prespecified exploratory endpoint of pembrolizumab versus chemotherapy on patient-reported outcomes (PROs). METHODS: In this multicentre, international, randomised, open-label, phase 3 trial, we recruited patients with treatment-naive, stage IV NSCLC in 102 sites in 16 countries. Eligible patients had measurable disease (per RECIST version 1.1) and an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. Patients were randomly assigned (1:1) via an interactive voice response system and integrated web response system to receive either pembrolizumab 200 mg every 3 weeks (35 cycles) or investigator-choice platinum-doublet chemotherapy (4-6 cycles or until documented disease progression or unacceptable toxicity). Randomisation was stratified according to geography, ECOG performance status, and histology. PROs were assessed at day 1 of cycles 1-3, every 9 weeks thereafter, at the treatment discontinuation visit, and at the 30-day safety assessment visit using the European Organisation for the Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 items (QLQ-C30), the EORTC Quality of Life Questionnaire Lung Cancer 13 items (QLQ-LC13), and the European Quality of Life 5 Dimensions-3 Level (EQ-5D-3L) questionnaire. The key exploratory PRO endpoints (analysed for all patients who received at least one dose of study treatment and completed at least one PRO instrument at at least one timepoint) were baseline-to-week-15 change in the QLQ-C30 global health status (GHS)/quality-of-life (QOL) score and time to deterioration of the composite of cough, chest pain, and dyspnoea in the QLQ-LC13. This study is registered with ClinicalTrials.gov, number NCT02142738, and is ongoing but no longer enrolling patients. FINDINGS: Between Sept 19, 2014, and Oct 29, 2015, 305 patients were randomly assigned to pembrolizumab (n=154) or chemotherapy (n=151). Three patients in each group did not complete any PRO instruments at any timepoints, and so 299 patients were included in the full analysis set. Of these patients, one in each group did not complete any PRO instruments before week 15, and so were not included in analyses of change from baseline to week 15. PRO compliance was greater than 90% at baseline and approximately 80% at week 15 for both groups. Least-squares mean baseline-to-week-15 change in QLQ-C30 GHS/QOL score was 6·9 (95% CI 3·3 to 10·6) for pembrolizumab and -0·9 (-4·8 to 3·0) for chemotherapy, for a difference of 7·8 (2·9 to 12·8; two-sided nominal p=0·0020). Fewer pembrolizumab-treated patients had deterioration in the QLQ-LC13 composite endpoint than did chemotherapy-treated patients (46 [31%] of 151 patients vs 58 [39%] of 148 patients). Time to deterioration was longer with pembrolizumab than with chemotherapy (median not reached [95% CI 8·5 to not reached] vs 5·0 months [3·6 to not reached]; hazard ratio 0·66, 95% CI 0·44-0·97; two-sided nominal p=0·029). INTERPRETATION: Pembrolizumab improves or maintains health-related QOL compared with that for chemotherapy, and might represent a new first-line standard of care for PD-L1-expressing, advanced NSCLC. FUNDING: Merck & Co.

First-line encorafenib plus binimetinib and pembrolizumab for advanced BRAF V600-mutant melanoma: Safety lead-in results from the randomized phase III STARBOARD study.

