Early Changes in Circulating Cell-Free KRAS G12C Predict Response to Adagrasib in KRAS Mutant Non-Small Cell Lung Cancer Patients

PURPOSE

Non-invasive monitoring of circulating tumor DNA (ctDNA) has the potential to be a readily available measure for early prediction of clinical response. Here, we report on early ctDNA changes of KRAS G12C in a Phase 2 trial of adagrasib in patients with advanced, KRAS G12C-mutant lung cancer.

EXPERIMENTAL DESIGN

We performed serial droplet digital PCR (ddPCR) and plasma NGS on 60 KRAS G12C-mutant patients with lung cancer that participated in cohort A of the KRYSTAL-1 clinical trial. We analyzed the change in ctDNA at 2 specific intervals: Between cycles 1 and 2 and at cycle 4. Changes in ctDNA were compared with clinical and radiographic response.

RESULTS

We found that, in general, a maximal response in KRAS G12C ctDNA levels could be observed during the initial approximately 3-week treatment period, well before the first scan at approximately 6 weeks. 35 patients (89.7%) exhibited a decrease in KRAS G12C cfDNA >90% and 33 patients (84.6%) achieved complete clearance by cycle 2. Patients with complete ctDNA clearance at cycle 2 showed an improved objective response rate (ORR) compared with patients with incomplete ctDNA clearance (60.6% vs. 33.3%). Furthermore, complete ctDNA clearance at cycle 4 was associated with an improved overall survival (14.7 vs. 5.4 months) and progression-free survival (HR, 0.3).

CONCLUSIONS

These results support using early plasma response of KRAS G12C assessed at approximately 3 weeks to anticipate the likelihood of a favorable objective clinical response.

Adagrasib in Non-Small-Cell Lung Cancer Harboring a KRASG12C Mutation

BACKGROUND

Adagrasib, a KRAS^G12C inhibitor, irreversibly and selectively binds KRAS^G12C, locking it in its inactive state. Adagrasib showed clinical activity and had an acceptable adverse-event profile in the phase 1-1b part of the KRYSTAL-1 phase 1-2 study.

METHODS

In a registrational phase 2 cohort, we evaluated adagrasib (600 mg orally twice daily) in patients with KRAS^G12C -mutated non-small-cell lung cancer (NSCLC) previously treated with platinum-based chemotherapy and anti-programmed death 1 or programmed death ligand 1 therapy. The primary end point was objective response assessed by blinded independent central review. Secondary end points included the duration of response, progression-free survival, overall survival, and safety.

RESULTS

As of October 15, 2021, a total of 116 patients with KRAS^G12C -mutated NSCLC had been treated (median follow-up, 12.9 months); 98.3% had previously received both chemotherapy and immunotherapy. Of 112 patients with measurable disease at baseline, 48 (42.9%) had a confirmed objective response. The median duration of response was 8.5 months (95% confidence interval [CI], 6.2 to 13.8), and the median progression-free survival was 6.5 months (95% CI, 4.7 to 8.4). As of January 15, 2022 (median follow-up, 15.6 months), the median overall survival was 12.6 months (95% CI, 9.2 to 19.2). Among 33 patients with previously treated, stable central nervous system metastases, the intracranial confirmed objective response rate was 33.3% (95% CI, 18.0 to 51.8). Treatment-related adverse events occurred in 97.4% of the patients - grade 1 or 2 in 52.6% and grade 3 or higher in 44.8% (including two grade 5 events) - and resulted in drug discontinuation in 6.9% of patients.

CONCLUSIONS

In patients with previously treated KRAS^G12C -mutated NSCLC, adagrasib showed clinical efficacy without new safety signals. (Funded by Mirati Therapeutics; ClinicalTrials.gov number, NCT03785249.).

KRYSTAL-1: Activity and safety of adagrasib (MRTX849) in patients with advanced/metastatic non–small cell lung cancer (NSCLC) harboring a KRASG12C mutation

