Efficacy and safety of tepotinib in Asian patients with advanced NSCLC with MET exon 14 skipping enrolled in VISION.

BACKGROUND: Tepotinib, a MET inhibitor approved for the treatment of MET exon 14 (METex14) skipping NSCLC, demonstrated durable clinical activity in VISION (Cohort A + C; N = 313): objective response rate (ORR) 51.4% (95% CI: 45.8, 57.1); median duration of response (mDOR) 18.0 months (95% CI: 12.4, 46.4). We report outcomes in Asian patients from VISION (Cohort A + C) (cut-off: November 20, 2022). METHODS: Patients with advanced METex14 skipping NSCLC, detected by liquid or tissue biopsy, received tepotinib 500 mg (450 mg active moiety) once daily. PRIMARY ENDPOINT: objective response (RECIST 1.1) by independent review. Secondary endpoints included: DOR, progression-free survival (PFS), overall survival (OS), safety, and health-related quality of life (HRQoL). RESULTS: Across treatment lines in 106 Asian patients (39.6% female, 43.4% smoking history, 79.2% adenocarcinoma, 47.2% treatment-naive), ORR was 56.6% (95% CI: 46.6, 66.2), mDOR 18.5 months (10.4, ne), mPFS 13.8 months (10.8, 22.0), and mOS 25.5 months (19.3, 36.4). Consistent efficacy observed, regardless of baseline characteristics. HRQoL remained stable during treatment. Treatment-related adverse events (TRAEs) occurred in 95.3% of patients (39.6% Grade ≥3). Most common TRAEs: peripheral edema (62.3%), creatinine increase (38.7%). CONCLUSIONS: Tepotinib demonstrated robust and durable efficacy, with a manageable safety profile, in Asian patients with METex14 skipping NSCLC. CLINICAL TRIAL REGISTRATION: NCT02864992.

Long-term experience with tepotinib in Japanese patients with MET exon 14 skipping NSCLC from the Phase II VISION study.

Tepotinib is a highly selective MET tyrosine kinase inhibitor (TKI) that has demonstrated robust and durable clinical activity in patients with MET exon 14 (METex14) skipping non-small-cell lung cancer (NSCLC). In the Phase II VISION study, patients received oral tepotinib 500 mg once daily. The primary endpoint was an objective response by an independent review committee (IRC) according to RECIST v1.1 criteria. The secondary endpoints included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Here we report the analysis of the efficacy and safety of tepotinib in all Japanese patients with advanced METex14 skipping NSCLC from VISION (n = 38) with >18 months' follow-up. The median age of the Japanese patients was 73 years (range 63-88), 39.5% of patients were ≥75 years old, 68.4% were male, 55.3% had a history of smoking, 76.3% had adenocarcinoma, and 10.5% of patients had known brain metastases at baseline. Overall, the objective response rate (ORR) was 60.5% (95% confidence interval (CI): 43.4, 76.0) with a median DOR of 18.5 months (95% CI: 8.3, not estimable). ORR in treatment-naïve patients (n = 18) was 77.8% (95% CI: 52.4, 93.6), and in patients aged ≥75 years (n = 15), ORR was 73.3% (95% CI: 44.9, 92.2). The most common treatment-related adverse event (AE) with any grade was blood creatinine increase (65.8%), which resolved following tepotinib discontinuation. Other common treatment-related AEs were peripheral edema (60.5%), hypoalbuminemia (34.2%), diarrhea (28.9%), and nausea (15.8%). In summary, tepotinib demonstrated robust and durable clinical activity irrespective of age or therapy line, with a manageable safety profile in Japanese patients with METex14 skipping NSCLC enrolled in VISION.

Tepotinib in patients with non-small cell lung cancer with high-level MET amplification detected by liquid biopsy: VISION Cohort B.

