The clinical KRAS(G12C) inhibitor AMG 510 drives anti-tumour immunity.

KRAS is the most frequently mutated oncogene in cancer and encodes a key signalling protein in tumours1,2. The KRAS(G12C) mutant has a cysteine residue that has been exploited to design covalent inhibitors that have promising preclinical activity3-5. Here we optimized a series of inhibitors, using novel binding interactions to markedly enhance their potency and selectivity. Our efforts have led to the discovery of AMG 510, which is, to our knowledge, the first KRAS(G12C) inhibitor in clinical development. In preclinical analyses, treatment with AMG 510 led to the regression of KRASG12C tumours and improved the anti-tumour efficacy of chemotherapy and targeted agents. In immune-competent mice, treatment with AMG 510 resulted in a pro-inflammatory tumour microenvironment and produced durable cures alone as well as in combination with immune-checkpoint inhibitors. Cured mice rejected the growth of isogenic KRASG12D tumours, which suggests adaptive immunity against shared antigens. Furthermore, in clinical trials, AMG 510 demonstrated anti-tumour activity in the first dosing cohorts and represents a potentially transformative therapy for patients for whom effective treatments are lacking.

Sotorasib for Lung Cancers with KRAS p.G12C Mutation.

BACKGROUND: Sotorasib showed anticancer activity in patients with KRAS p.G12C-mutated advanced solid tumors in a phase 1 study, and particularly promising anticancer activity was observed in a subgroup of patients with non-small-cell lung cancer (NSCLC). METHODS: In a single-group, phase 2 trial, we investigated the activity of sotorasib, administered orally at a dose of 960 mg once daily, in patients with KRAS p.G12C-mutated advanced NSCLC previously treated with standard therapies. The primary end point was objective response (complete or partial response) according to independent central review. Key secondary end points included duration of response, disease control (defined as complete response, partial response, or stable disease), progression-free survival, overall survival, and safety. Exploratory biomarkers were evaluated for their association with response to sotorasib therapy. RESULTS: Among the 126 enrolled patients, the majority (81.0%) had previously received both platinum-based chemotherapy and inhibitors of programmed death 1 (PD-1) or programmed death ligand 1 (PD-L1). According to central review, 124 patients had measurable disease at baseline and were evaluated for response. An objective response was observed in 46 patients (37.1%; 95% confidence interval [CI], 28.6 to 46.2), including in 4 (3.2%) who had a complete response and in 42 (33.9%) who had a partial response. The median duration of response was 11.1 months (95% CI, 6.9 to could not be evaluated). Disease control occurred in 100 patients (80.6%; 95% CI, 72.6 to 87.2). The median progression-free survival was 6.8 months (95% CI, 5.1 to 8.2), and the median overall survival was 12.5 months (95% CI, 10.0 to could not be evaluated). Treatment-related adverse events occurred in 88 of 126 patients (69.8%), including grade 3 events in 25 patients (19.8%) and a grade 4 event in 1 (0.8%). Responses were observed in subgroups defined according to PD-L1 expression, tumor mutational burden, and co-occurring mutations in STK11, KEAP1, or TP53. CONCLUSIONS: In this phase 2 trial, sotorasib therapy led to a durable clinical benefit without new safety signals in patients with previously treated KRAS p.G12C-mutated NSCLC. (Funded by Amgen and the National Institutes of Health; CodeBreaK100 ClinicalTrials.gov number, NCT03600883.).

KRASG12C Inhibition with Sotorasib in Advanced Solid Tumors.