9002

Background: KRAS is a key mediator of the RAS/MAPK signaling cascade that promotes cellular growth and proliferation. KRASG12C mutation occurs in ̃14% of NSCLC. Adagrasib, an investigational agent, is a KRASG12C inhibitor that irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib is optimized for favorable pharmacokinetic (PK) properties, including long half-life (̃24 h), dose-dependent PK, and central nervous system penetration; it has demonstrated objective response and favorable tolerability in the Phase 1/1b setting. Methods: KRYSTAL-1 (NCT03785249) is a multicohort Phase 1/2 study evaluating adagrasib as monotherapy or in combination regimens in patients with advanced solid tumors harboring a KRASG12C mutation. Here we report the first disclosure from all patients enrolled in Cohort A, a Phase 2 cohort with registrational intent, evaluating adagrasib given 600 mg orally BID in patients with NSCLC previously treated with platinum-based chemotherapy and anti-PD-1/L1 therapy. Study objectives include evaluating efficacy (objective response rate [ORR], duration of response [DOR], progression-free survival [PFS], overall survival [OS]), safety, PK, and exploratory correlative analyses. Objective tumor response was assessed per RECIST v1.1 by blinded independent central review (BICR). Results: As of the 15 October 2021 data cutoff, 116 patients with NSCLC harboring a KRASG12C mutation were enrolled and treated, with a median follow-up of 12.5 months. Baseline characteristics include median age 64 years, 65% female, and 15.5%/83.6% with ECOG PS 0/1; 98.3% of patients received adagrasib following prior treatment with immunotherapy and chemotherapy, with a median of 2 prior systemic therapies. The ORR (by BICR) was 42.9% (48/112) and the disease control rate was 79.5% (89/112); 31 patients remain on treatment. Median DOR was 8.5 months (95% CI 6.2–13.8), median PFS was 6.5 months (95% CI 4.7–8.4), median OS was 12.6 months (95% CI 9.2–NE). Treatment-related AEs (TRAEs) of any grade occurred in 97.4% of patients, grade ≥3 TRAEs in 45.7%, 2 grade 5 TRAEs, and 8 (6.9%) TRAEs led to discontinuation. The most commonly reported (≥25%) TRAEs (any grade) were diarrhea (62.9%), nausea (62.1%), vomiting (47.4%), fatigue (40.5%), ALT/AST increased (27.6%/25%), blood creatinine increased (25.9%); the most commonly reported (≥5%) TRAEs (grade 3/4) were lipase increased (6%) and anemia (5.2%). Additional subgroup analyses will be presented, including selected demographics, molecular markers and sites of metastases. Conclusions: Adagrasib is well tolerated and demonstrates promising efficacy in pretreated patients with NSCLC harboring a KRASG12C mutation. A Phase 3 trial evaluating adagrasib monotherapy versus docetaxel in previously treated patients with KRASG12C-mutant NSCLC is ongoing (NCT04685135). Clinical trial information: NCT03785249.

First-in-Human Phase I/IB Dose-Finding Study of Adagrasib (MRTX849) in Patients With Advanced KRASG12C Solid Tumors (KRYSTAL-1)

Adagrasib (MRTX849) is an oral, highly selective, small-molecule, covalent inhibitor of KRAS^G12C. We report results from a phase I/IB study of adagrasib in non–small-cell lung cancer, colorectal cancer, and other solid tumors harboring the KRAS^G12C mutation.

KRYSTAL-12: A randomized phase 3 study of adagrasib (MRTX849) versus docetaxel in patients (pts) with previously treated non-small-cell lung cancer (NSCLC) with KRASG12C mutation

TPS9129

Background: Despite significant advances in chemotherapy and immunotherapy for advanced NSCLC, the majority of pts ultimately develop progressive disease associated with poor outcomes. KRAS is a key mediator of the RAS/MAPK signaling cascade that promotes cell growth and proliferation. KRASG12C mutations occur in 14% of NSCLC (adenocarcinoma), and mutations in KRAS are associated with a poor prognosis. Although KRAS has historically been undruggable, recent research into the development of agents that specifically bind mutant KRAS has led to the development of direct inhibitors of KRASG12C. Adagrasib, an investigational agent, is a potent, covalent inhibitor of KRASG12C that irreversibly and selectively binds to and locks KRASG12C in its inactive state. Adagrasib was optimized for favorable pharmacokinetic (PK) properties, including oral bioavailability, long half-life (̃24 h), and extensive tissue distribution. Initial results have demonstrated encouraging antitumor activity and tolerability of adagrasib monotherapy in pts with NSCLC harboring a KRASG12C mutation. Methods: KRYSTAL-12 is a multicenter, randomized Phase 3 study evaluating the efficacy of adagrasib (600 mg BID) vs docetaxel in pts with advanced NSCLC harboring a KRASG12C mutation who have progressed during or after treatment with a platinum-based regimen and an immune checkpoint inhibitor. The study is designed to demonstrate improvement in the dual primary endpoints of progression-free survival (PFS) and overall survival (OS). Secondary endpoints include safety, objective response rate (ORR) per RECIST 1.1, duration of response (DOR), plasma PK parameters of adagrasib, and patient-reported outcomes (PROs). The study will also explore correlations between gene alterations (at baseline and upon development of treatment resistance) and efficacy. Approximately 450 patients will be randomized in a 2:1 ratio to receive adagrasib or docetaxel and will be stratified by region (United States/Canada vs other countries) and sequential vs concurrent administration of prior platinum-based chemotherapy and anti–PD-1/PD-L1 antibody. The planned sample size is sufficiently powered for the hypothesized treatment effect of the endpoints. Pts will receive study treatment until disease progression, unacceptable adverse events, investigator decision to terminate treatment, or patient withdrawal. This study is currently enrolling and will be open at sites in the United States, Europe, and Asia. Clinical trial information: NCT04685135.