High-level MET amplification (METamp) is a primary driver in ∼1%-2% of non-small cell lung cancers (NSCLCs). Cohort B of the phase 2 VISION trial evaluates tepotinib, an oral MET inhibitor, in patients with advanced NSCLC with high-level METamp who were enrolled by liquid biopsy. While the study was halted before the enrollment of the planned 60 patients, the results of 24 enrolled patients are presented here. The objective response rate (ORR) is 41.7% (95% confidence interval [CI], 22.1-63.4), and the median duration of response is 14.3 months (95% CI, 2.8-not estimable). In exploratory biomarker analyses, focal METamp, RB1 wild-type, MYC diploidy, low circulating tumor DNA (ctDNA) burden at baseline, and early molecular response are associated with better outcomes. Adverse events include edema (composite term; any grade: 58.3%; grade 3: 12.5%) and constipation (any grade: 41.7%; grade 3: 4.2%). Tepotinib provides antitumor activity in high-level METamp NSCLC (ClinicalTrials.gov: NCT02864992).

Tepotinib Treatment in Patients With MET Exon 14-Skipping Non-Small Cell Lung Cancer: Long-term Follow-up of the VISION Phase 2 Nonrandomized Clinical Trial.

Importance: MET inhibitors have recently demonstrated clinical activity in patients with MET exon 14 (METex14)-skipping non-small cell lung cancer (NSCLC); however, data with longer follow-up and in larger populations are needed to further optimize therapeutic approaches. Objective: To assess the long-term efficacy and safety of tepotinib, a potent and highly selective MET inhibitor, in patients with METex14-skipping NSCLC in the VISION study. Design, Setting, and Participants: The VISION phase 2 nonrandomized clinical trial was a multicohort, open-label, multicenter study that enrolled patients with METex14-skipping advanced/metastatic NSCLC (cohorts A and C) from September 2016 to May 2021. Cohort C (>18 months' follow-up) was an independent cohort, designed to confirm findings from cohort A (>35 months' follow-up). Data cutoff was November 20, 2022. Intervention: Patients received tepotinib, 500 mg (450 mg active moiety), once daily. Main Outcomes and Measures: The primary end point was objective response by independent review committee (RECIST v1.1). Secondary end points included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Results: Cohorts A and C included 313 patients (50.8% female, 33.9% Asian; median [range] age, 72 [41-94] years). The objective response rate (ORR) was 51.4% (95% CI, 45.8%-57.1%) with a median (m)DOR of 18.0 (95% CI, 12.4-46.4) months. In cohort C (n = 161), an ORR of 55.9% (95% CI, 47.9%-63.7%) with an mDOR of 20.8 (95% CI, 12.6-not estimable [NE]) months was reported across treatment lines, comparable to cohort A (n = 152). In treatment-naive patients (cohorts A and C; n = 164), ORR was 57.3% (95% CI, 49.4%-65.0%) and mDOR was 46.4 (95% CI, 13.8-NE) months. In previously treated patients (n = 149), ORR was 45.0% (95% CI, 36.8%-53.3%) and mDOR was 12.6 (95% CI, 9.5-18.5) months. Peripheral edema, the most common treatment-related adverse event, occurred in 210 patients (67.1%) (35 [11.2%] experienced grade ≥3 events). Conclusions and Relevance: The findings from cohort C in this nonrandomized clinical trial supported the results from original cohort A. Overall, the long-term outcomes of VISION demonstrated robust and durable clinical activity following treatment with tepotinib, particularly in the treatment-naive setting, in the largest known clinical trial of patients with METex14-skipping NSCLC, supporting the global approvals of tepotinib and enabling clinicians to implement this therapeutic approach for such patients. Trial Registration: ClinicalTrials.gov Identifier: NCT02864992.

Randomized Trial of Tepotinib Plus Gefitinib versus Chemotherapy in EGFR-Mutant NSCLC with EGFR Inhibitor Resistance Due to MET Amplification: INSIGHT Final Analysis.