BACKGROUND: BRAF inhibitors plus MEK inhibitors (BRAFi/MEKi) and immune checkpoint inhibitors (CPIs) are approved for BRAF V600-mutant advanced melanoma. Combinations of BRAFi/MEKi with CPIs may further improve outcomes and could offer additional treatment strategies. METHODS: STARBOARD (NCT04657991) is a phase III study with an initial safety lead-in (SLI) phase conducted to determine the recommended phase III dose (RP3D) for encorafenib in combination with binimetinib and pembrolizumab. Patients with untreated, unresectable locally advanced or metastatic BRAF V600E/K-mutant cutaneous melanoma received binimetinib 45 mg twice daily and pembrolizumab 200 mg every 3 weeks plus encorafenib 450 mg once daily (COMBO450 plus pembrolizumab) or 300 mg once daily (COMBO300 plus pembrolizumab). The primary endpoint was the incidence of dose-limiting toxicities (DLTs). Secondary endpoints included safety, objective response, time to response, and duration of response. Progression-free survival was assessed post hoc. RESULTS: In the SLI, the median follow-up duration was 19.4 months. Twenty patients received COMBO450 plus pembrolizumab and 17 received COMBO300 plus pembrolizumab. DLTs occurred in 1 of 17 DLT-evaluable patients in the COMBO450 plus pembrolizumab arm and in 2 of 17 DLT-evaluable patients in the COMBO300 plus pembrolizumab arm. No treatment-related deaths occurred in either treatment arm. The overall response rate was 65.0 % in the COMBO450 plus pembrolizumab arm and 47.1 % in the COMBO300 plus pembrolizumab arm. CONCLUSION: The STARBOARD SLI showed that safety across the cohorts was generally comparable to the known safety profile of each agent. The standard dose regimen of COMBO450 plus pembrolizumab was chosen as the RP3D.

A global phase II randomized trial comparing oral taxane ModraDoc006/r to intravenous docetaxel in metastatic castration resistant prostate cancer.

STUDY AIM: ModraDoc006, an oral formulation of docetaxel, is co-administered with the cytochrome P450-3A4 and P-glycoprotein inhibitor, ritonavir (r): ModraDoc006/r. The preliminary efficacy and safety of oral ModraDoc006/r was evaluated in a global randomized phase II trial and compared to the current standard chemotherapy regimen of intravenous (i.v.) docetaxel and prednisone. METHODS: 103 mCRPC patients, chemotherapy-naïve with/without abiraterone and/or enzalutamide pretreated, with adequate organ function and evaluable disease per RECIST v1.1 and PCWG3 guidelines were randomized 1:1 into two cohorts. In Cohort 1, 49 patients received docetaxel 75 mg/m2 i.v. every 3 weeks (Q3W). In Cohort 2, 52 patients received ModraDoc006/r; 21 patients with a starting dose of ModraDoc006 30 mg with ritonavir 200 mg in the morning and ModraDoc006 20 mg with ritonavir 100 mg in the evening (30-20/200-100 mg) bi-daily-once-weekly (BIDW) on Days 1, 8, and 15 of a 21-day cycle. To alleviate tolerability, the starting dose was amended to ModraDoc006/r 20-20/200-100 mg in another 31 patients. All patients received prednisone 10 mg daily. Primary endpoint was rPFS. RESULTS: There was no significant difference in rPFS between the 2 arms (p = 0.1465). Median rPFS was 9.5 months and 11.1 months (95% CI) for ModraDoc006/r and i.v. docetaxel, respectively. Partial response was noted in 44.1% and 38.7% measurable disease patients, and 50% decline of PSA was seen in 23 (50%) and 26 (56.5%) evaluable cases treated with ModraDoc006/r and i.v. docetaxel, respectively. The safety profile of ModraDoc006/r 20-20/200-100 mg dose was significantly better than i.v. docetaxel, with mild (mostly Grade 1) gastrointestinal toxicities, no hematologic adverse events, and neuropathy and alopecia incidence of 11.5% and 25%, respectively. CONCLUSIONS: ModraDoc006/r potentially represents a widely applicable, convenient, effective, and better tolerated oral taxane therapy option for mCRPC. Further investigation of ModraDoc006/r in a large randomized trial is warranted.

Pembrolizumab With or Without Lenvatinib for First-Line Metastatic NSCLC With Programmed Cell Death-Ligand 1 Tumor Proportion Score of at least 1% (LEAP-007): A Randomized, Double-Blind, Phase 3 Trial.