The KRASG12C Inhibitor MRTX849 Provides Insight toward Therapeutic Susceptibility of KRAS-Mutant Cancers in Mouse Models and Patients

Despite decades of research, efforts to directly target KRAS have been challenging. MRTX849 was identified as a potent, selective, and covalent KRAS^G12C inhibitor that exhibits favorable drug-like properties, selectively modifies mutant cysteine 12 in GDP-bound KRAS^G12C, and inhibits KRAS-dependent signaling. MRTX849 demonstrated pronounced tumor regression in 17 of 26 (65%) KRAS^G12C-positive cell line- and patient-derived xenograft models from multiple tumor types, and objective responses have been observed in patients with KRAS^G12C-positive lung and colon adenocarcinomas. Comprehensive pharmacodynamic and pharmacogenomic profiling in sensitive and partially resistant nonclinical models identified mechanisms implicated in limiting antitumor activity including KRAS nucleotide cycling and pathways that induce feedback reactivation and/or bypass KRAS dependence. These factors included activation of receptor tyrosine kinases (RTK), bypass of KRAS dependence, and genetic dysregulation of cell cycle. Combinations of MRTX849 with agents that target RTKs, mTOR, or cell cycle demonstrated enhanced response and marked tumor regression in several tumor models, including MRTX849-refractory models. SIGNIFICANCE: The discovery of MRTX849 provides a long-awaited opportunity to selectively target KRAS^G12C in patients. The in-depth characterization of MRTX849 activity, elucidation of response and resistance mechanisms, and identification of effective combinations provide new insight toward KRAS dependence and the rational development of this class of agents.See related commentary by Klempner and Hata, p. 20.This article is highlighted in the In This Issue feature, p. 1.

A phase I/II multiple expansion cohort trial of MRTX849 in patients with advanced solid tumors with KRAS G12C mutation

TPS3161

Background: RAS proteins are part of the family of small GTPases which regulate intracellular signaling pathways responsible for cell growth, migration, survival and differentiation. Oncogenic point mutations in RAS in codons 12, 13, and 61 occur in up to one-third of all human cancers and result in constitutive activation of RAS signaling, playing a key role in uncontrolled cellular growth and malignant transformation. Mutant KRASG12C in particular comprises approximately 14% of lung adenocarcinoma and 4% of colon adenocarcinoma, and less commonly in certain other types of cancer. For decades, KRAS was considered undruggable due to its high affinity for GTP/GDP and the lack of a clear binding pocket. Recent discoveries have enabled the development of compounds, including MRTX849, that covalently bind to KRASG12C at the cysteine at residue 12, lock the protein in its inactive GDP-bound conformation, and inhibit KRAS-dependent signal transduction. MRTX849 is a potent, orally-available, mutation-selective small molecule covalent inhibitor of KRASG12C. MRTX849 inhibits KRASG12C signaling in cell lines harboring this mutation, and results in tumor regression in a broad spectrum of KRASG12C animal models. Methods: This multi-center, Phase 1/2, multiple expansion cohort trial evaluates the safety, pharmacokinetics (PK), metabolites, pharmacodynamics, and clinical activity of MRTX849 in patients with advanced solid tumor malignancies with a KRAS (p.G12C) mutation. The study starts with an evaluation of dose and regimen of MRTX849 using a combination of the accelerated titration and modified toxicity probability interval designs, with MRTX849 initially administered once daily in a continuous regimen expressed in 3-week cycles. As potentially viable regimens are identified, Phase 1b expansion cohorts will be opened to provide greater safety and PK data for determination of the recommended Phase 2 dose (RP2D) and regimen. In Phase 2, separate cohorts of patients by histological diagnosis, including non-small cell lung cancer, colorectal, and other solid tumors, will be enrolled and evaluated for clinical activity using a predictive probability design. The study is open for enrollment, and recruitment is ongoing. Clinical trial information: NCT03785249.