PURPOSE: The final analyses of the INSIGHT phase II study evaluating tepotinib (a selective MET inhibitor) plus gefitinib versus chemotherapy in patients with MET-altered EGFR-mutant NSCLC (data cut-off: September 3, 2021). PATIENTS AND METHODS: Adults with advanced/metastatic EGFR-mutant NSCLC, acquired resistance to first-/second-generation EGFR inhibitors, and MET gene copy number (GCN) ≥5, MET:CEP7 ≥2, or MET IHC 2+/3+ were randomized to tepotinib 500 mg (450 mg active moiety) plus gefitinib 250 mg once daily, or chemotherapy. Primary endpoint was investigator-assessed progression-free survival (PFS). MET-amplified subgroup analysis was preplanned. RESULTS: Overall (N = 55), median PFS was 4.9 months versus 4.4 months [stratified HR, 0.67; 90% CI, 0.35-1.28] with tepotinib plus gefitinib versus chemotherapy. In 19 patients with MET amplification (median age 60.4 years; 68.4% never-smokers; median GCN 8.8; median MET/CEP7 2.8; 89.5% with MET IHC 3+), tepotinib plus gefitinib improved PFS (HR, 0.13; 90% CI, 0.04-0.43) and overall survival (OS; HR, 0.10; 90% CI, 0.02-0.36) versus chemotherapy. Objective response rate was 66.7% with tepotinib plus gefitinib versus 42.9% with chemotherapy; median duration of response was 19.9 months versus 2.8 months. Median duration of tepotinib plus gefitinib was 11.3 months (range, 1.1-56.5), with treatment >1 year in six (50.0%) and >4 years in three patients (25.0%). Seven patients (58.3%) had treatment-related grade ≥3 adverse events with tepotinib plus gefitinib and five (71.4%) had chemotherapy. CONCLUSIONS: Final analysis of INSIGHT suggests improved PFS and OS with tepotinib plus gefitinib versus chemotherapy in a subgroup of patients with MET-amplified EGFR-mutant NSCLC, after progression on EGFR inhibitors.

Tepotinib Efficacy and Safety in Patients with MET Exon 14 Skipping NSCLC: Outcomes in Patient Subgroups from the VISION Study with Relevance for Clinical Practice.

PURPOSE: Primary analysis of VISION showed tepotinib had durable clinical activity in patients with MET exon 14 (METex14) skipping non-small cell lung cancer (NSCLC). We present updated outcomes for clinically relevant subgroups. PATIENTS AND METHODS: This phase II, open-label, multi-cohort study of 500 mg (450 mg active moiety) tepotinib in patients with METex14 skipping NSCLC assessed efficacy and safety in predefined subgroups according to age, prior therapies (chemotherapy and immune checkpoint inhibitors), and brain metastases. An ad hoc retrospective analysis using Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria assessed intracranial activity. RESULTS: 152 patients were evaluable for efficacy (median age: 73.1). Overall, objective response rate (ORR) was 44.7% [95% confidence interval (CI): 36.7-53.0]. Patients aged <75 (n = 84) and ≥75 (n = 68) had ORRs of 48.8% (95% CI: 37.7-60.0) and 39.7% (95% CI: 28.0-52.3), respectively. Treatment-naïve (n = 69) versus previously treated (n = 83) patients showed consistent efficacy [ORR (95% CI): 44.9% (32.9-57.4) vs. 44.6% (33.7-55.9); median duration of response (95% CI): 10.8 (6.9-not estimable) vs. 11.1 (9.5-18.5) months]. Of 15 patients analyzed by RANO-BM (12 received prior radiotherapy), 13 achieved intracranial disease control; 5 of 7 patients with measurable brain metastases had partial intracranial responses. Of 255 patients evaluable for safety, 64 (25.1%) experienced grade ≥3 treatment-related adverse events (TRAE), leading to discontinuation in 27 patients (10.6%). Rates of adverse events (AE) were broadly consistent irrespective of prior therapies. CONCLUSIONS: Tepotinib showed meaningful activity across subgroups by age, prior therapies, and brain metastases, with a manageable safety profile and few treatment discontinuations. See related commentary by Rosner and Spira, p. 1055.

Tepotinib in patients with NSCLC harbouring MET exon 14 skipping: Japanese subset analysis from the Phase II VISION study.