BACKGROUND: No therapies for targeting KRAS mutations in cancer have been approved. The KRAS p.G12C mutation occurs in 13% of non-small-cell lung cancers (NSCLCs) and in 1 to 3% of colorectal cancers and other cancers. Sotorasib is a small molecule that selectively and irreversibly targets KRASG12C. METHODS: We conducted a phase 1 trial of sotorasib in patients with advanced solid tumors harboring the KRAS p.G12C mutation. Patients received sotorasib orally once daily. The primary end point was safety. Key secondary end points were pharmacokinetics and objective response, as assessed according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. RESULTS: A total of 129 patients (59 with NSCLC, 42 with colorectal cancer, and 28 with other tumors) were included in dose escalation and expansion cohorts. Patients had received a median of 3 (range, 0 to 11) previous lines of anticancer therapies for metastatic disease. No dose-limiting toxic effects or treatment-related deaths were observed. A total of 73 patients (56.6%) had treatment-related adverse events; 15 patients (11.6%) had grade 3 or 4 events. In the subgroup with NSCLC, 32.2% (19 patients) had a confirmed objective response (complete or partial response) and 88.1% (52 patients) had disease control (objective response or stable disease); the median progression-free survival was 6.3 months (range, 0.0+ to 14.9 [with + indicating that the value includes patient data that were censored at data cutoff]). In the subgroup with colorectal cancer, 7.1% (3 patients) had a confirmed response, and 73.8% (31 patients) had disease control; the median progression-free survival was 4.0 months (range, 0.0+ to 11.1+). Responses were also observed in patients with pancreatic, endometrial, and appendiceal cancers and melanoma. CONCLUSIONS: Sotorasib showed encouraging anticancer activity in patients with heavily pretreated advanced solid tumors harboring the KRAS p.G12C mutation. Grade 3 or 4 treatment-related toxic effects occurred in 11.6% of the patients. (Funded by Amgen and others; CodeBreaK100 ClinicalTrials.gov number, NCT03600883.).

Sotorasib for previously treated colorectal cancers with KRASG12C mutation (CodeBreaK100): a prespecified analysis of a single-arm, phase 2 trial.

BACKGROUND: Sotorasib, a specific, irreversible KRASG12C protein inhibitor, has shown monotherapy clinical activity in KRASG12C-mutated solid tumours, including colorectal cancer, in the CodeBreaK100 phase 1 trial. We aimed to investigate the activity and safety of sotorasib in phase 2 of the trial. METHODS: In this single-arm, phase 2 trial, adult patients with KRASG12C-mutated advanced solid tumours were enrolled, from 59 medical centres in 11 countries, if they were aged 18 years or older, had at least one measurable lesion according to the Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1, and had an Eastern Cooperative Oncology Group performance status of 1 or lower. Only data for patients with colorectal cancer, enrolled at 33 medical centres in nine countries, are presented from this basket trial. To be enrolled, the patients had to have progressed after receiving fluoropyrimidine, oxaliplatin, and irinotecan treatment. These patients were administered 960 mg sotorasib orally once per day until disease progression, development of unacceptable side-effects, withdrawal of consent, or death. The primary endpoint was objective response (complete or partial response) as assessed by blinded independent central review. Response was evaluated in patients who received at least one dose of sotorasib and had at least one measurable lesion at baseline; safety was evaluated in patients who received at least one dose of sotorasib. This analysis is a prespecified analysis triggered by the phase 2 colorectal cancer cohort. This study is registered with ClinicalTrials.gov, NCT03600883, and is active but no longer recruiting. FINDINGS: On March 1, 2021, at data cutoff, 62 patients with KRASG12C-mutant colorectal cancer had been enrolled between Aug 14, 2019, and May 21, 2020, and had received at least one dose of sotorasib monotherapy. Objective response was observed in six (9·7%, 95% CI 3·6-19·9) of 62 patients, all with partial response. Treatment-related adverse events at grade 3 occurred in six (10%) patients, the most common of which was diarrhoea (two [3%] of 62 patients), and at grade 4 occurred in one (2%) patient (blood creatine phosphokinase increase); no fatal events were recorded. Serious treatment-related adverse events occurred in two (3%) patients (back pain and acute kidney injury). INTERPRETATION: Although the 9·7% overall response rate did not reach the benchmark, oral administration of sotorasib once per day showed modest anti-tumour activity and manageable safety in these heavily pretreated chemorefractory patients. Sotorasib is under evaluation in combination with other therapeutics to increase potential activity and overcome potential resistance mechanisms. FUNDING: Amgen.