INTRODUCTION: Lenvatinib plus pembrolizumab was found to have antitumor activity and acceptable safety in previously treated metastatic NSCLC. We evaluated first-line lenvatinib plus pembrolizumab versus placebo plus pembrolizumab in metastatic NSCLC in the LEAP-007 study (NCT03829332/NCT04676412). METHODS: Patients with previously untreated stage IV NSCLC with programmed cell death-ligand 1 tumor proportion score of at least 1% without targetable EGFR/ROS1/ALK aberrations were randomized 1:1 to lenvatinib 20 mg or placebo once daily; all patients received pembrolizumab 200 mg every 3 weeks for up to 35 cycles. Primary end points were progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors version 1.1 and overall survival (OS). We report results from a prespecified nonbinding futility analysis of OS performed at the fourth independent data and safety monitoring committee review (futility bound: one-sided p < 0.4960). RESULTS: A total of 623 patients were randomized. At median follow-up of 15.9 months, median (95% confidence interval [CI]) OS was 14.1 (11.4‒19.0) months in the lenvatinib plus pembrolizumab group versus 16.4 (12.6‒20.6) months in the placebo plus pembrolizumab group (hazard ratio = 1.10 [95% CI: 0.87‒1.39], p = 0.79744 [futility criterion met]). Median (95% CI) PFS was 6.6 (6.1‒8.2) months versus 4.2 (4.1‒6.2) months, respectively (hazard ratio = 0.78 [95% CI: 0.64‒0.95]). Grade 3 to 5 treatment-related adverse events occurred in 57.9% of patients (179 of 309) versus 24.4% (76 of 312). Per data and safety monitoring committee recommendation, the study was unblinded and lenvatinib and placebo were discontinued. CONCLUSIONS: Lenvatinib plus pembrolizumab did not have a favorable benefit‒risk profile versus placebo plus pembrolizumab. Pembrolizumab monotherapy remains an approved treatment option in many regions for first-line metastatic NSCLC with programmed cell death-ligand 1 tumor proportion score of at least 1% without EGFR/ALK alterations.

Pembrolizumab with or Without Lenvatinib as First-line Therapy for Patients with Advanced Urothelial Carcinoma (LEAP-011): A Phase 3, Randomized, Double-Blind Trial.

BACKGROUND: Pembrolizumab plus lenvatinib has shown antitumor activity and acceptable safety in patients with platinum-refractory urothelial carcinoma (UC). OBJECTIVE: To evaluate pembrolizumab plus either lenvatinib or placebo as first-line therapy for advanced UC in the phase 3 LEAP-011 study. DESIGN, SETTING, AND PARTICIPANTS: Patients with advanced UC who were ineligible for cisplatin-based therapy or any platinum-based chemotherapy were enrolled. INTERVENTION: Patients were randomly assigned (1:1) to pembrolizumab 200 mg intravenously every 3 wk plus either lenvatinib 20 mg or placebo orally once daily. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Dual primary endpoints were progression-free survival (PFS) and overall survival (OS). An external data monitoring committee (DMC) regularly reviewed safety and efficacy data every 3 mo. RESULTS AND LIMITATIONS: Between June 25, 2019 and July 21, 2021, 487 patients were allocated to receive lenvatinib plus pembrolizumab (n = 245) or placebo plus pembrolizumab (n = 242). The median time from randomization to the data cutoff date (July 26, 2021) was 12.8 mo (interquartile range, 6.9-19.3). The median PFS was 4.5 mo in the combination arm and 4.0 mo in the pembrolizumab arm (hazard ratio [HR] 0.90 [95% confidence interval {CI} 0.72-1.14]). The median OS was 11.8 mo for the combination arm and 12.9 mo for the pembrolizumab arm (HR 1.14 [95% CI 0.87-1.48]). Grade 3-5 adverse events attributed to trial treatment occurred in 123 of 241 patients (51%) treated with lenvatinib plus pembrolizumab and in 66 of 242 patients (27%) treated with placebo plus pembrolizumab. This trial was terminated earlier than initially planned based on recommendation from the DMC. CONCLUSIONS: The benefit-to-risk ratio for first-line lenvatinib plus pembrolizumab was not considered favorable versus pembrolizumab plus placebo as first-line therapy in patients with advanced UC. PATIENT SUMMARY: Lenvatinib plus pembrolizumab was not more effective than pembrolizumab plus placebo in patients with advanced urothelial carcinoma.