BACKGROUND: MET exon 14 skipping is an oncogenic driver occurring in 3-4% of non-small cell lung cancer (NSCLC). The MET inhibitor tepotinib has demonstrated clinical efficacy in patients with MET exon 14 skipping NSCLC. Here, we present data from Japanese patients in the Phase II VISION study, evaluating the efficacy and safety of tepotinib. METHODS: In the open-label, single-arm, Phase II VISION study, patients with advanced/metastatic NSCLC with MET exon 14 skipping received oral tepotinib 500 mg once daily. The primary endpoint was objective response by independent review. Subgroup analyses of Japanese patients were preplanned. RESULTS: As of 1 January 2020, 19 Japanese patients received tepotinib and were evaluated for safety, 15 of whom had ≥9 months' follow-up and were also analysed for efficacy. By independent review, objective response rate (ORR) was 60.0% (95% confidence interval [CI]: 32.3, 83.7), median duration of response was not reached (95% CI: 6.9, not estimable [ne]), and progression-free survival was 11.0 months (95% CI: 1.4, ne). ORR in patients with MET exon 14 skipping identified by liquid biopsy (n = 8) was 87.5% (95% CI: 47.3, 99.7), and by tissue biopsy (n = 12) was 50.0% (95% CI: 21.1, 78.9). Patients' quality of life was maintained with tepotinib treatment. Among patients evaluated for safety, the most common treatment-related adverse events (any grade) were blood creatinine increase and peripheral oedema (12 and nine patients, respectively). CONCLUSIONS: Tepotinib demonstrated robust and durable clinical efficacy in Japanese patients with advanced NSCLC harbouring MET exon 14 skipping, identified by either liquid or tissue biopsy. The main adverse events, blood creatinine increase and peripheral oedema, were manageable.

Phase 1b/2 trial of tepotinib in sorafenib pretreated advanced hepatocellular carcinoma with MET overexpression.

BACKGROUND: This Phase 1b/2 study evaluated tepotinib, a highly selective MET inhibitor, in US/European patients with sorafenib pretreated advanced hepatocellular carcinoma (aHCC) with MET overexpression. METHODS: Eligible adults had aHCC, progression after ≥4 weeks of sorafenib, and, for Phase 2 only, MET overexpression. Tepotinib was administered once daily at 300 or 500 mg in Phase 1b ('3 + 3' design), and at the recommended Phase 2 dose (RP2D) in Phase 2. Primary endpoints were dose-liming toxicities (DLTs; Phase 1b) and 12-week investigator-assessed progression-free survival (PFS; Phase 2). RESULTS: In Phase 1b (n = 17), no DLTs occurred and the RP2D was confirmed as 500 mg. In Phase 2 (n = 49), the primary endpoint was met: 12-week PFS was 63.3% (90% CI: 50.5-74.7), which was significantly greater than the predefined null hypothesis of ≤15% (one-sided binomial exact test: P < 0.0001). Median time to progression was 4 months. In Phase 2, 28.6% of patients had treatment-related Grade ≥3 adverse events, including peripheral oedema and lipase increase (both 6.1%). CONCLUSIONS: Tepotinib was generally well tolerated and the RP2D (500 mg) showed promising efficacy and, therefore, a positive benefit-risk balance in sorafenib pretreated aHCC with MET overexpression. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02115373.

Tepotinib plus gefitinib in patients with EGFR-mutant non-small-cell lung cancer with MET overexpression or MET amplification and acquired resistance to previous EGFR inhibitor (INSIGHT study): an open-label, phase 1b/2, multicentre, randomised trial.