Targeting wild-type TP53 using AMG 232 in combination with MAPK inhibition in Metastatic Melanoma; a phase 1 study.

BACKGROUND: Targeting the MDM2-p53 interaction using AMG 232 is synergistic with MAPK inhibitors (MAPKi) in preclinical melanoma models. We postulated that AMG 232 plus MAPKi is safe and more effective than MAPKi alone in TP53-wild type, MAPKi-naïve metastatic melanoma. METHODS: Patients were treated with increasing (120 mg, 180 mg, 240 mg) oral doses of AMG 232 (seven-days-on, 15-days-off, 21-day cycle) plus dabrafenib (D) and trametinib (T) (Arm 1, BRAFV600-mutant) or T alone (Arm 2, BRAFV600-wild type). Patients were treated for seven days with AMG 232 alone before adding T±D. Safety and efficacy were assessed using CTCAE v4.0 and RECIST v1.1 criteria, respectively. Pharmacokinetic (PK) analysis was performed at baseline and steady-state levels for AMG 232. RESULTS: 31 patients were enrolled. Ten and 21 patients were enrolled in Arm 1 and Arm 2, respectively. The most common AMG 232-related adverse events (AEs) were nausea (87%), diarrhea (77%), and fatigue (74%). Seven patients (23%) were withdrawn from the study due to AMG 232-related AEs. Three dose-limiting AEs occurred (Arm 1, 180 mg, nausea; Arm 2, 240 mg, grade 3 pulmonary embolism; Arm 2, 180 mg, grade 4 thrombocytopenia). AMG 232 PK exposures were not altered when AMG 232 was combined with T±D. Objective responses were seen in 8/10 (Arm 1) and 3/20 (Arm 2) evaluable patients. The median progression-free survival for Arm 1 and Arm 2 was 19.0 months-not reached and 2.8 months, respectively. CONCLUSION: The maximum tolerated dose of AMG 232 for both arms was 120 mg. AMG 232 plus T±D exhibited a favorable PK profile. Although objective responses occurred in both arms, adding AMG 232 to T±D did not confer additional clinical benefit.

Phase 1 study of the MDM2 inhibitor AMG 232 in patients with advanced P53 wild-type solid tumors or multiple myeloma.

Background This open-label, first-in-human, phase 1 study evaluated AMG 232, an oral selective MDM2 inhibitor in patients with TP53 wild-type (P53WT), advanced solid tumors or multiple myeloma (MM). Methods In the dose escalation (n = 39), patients with P53WT refractory solid tumors enrolled to receive once-daily AMG 232 (15, 30, 60, 120, 240, 480, and 960 mg) for seven days every 3 weeks (Q3W). In the dose expansion (n = 68), patients with MDM2-amplified (well-differentiated and de-differentiated liposarcomas [WDLPS and DDLPS], glioblastoma multiforme [GBM], or other solid tumors [OST]), MDM2-overexpressing ER+ breast cancer (BC), or MM received AMG 232 at the maximum tolerated dose (MTD). Safety, pharmacokinetics, pharmacodynamics, and efficacy were assessed. Results AMG 232 had acceptable safety up to up to 240 mg. Three patients had dose-limiting toxicities of thrombocytopenia (n = 2) and neutropenia (n = 1). Due to these and other delayed cytopenias, AMG 232 240 mg Q3W was determined as the highest tolerable dose assessed in the dose expansion. Adverse events were typically mild/moderate and included diarrhea, nausea, vomiting, fatigue, decreased appetite, and anemia. AMG 232 plasma concentrations increased dose proportionally. Increases in serum macrophage inhibitor cytokine-1 from baseline were generally dose dependent, indicating p53 pathway activation. Per local review, there were no responses. Stable disease (durability in months) was observed in patients with WDLPS (3.9), OST (3.3), DDLPS (2.0), GBM (1.8), and BC (1.4-2.0). Conclusions In patients with P53WT advanced solid tumors or MM, AMG 232 showed acceptable safety and dose-proportional pharmacokinetics, and stable disease was observed.