Blood tumor mutational burden and response to pembrolizumab plus chemotherapy in non-small cell lung cancer: KEYNOTE-782.

BACKGROUND: First-line pembrolizumab plus chemotherapy has shown clinical benefit in patients with metastatic non-small cell lung cancer (NSCLC) regardless of tissue tumor mutational burden (tTMB) status. Blood tumor mutational burden (bTMB), assessed using plasma-derived circulating tumor DNA (ctDNA), may be a surrogate for tTMB. The KEYNOTE-782 study evaluated the correlation of bTMB with the efficacy of first-line pembrolizumab plus chemotherapy in NSCLC. METHODS: Previously untreated patients with stage IV nonsquamous NSCLC received pembrolizumab 200 mg plus pemetrexed 500 mg/m2 and investigator's choice of carboplatin area under the curve 5 mg/mL/min or cisplatin 75 mg/m2 for 4 cycles, then pembrolizumab plus pemetrexed for ≤31 additional cycles every 3 weeks. Study objectives were to evaluate the association of baseline bTMB with objective response rate (ORR) (RECIST v1.1 by investigator assessment; primary), progression-free survival (PFS; RECIST v1.1 by investigator assessment), overall survival (OS), and adverse events (AEs; all secondary). A next-generation sequencing assay (GRAIL LLC) with a ctDNA panel that included lung cancer-associated and immune gene targets was used to measure bTMB. RESULTS: 117 patients were enrolled; median time from first dose to data cutoff was 19.3 months (range, 1.0-35.5). ORR was 40.2 % (95 % CI 31.2-49.6 %), median PFS was 7.2 months (95 % CI 5.6-9.8) and median OS was 18.1 months (95 % CI 13.5-25.6). Treatment-related AEs occurred in 113 patients (96.6 %; grade 3-5, n = 56 [47.9 %]). Of patients with evaluable bTMB (n = 101), the area under the receiver operating characteristics curve for continuous bTMB to discriminate response was 0.47 (95 % CI 0.36-0.59). Baseline bTMB was not associated with PFS or OS (posterior probabilities of positive association: 16.8 % and 7.8 %, respectively). CONCLUSIONS: AEs were consistent with the established safety profile of first-line pembrolizumab plus chemotherapy in NSCLC. Baseline bTMB did not show evidence of an association with efficacy.

Trifluridine-tipiracil plus bevacizumab versus capecitabine plus bevacizumab as first-line treatment for patients with metastatic colorectal cancer ineligible for intensive therapy (SOLSTICE): a randomised, open-label phase 3 study.