BACKGROUND: We evaluated the efficacy and safety of tepotinib, a potent and highly selective oral MET inhibitor, plus gefitinib in patients with epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC) with MET overexpression (immunohistochemistry [IHC]2+ or IHC3+) or MET amplification having acquired resistance to EGFR inhibition. METHODS: In this open-label, phase 1b/2, multicentre, randomised trial (the INSIGHT study), we enrolled adult patients (≥18 years) with advanced or metastatic NSCLC, and Eastern Cooperative Oncology Group performance status of 0 or 1, from academic medical centres and community clinics in six Asian countries. In phase 1b, patients received oral tepotinib 300 mg or 500 mg plus gefitinib 250 mg once daily. In phase 2, patients with EGFR-mutant, T790M-negative NSCLC MET overexpression or MET amplification were randomly assigned (initially in a 1:1 ratio and then 2:1 following a protocol amendment) to tepotinib plus gefitinib at the recommended phase 2 dose or to standard platinum doublet chemotherapy. Randomisation was done centrally via an interactive voice-response system. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS) and safety. Subgroup analyses were preplanned in patients with high MET overexpression (IHC3+) or MET amplification (mean gene copy number ≥5 or MET to centromere of chromosome 7 ratio ≥2). Efficacy and patient characteristics were assessed on an intention-to-treat basis and safety was assessed for all patients who received at least one dose of study medication. Low recruitment led to early termination of phase 2, so all analyses are considered to be exploratory. This study is registered with ClinicalTrials.gov, NCT01982955, and the European Union Drug Regulating Authorities Clinical Trials Database, Eudra-CT 2016-001604-28. FINDINGS: From Dec 23, 2013, to May 25, 2017, 18 patients were enrolled in phase 1b (n=6 in the 300 mg tepotinib group; n=12 in the 500 mg tepotinib group) and 55 patients in phase 2 (n=31 in the tepotinib plus gefitinib group; n=24 in the chemotherapy group). No dose-limiting toxicities were observed in phase 1b, so tepotinib 500 mg was used as the recommended phase 2 dose. In phase 2, survival outcomes were similar between groups: median PFS was 4·9 months in the tepotinib plus gefitinib group (90% CI 3·9-6·9) versus 4·4 months in the chemotherapy group (90% CI 4·2-6·8; hazard ratio [HR] 0·67, 90% CI 0·35-1·28). Median OS was 17·3 months in the tepotinib plus gefitinib group (12·1-37·3) versus 18·7 months in the chemotherapy group (15·9-20·7; HR 0·69, 0·34-1·41). PFS and OS were longer with tepotinib plus gefitinib than with chemotherapy in patients with high (IHC3+) MET overexpression (n=34; median PFS 8·3 months [4·1-16·6] vs 4·4 months [4·1-6·8]; HR 0·35, 0·17-0·74; median OS 37·3 months [90% CI 24·2-37·3] vs 17·9 months [12·0-20·7]; HR 0·33, 0·14-0·76) or MET amplification (n=19; median PFS 16·6 months [8·3-not estimable] vs 4·2 months [1·4-7·0]; HR 0·13, 0·04-0·43; median OS 37·3 months [90% CI not estimable] vs 13·1 months [3·25-not estimable]; HR 0·08, 0·01-0·51). The most frequent treatment-related grade 3 or worse adverse events were increased amylase (5 [16%] of 31 patients) and lipase (4 [13%]) concentrations in the tepotinib plus gefitinib group and anaemia (7 [30%] of 23 patients) and decreased neutrophil count (3 [13%]) in the chemotherapy group. INTERPRETATION: Despite early study termination, in a preplanned subgroup analysis, our findings suggest improved anti activity for tepotinib plus gefitinib compared with standard chemotherapy in patients with EGFR-mutant NSCLC and MET amplification, warranting further exploration. FUNDING: Merck KGaA.

Tepotinib in Non-Small-Cell Lung Cancer with MET Exon 14 Skipping Mutations.

BACKGROUND: A splice-site mutation that results in a loss of transcription of exon 14 in the oncogenic driver MET occurs in 3 to 4% of patients with non-small-cell lung cancer (NSCLC). We evaluated the efficacy and safety of tepotinib, a highly selective MET inhibitor, in this patient population. METHODS: In this open-label, phase 2 study, we administered tepotinib (at a dose of 500 mg) once daily in patients with advanced or metastatic NSCLC with a confirmed MET exon 14 skipping mutation. The primary end point was the objective response by independent review among patients who had undergone at least 9 months of follow-up. The response was also analyzed according to whether the presence of a MET exon 14 skipping mutation was detected on liquid biopsy or tissue biopsy. RESULTS: As of January 1, 2020, a total of 152 patients had received tepotinib, and 99 patients had been followed for at least 9 months. The response rate by independent review was 46% (95% confidence interval [CI], 36 to 57), with a median duration of response of 11.1 months (95% CI, 7.2 to could not be estimated) in the combined-biopsy group. The response rate was 48% (95% CI, 36 to 61) among 66 patients in the liquid-biopsy group and 50% (95% CI, 37 to 63) among 60 patients in the tissue-biopsy group; 27 patients had positive results according to both methods. The investigator-assessed response rate was 56% (95% CI, 45 to 66) and was similar regardless of the previous therapy received for advanced or metastatic disease. Adverse events of grade 3 or higher that were considered by investigators to be related to tepotinib therapy were reported in 28% of the patients, including peripheral edema in 7%. Adverse events led to permanent discontinuation of tepotinib in 11% of the patients. A molecular response, as measured in circulating free DNA, was observed in 67% of the patients with matched liquid-biopsy samples at baseline and during treatment. CONCLUSIONS: Among patients with advanced NSCLC with a confirmed MET exon 14 skipping mutation, the use of tepotinib was associated with a partial response in approximately half the patients. Peripheral edema was the main toxic effect of grade 3 or higher. (Funded by Merck [Darmstadt, Germany]; VISION ClinicalTrials.gov number, NCT02864992.).