Phase 2 study of granulocyte-macrophage colony-stimulating factor plus thalidomide in patients with hormone-naïve adenocarcinoma of the prostate.

OBJECTIVE: To assess the efficacy of granulocyte macrophage colony-stimulating factor (GM-CSF) in combination with thalidomide on prostate-specific antigen (PSA) reduction in hormone-naïve prostate carcinoma (HNPC) patients with rising PSA levels after definitive local treatment. MATERIALS AND METHODS: HNPC patients (n = 21) with evidence of progression demonstrated by 3 consecutive rises in PSA and no evidence of radiographic involvement were treated on a chronic dosing schedule with GM-CSF. Patients received 250 microg/m2 (maximum 500 microg) 3 times a wk by subcutaneous injection, with injections at least 24 h apart. Thalidomide administration began concurrently with an initial dose of 100 mg daily for 7 consecutive days. During wk 2 to 4, the dose was escalated every 7 d by 100 mg per individual tolerance to a maximum of 400 mg. The maximum tolerated dose of thalidomide was continued without interruption. PSA, testosterone, and routine laboratory parameters were measured every 6 wk. RESULTS: One patient was not evaluable because of noncompliance. For the 20 evaluable patients, baseline PSA levels ranged from 1.3 to 61.0 ng/ml. Nineteen patients left the study at 3.0 to 33.3 mo, secondary to individual tolerance, progressive disease, or development of a second primary tumor. One patient continues to receive therapy at 33.8 mo. Two patients did not respond to the therapy. For the 18 patients who did respond, the median reduction in PSA level was 59% (range 26%-89%), and the median duration of response was 11 mo (range 4.5-36). Grades 1-2 toxicity included peripheral neuropathy, fatigue, skin rash, and constipation. One patient had deep-vein thrombosis/pulmonary embolism. CONCLUSIONS: GM-CSF plus thalidomide can be administered successfully with encouraging antitumor activity and reversible toxicity. This may represent an alternative to hormonal therapy.

A retrospective review of combination chemohormonal therapy as initial treatment for locally advanced or metastatic adenocarcinoma of the prostate.

OBJECTIVE: Chemotherapy for hormone-refractory prostate cancer reduces PSA levels and enhances overall survival (OS), suggesting that administration in earlier disease stages may be beneficial. If expansion of an androgen-independent clone present during androgen deprivation mediates the transformation from an androgen-dependent to an androgen-independent phenotype, combination chemohormonal therapy would be effective initial treatment for locally advanced or metastatic prostate cancers. A retrospective review was conducted to evaluate results. MATERIALS AND METHODS: Chemohormonal therapy outcomes were retrospectively evaluated in men with locally advanced or metastatic prostate cancer seen at our institution between January 2001 and February 2003. Chemotherapy consisted of three 8-week cycles (once weekly intravenous doxorubicin 20 mg/m(2) and thrice daily oral ketoconazole 400 mg in weeks 1, 3, and 5; once weekly intravenous docetaxel 35 mg/m(2) and thrice daily oral estramustine 280 mg in weeks 2, 4, and 6; and no therapy in weeks 7 and 8). Hormone therapy consisted of hormonal ablation during and after antiandrogen therapy after chemotherapy. RESULTS: Data for 31 men (median age, 63 years [range, 41-74 years]; white, 97% [30/31]) were reviewed. At 1 year, median PSA level had fallen 99.3% (range, 91.7%-99.9%) from a baseline value of 14.3 ng/ml (range, 1.9-497.9 ng/mL). Median time to progression was 34+ months (range, 14-68+ months). Median OS was 56+ months (range, 17-73+ months). CONCLUSIONS: Combination chemohormonal therapy for locally advanced or metastatic prostate cancer safely and effectively reduces PSA levels and increases OS. We are now testing this approach in a prospective, Phase II randomized clinical trial.