BACKGROUND: Trifluridine-tipiracil plus bevacizumab has shown efficacy in previous phase 2 studies including patients with unresectable metastatic colorectal cancer. We aimed to investigate first-line trifluridine-tipiracil plus bevacizumab versus capecitabine plus bevacizumab in patients with unresectable metastatic colorectal cancer ineligible for intensive treatment. METHODS: In this open-label, randomised, phase 3 study, we enrolled patients aged 18 years and older with histologically confirmed metastatic colorectal cancer, ineligible for full-dose doublet or triplet chemotherapy and curative resection across 25 countries and regions. Participants were randomly allocated (1:1) to trifluridine-tipiracil plus bevacizumab or capecitabine plus bevacizumab until disease progression or unacceptable toxicity using an interactive web response system, stratified by Eastern Cooperative Oncology Group (ECOG) performance status (0 vs 1 vs 2), primary tumour location (right vs left colon), and the main reason for not being a candidate for intensive therapy (clinical condition vs non-clinical condition). The primary endpoint was investigator-assessed progression-free survival, defined as the time from randomisation to radiological progression or death from any cause, in the intention-to-treat population. Safety was assessed in all patients having taken at least one dose of the study drug. The trial is ongoing, findings presented here are those of the primary analysis of progression-free survival, conducted after 629 events had occurred. This study is registered with ClinicalTrials.gov, NCT03869892. FINDINGS: Between March 21, 2019, and Sept 14, 2020, 856 patients (54% male, 46% female) were randomly assigned to trifluridine-tipiracil plus bevacizumab (n=426) or capecitabine plus bevacizumab (n=430). After a median follow-up of 16·6 months (95% CI 16·5-17·1), the hazard ratio for progression-free survival for trifluridine-tipiracil plus bevacizumab versus capecitabine plus bevacizumab was 0·87 (0·75-1·02; p=0·0464; protocol-defined significance level of p=0·021 not met). Investigator-assessed median progression-free survival was 9·4 months (95% CI 9·1-10·9) with trifluridine-tipiracil plus bevacizumab versus 9·3 months (8·9-9·8) with capecitabine plus bevacizumab. The most common grade 3 and higher treatment-emergent adverse events were neutropenia (220 [52%] of 423 patients in the trifluridine-tipiracil plus bevacizumab group vs six [1%] of 427 in the capecitabine plus bevacizumab group), decreased neutrophil count (78 [18%] vs four [<1%]), anaemia (60 [14%] vs 16 [4%]), and hand-foot syndrome (none vs 61 [15%]). Nine deaths (five in the trifluridine-tipiracil plus bevacizumab group and four in the capecitabine plus bevacizumab group) were treatment related. INTERPRETATION: First-line trifluridine-tipiracil plus bevacizumab was not superior to capecitabine plus bevacizumab in this population. As expected, the safety profile differed between the two treatments, but there were no new safety concerns. Trifluridine-tipiracil plus bevacizumab represents a feasible alternative to capecitabine plus bevacizumab in this population. FUNDING: Servier International Research Institute, Suresnes, France.

Baseline Mutations and ctDNA Dynamics as Prognostic and Predictive Factors in ER-Positive/HER2-Negative Metastatic Breast Cancer Patients.

PURPOSE: Prognostic and predictive biomarkers to cyclin-dependent kinases 4 and 6 inhibitors are lacking. Circulating tumor DNA (ctDNA) can be used to profile these patients and dynamic changes in ctDNA could be an early predictor of treatment efficacy. Here, we conducted plasma ctDNA profiling in patients from the PEARL trial comparing palbociclib+fulvestrant versus capecitabine to investigate associations between baseline genomic landscape and on-treatment ctDNA dynamics with treatment efficacy. EXPERIMENTAL DESIGN: Correlative blood samples were collected at baseline [cycle 1-day 1 (C1D1)] and prior to treatment [cycle 1-day 15 (C1D15)]. Plasma ctDNA was sequenced with a custom error-corrected capture panel, with both univariate and multivariate Cox models used for treatment efficacy associations. A prespecified methodology measuring ctDNA changes in clonal mutations between C1D1 and C1D15 was used for the on-treatment ctDNA dynamic model. RESULTS: 201 patients were profiled at baseline, with ctDNA detection associated with worse progression-free survival (PFS)/overall survival (OS). Detectable TP53 mutation showed worse PFS and OS in both treatment arms, even after restricting population to baseline ctDNA detection. ESR1 mutations were associated with worse OS overall, which was lost when restricting population to baseline ctDNA detection. PIK3CA mutations confer worse OS only to patients on the palbociclib+fulvestrant treatment arm. ctDNA dynamics analysis (n = 120) showed higher ctDNA suppression in the capecitabine arm. Patients without ctDNA suppression showed worse PFS in both treatment arms. CONCLUSIONS: We show impaired survival irrespective of endocrine or chemotherapy-based treatments for patients with hormone receptor-positive/HER2-negative metastatic breast cancer harboring plasma TP53 mutations. Early ctDNA suppression may provide treatment efficacy predictions. Further validation to fully demonstrate clinical utility of ctDNA dynamics is warranted.

Patient-Reported Health-Related Quality of Life in KEYNOTE-604: Pembrolizumab or Placebo Added to Etoposide and Platinum as First-Line Therapy for Extensive-Stage SCLC.