First-in-Man Phase I Trial of the Selective MET Inhibitor Tepotinib in Patients with Advanced Solid Tumors.

PURPOSE: Tepotinib is an oral, potent, highly selective MET inhibitor. This first-in-man phase I trial investigated the MTD of tepotinib to determine the recommended phase II dose (RP2D). PATIENTS AND METHODS: Patients received tepotinib orally according to one of three dose escalation regimens (R) on a 21-day cycle: R1, 30-400 mg once daily for 14 days; R2, 30-315 mg once daily 3 times/week; or R3, 300-1,400 mg once daily. After two cycles, treatment could continue in patients with stable disease until disease progression or unacceptable toxicity. The primary endpoint was incidence of dose-limiting toxicity (DLT) and treatment-emergent adverse events (TEAE). Secondary endpoints included safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor effects. RESULTS: One hundred and forty-nine patients received tepotinib (R1: n = 42; R2: n = 45; R3: n = 62). Although six patients reported DLTs [one patient in R1 (115 mg), three patients in R2 (60, 100, 130 mg), two patients in R3 (1,000, 1,400 mg)], the MTD was not reached at the highest tested dose of 1,400 mg daily. The RP2D of tepotinib was established as 500 mg once daily, supported by translational modeling data as sufficient to achieve ≥95% MET inhibition in ≥90% of patients. Treatment-related TEAEs were mostly grade 1 or 2 fatigue, peripheral edema, decreased appetite, nausea, vomiting, and lipase increase. The best overall response in R3 was partial response in two patients, both with MET overexpression. CONCLUSIONS: Tepotinib was well tolerated with clinical activity in MET-dysregulated tumors. The RP2D of tepotinib was established as 500 mg once daily. MET abnormalities can drive tumorigenesis. This first-in-man trial demonstrated that the potent, highly selective MET inhibitor tepotinib can reduce or stabilize tumor burden and is well tolerated at doses up to 1,400 mg once daily. An RP2D of 500 mg once daily, as determined from translational modeling and simulation integrating human population pharmacokinetic and pharmacodynamic data in tumor biopsies, is being used in ongoing clinical trials.

Differential Effect on Bone Lesions of Targeting Integrins: Randomized Phase II Trial of Abituzumab in Patients with Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Integrins play a critical role in the progression of prostate cancer and its bone metastases. We investigated the use of the pan-αv integrin inhibitor abituzumab in chemotherapy-naïve patients with asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer. EXPERIMENTAL DESIGN: PERSEUS (NCT01360840) was a randomized, double-blind phase II study. Men with pathologically confirmed prostate cancer and radiologic progression of bone lesions in the 28 days prior to randomization were assigned to receive abituzumab 750 mg or 1,500 mg or placebo (1:1:1) every 3 weeks in combination with luteinizing hormone-releasing hormone agonist/antagonist therapy. The primary endpoint was progression-free survival (PFS). RESULTS: The intent-to-treat population comprised 180 patients, 60 in each arm. The primary endpoint of PFS was not significantly different with abituzumab-based therapy compared with placebo [abituzumab 750 mg, 3.4 months, HR = 0.89; 95% confidence interval (CI), 0.57-1.39; abituzumab 1,500 mg, 4.3 months, HR = 0.81; 95% CI, 0.52-1.26; placebo, 3.3 months], but the cumulative incidence of bone lesion progression was lower with abituzumab than with placebo for up to 24 months (cumulative incidence 23.6% vs. 41.1% at 6 months, 26.1% vs. 45.4% at 12 months). Two partial tumor responses were observed (1 abituzumab 1,500 mg and 1 placebo). Approximately 85% to 90% of patients experienced at least one treatment-emergent adverse event (TEAE) in the different arms, but the incidences of serious TEAEs and TEAEs with fatal outcome were similar in the three arms. CONCLUSIONS: Although PFS was not significantly extended, abituzumab appears to have specific activity in prostate cancer-associated bone lesions that warrants further investigation. Clin Cancer Res; 22(13); 3192-200. ©2016 AACR.