First-in-human study to assess safety, tolerability, pharmacokinetics, and pharmacodynamics of the anti-CD27L antibody-drug conjugate AMG 172 in patients with relapsed/refractory renal cell carcinoma.

PURPOSE: This study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of the anti-CD27L antibody-drug conjugate AMG 172 in patients with relapsed/refractory clear cell renal cell carcinoma (ccRCC). METHODS: This was an open-label, adaptive dose-exploration study in patients with relapsed/refractory ccRCC. The study was conducted in two parts for dose exploration and dose expansion on a biweekly dosing schedule. AMG 172 doses of 0.15, 0.3, 0.6, 1.2, 1.6, 1.8, and 2.4 mg/kg were studied in the dose-exploration phase. RESULTS: The 1.6 mg/kg dose of AMG 172 was identified as the maximum tolerated dose (MTD). The most common adverse events were thrombocytopenia (59%), nausea (54%), decreased appetite (49%), vomiting (46%), and fatigue (35%). The most common dose-limiting toxicity (DLT) was thrombocytopenia. Thrombocytopenia and liver injury constituted DLTs that required discontinuation of treatment. Of the 10 patients treated at the MTD in part 2 of the study, 2 patients had grade 3 hepatocellular injury with aspartate aminotransferase or alanine aminotransferase elevation. Pharmacokinetic profiles indicated low levels of circulating unconjugated antibody and unconjugated cytotoxin. Dose-proportional increases in plasma exposure were observed over the dose range of 0.3-2.4 mg/kg. Following multiple biweekly doses, plasma accumulation was less than two-fold. Two patients (5.4%) had a partial response, 6 patients (16.2%) had stable disease, and 13 patients (35.1%) had progressive disease. CONCLUSION: AMG 172 exhibited a favorable pharmacokinetic profile in patients with relapsed/refractory ccRCC and showed evidence suggestive of limited antitumor activity. Safety and tolerability were as expected for a maytansinoid antibody-drug conjugate.

Safety, tolerability, and pharmacokinetics of anti-EGFRvIII antibody-drug conjugate AMG 595 in patients with recurrent malignant glioma expressing EGFRvIII.

PURPOSE: Epidermal growth factor receptor variant III (EGFRvIII) is expressed in a significant percentage of primary and recurrent glioblastoma (GBM), a common malignant primary brain tumor in adults. AMG 595 is an antibody-drug conjugate comprising a fully human, anti-EGFRvIII monoclonal antibody linked to DM1. The study goals were to assess safety, tolerability, and pharmacokinetics of AMG 595 in GBM. METHODS: In this phase 1, first-in-human, open-label, sequential-dose, exploration study, adults with recurrent GBM received AMG 595 once every 3 weeks (Q3W) according to incremental dosing cohorts (0.5-3.0 mg/kg). Primary endpoints were to assess safety, the incidence of dose-limiting toxicities (DLTs), objective response (per Macdonald criteria), evaluate pharmacokinetics, and estimate the maximum tolerated dose (MTD). RESULTS: Of 382 patients screened, 32 were enrolled and received ≥ 1 dose of AMG 595. Ten patients experienced 18 DLTs (all grade 4 thrombocytopenia), and the MTD was 2.0 mg/kg. Twenty-eight patients (88%) experienced ≥ 1 treatment-related adverse event (AE); the most common AEs were thrombocytopenia (50%) and fatigue (25%). Grade ≥ 3 treatment-related AEs occurred in 17 patients (53%); 11 (34%) had serious treatment-emergent AEs, and none were considered treatment related. Pharmacokinetic profiles indicated low levels of circulating unconjugated antibody and cytotoxin, dose-proportional increases in plasma exposures for the conjugated antibody over the studied range, and less than twofold accumulation following multiple Q3W dosing. Two patients (6%) had partial responses; 15 (47%) had stable disease. CONCLUSIONS: AMG 595 exhibited favorable pharmacokinetics and is a unique therapy with possible benefit for some patients with EGFRvIII-mutated GBM with limited therapeutic options.