Introduction: In the phase 3 KEYNOTE-604 study (NCT03066778), pembrolizumab plus etoposide and platinum chemotherapy (EP) significantly (p = 0.0023) improved progression-free survival versus placebo plus EP in previously untreated extensive-stage SCLC (ES-SCLC). We present health-related quality of life (HRQoL) results from KEYNOTE-604. Methods: Patients with stage IV SCLC were randomized 1:1 to pembrolizumab 200 mg or placebo every 3 weeks for 35 cycles plus four cycles of EP. Secondary end points included mean change from baseline to week 18 in the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire-Core 30 (QLQ-C30) global health status/quality of life (GHS/QoL) scale and time to deterioration in the composite outcome of cough, chest pain, or dyspnea from QLQ-C30 and QLQ-Lung Cancer Module 13. Two-sided, nominal p values are reported. Results: A total of 439 patients completed at least one QLQ-C30 and QLQ-Lung Cancer Module 13 assessment (pembrolizumab + EP, n = 221; placebo + EP, n = 218). GHS/QoL scores improved from baseline to week 18: least squares mean (95% confidence interval [CI]) changes were 8.7 (5.3-12.1) for pembrolizumab plus EP and 4.2 (0.9-7.5) for placebo plus EP. Between-group differences in least squares mean scores were improved for pembrolizumab plus EP (4.4 [95% CI: 0.2-8.7], p = 0.040]). Median time to deterioration for the composite end point was not reached and 8.7 (95% CI: 5.9-not reached) months, respectively (hazard ratio = 0.80 [95% CI: 0.56-1.14], p = 0.208). Conclusions: First-line pembrolizumab plus EP therapy maintained HRQoL in patients with ES-SCLC and may be associated with greater improvement than placebo plus EP. Together with the efficacy and safety findings in KEYNOTE-604, HRQoL data support the benefit of pembrolizumab in ES-SCLC.

Overall survival with palbociclib plus endocrine therapy versus capecitabine in postmenopausal patients with hormone receptor-positive, HER2-negative metastatic breast cancer in the PEARL study.

BACKGROUND: An earlier analysis of the PEARL phase III study showed that palbociclib plus endocrine therapy (ET) does not improve progression-free survival (PFS) over capecitabine in aromatase inhibitor-resistant, hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer (MBC) patients. Here, we report the final overall survival (OS) analysis. METHODS: Postmenopausal patients (N = 601) were randomized 1:1 to capecitabine or palbociclib plus ET (exemestane, Cohort 1; fulvestrant, Cohort 2). OS was analysed in Cohort 2, the wild-type ESR1 population and the overall population. Additionally, we analysed subsequent systemic therapies and explored PFS2 (time from randomization to the end of the first subsequent therapy/death). RESULTS: OS was 31.1 months for palbociclib plus fulvestrant and 32.8 months for capecitabine (adjusted hazard ratio [aHR] 1.10, 95% confidence interval [CI] 0.81-1.50, P = 0.550). In the wild-type ESR1 population, OS was 37.2 months for palbociclib plus ET and 34.8 months for capecitabine (aHR 1.06, 95% CI 0.81-1.37, P = 0.683). In OS analyses, no subgroup showed superiority for palbociclib plus ET over capecitabine. OS in the overall population was 32.6 months for palbociclib plus ET and 30.9 months for capecitabine (P = 0.995). Subsequent systemic therapy was given to 79.8% and 82.9% of patients with palbociclib plus ET and capecitabine, respectively. Median PFS2 was similar between study arms (Cohort 2, P = 0.941; wild-type ESR1 population, P = 0.827). No new safety findings were observed. CONCLUSIONS: Palbociclib plus ET did not show a statistically superior OS compared to capecitabine in MBC patients progressing on aromatase inhibitors. TRIAL REGISTRATION: NCT02028507 (ClinTrials.gov), 2013-003170-27 (EudraCT).