Phase 1b study of the MDM2 inhibitor AMG 232 with or without trametinib in relapsed/refractory acute myeloid leukemia.

This open-label, phase 1 study evaluated the safety, pharmacokinetics, and maximum tolerated dose of AMG 232, an investigational oral, selective mouse double minute 2 homolog inhibitor in relapsed/refractory acute myeloid leukemia (AML). AMG 232 was administered orally once daily for 7 days every 2 weeks (7 on/off) at 60, 120, 240, 360, 480, or 960 mg as monotherapy (arm 1) or at 60 mg with trametinib 2 mg (arm 2). Dose-limiting toxicities (DLTs), adverse events (AEs), pharmacokinetics, clinical and pharmacodynamic response, and expression of p53 target genes were assessed. All 36 patients received AMG 232. No DLTs occurred in arm 1, and 360 mg was the highest test dose; dose escalation was halted due to gastrointestinal AEs at higher doses. One of ten patients in arm 2 had a DLT (grade 3 fatigue); 60 mg was the highest dose tested with trametinib. Common treatment-related AEs (any grade) included nausea (58%), diarrhea (56%), vomiting (33%), and decreased appetite (25%). AMG 232 exhibited linear pharmacokinetics unaffected by coadministration with trametinib. Serum macrophage inhibitor cytokine-1 and bone marrow expression of BAX, PUMA, P21, and MDM2 increased during treatment. Of 30 evaluable patients, 1 achieved complete remission, 4 had morphologic leukemia-free state, and 1 had partial remission. Four of 13 (31%) TP53-wild-type patients and 0 of 3 (0%) TP53-mutant patients were responders. AMG 232 was associated with gastrointestinal AEs at higher doses but had acceptable pharmacokinetics, on-target effects, and promising clinical activity warranting further investigation in patients with relapsed/refractory AML. This trial was registered at www.clinicaltrials.gov as #NCT02016729.

Bone-targeted therapy: phase II study of strontium-89 in combination with alternating weekly chemohormonal therapies for patients with advanced androgen-independent prostate cancer.

OBJECTIVES: Bone-targeted therapy that combines strontium-89 (Sr-89) with alternating weekly chemohormonal therapy may improve clinical outcomes in patients with metastatic hormone-refractory prostate cancer. This phase II study investigated the addition of Sr-89 to an alternating weekly regimen of doxorubicin and ketoconazole with paclitaxel and estramustine in patients with progressive prostate cancer and bone involvement. METHODS: Twenty-nine patients with progressive adenocarcinoma of the prostate and osteoblastic bone metastases who failed conventional hormonal therapy were registered for the study. Of those, 27 were treated with Sr-89 on day 1 of week 1. On weeks 1, 3, and 5, patients received doxorubicin (20 mg/m on day 1) and oral ketoconazole (400 mg 3 times a day for 7 days). On weeks 2, 4, and 6, patients received paclitaxel (100 mg/m(2)) and oral estramustine (280 mg 3 times a day for 7 days). No treatment was given during weeks 7 and 8. Cycles were repeated every 8 weeks. RESULTS: A > or =50% reduction in prostate-specific antigen level was maintained for at least 8 weeks in 77.7% of the patients (21 patients) at 16 weeks and in 66.6% (18 patients) at 32 weeks. The median progression-free survival was 11.27 months (range, 1.83-29.53), and the median overall survival was 22.67 months (1.83-57.73+). Two patients died during study because of disease progression. Overall, the chemotherapy combined with Sr-89 was well tolerated. CONCLUSIONS: Our results demonstrate that the combination of alternating weekly chemohormonal therapies with Sr-89 demonstrates a prolonged progression-free and overall survival with acceptable toxicity. Further investigation of combination therapies with Sr-89 is warranted.