Correction to: Phase II study of sunitinib in Japanese patients with unresectable or metastatic, well-differentiated pancreatic neuroendocrine tumor

In the original publication of this article, the license subtype should be CC BY and not CC BY-NC.

Mocetinostat for patients with previously treated, locally advanced/metastatic urothelial carcinoma and inactivating alterations of acetyltransferase genes

Background

The authors evaluated mocetinostat (a class I/IV histone deacetylase inhibitor) in patients with urothelial carcinoma harboring inactivating mutations or deletions in CREB binding protein [CREBBP] and/or E1A binding protein p300 [EP300] histone acetyltransferase genes in a single‐arm, open‐label phase 2 study.

Methods

Eligible patients with platinum‐treated, advanced/metastatic disease received oral mocetinostat (at a dose of 70 mg 3 times per week [TIW] escalating to 90 mg TIW) in 28‐day cycles in a 3‐stage study (ClinicalTrials.gov identifier NCT02236195). The primary endpoint was the objective response rate.

Results

Genomic testing was feasible in 155 of 175 patients (89%). Qualifying tumor mutations were CREBBP (15%), EP300 (8%), and both CREBBP and EP300 (1%). A total of 17 patients were enrolled into stage 1 (the intent‐to‐treat population); no patients were enrolled in subsequent stages. One partial response was observed (11% [1 of 9 patients; the population that was evaluable for efficacy comprised 9 of the 15 planned patients]); activity was deemed insufficient to progress to stage 2 (null hypothesis: objective response rate of ≤15%). All patients experienced ≥1 adverse event, most commonly nausea (13 of 17 patients; 77%) and fatigue (12 of 17 patients; 71%). The median duration of treatment was 46 days; treatment interruptions (14 of 17 patients; 82%) and dose reductions (5 of 17 patients; 29%) were common. Mocetinostat exposure was lower than anticipated (dose‐normalized maximum serum concentration [C_max] after TIW dosing of 0.2 ng/mL/mg).

Conclusions

To the authors’ knowledge, the current study represents the first clinical trial using genomic‐based selection to identify patients with urothelial cancer who are likely to benefit from selective histone deacetylase inhibition. Mocetinostat was associated with significant toxicities that impacted drug exposure and may have contributed to modest clinical activity in these pretreated patients. The efficacy observed was considered insufficient to warrant further investigation of mocetinostat as a single agent in this setting.

After the genomic‐based selection of patients with urothelial cancer with inactivating mutations/deletions in the histone acetyltransferase genes CREBBP and/or EP300, single‐agent mocetinostat appears to be associated with significant toxicities that limit drug exposure. This may have contributed to the limited activity noted in the current phase 2 study (response rate of 11%) among heavily pretreated patients with platinum‐refractory disease.

A randomized, double-blind, phase II study of erlotinib with or without sunitinib for the second-line treatment of metastatic non-small-cell lung cancer (NSCLC)

BACKGROUND

Combined inhibition of vascular, platelet-derived, and epidermal growth factor receptor (EGFR) pathways may overcome refractoriness to single agents in platinum-pretreated non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

This randomized, double-blind, multicenter, phase II trial evaluated sunitinib 37.5 mg/day plus erlotinib 150 mg/day versus placebo plus erlotinib continuously in 4-week cycles. Eligible patients had histologically confirmed stage IIIB or IV NSCLC previously treated with one or two chemotherapy regimens, including one platinum-based regimen. The primary end point was progression-free survival (PFS) by an independent central review.

RESULTS

One hundred and thirty-two patients were randomly assigned, and the median duration of follow-up was 17.7 months. The median PFS was 2.8 versus 2.0 months for the combination versus erlotinib alone (HR 0.898, P = 0.321). The median overall survival (OS) was 8.2 versus 7.6 months (HR 1.066, P = 0.617). Objective response rates (ORRs) were 4.6% and 3.0%, respectively. Sunitinib plus erlotinib was fairly well tolerated although most treatment-related adverse events (AEs) were more frequent than with erlotinib alone: diarrhea (55% versus 33%), rash (41% versus 30%), fatigue (31% versus 25%), decreased appetite (30% versus 13%), nausea (28% versus 14%), and thrombocytopenia (13% versus 0%).

CONCLUSIONS

The addition of sunitinib to erlotinib did not significantly improve PFS in patients with advanced, platinum-pretreated NSCLC.

Phase II study of sunitinib in Japanese patients with unresectable or metastatic, well-differentiated pancreatic neuroendocrine tumor

Background. Pancreatic neuroendocrine tumors (NETs) are rare but are frequently diagnosed at advanced stages and require systemic therapy. Patients and methods. This multicenter, open-label, phase II study evaluated sunitinib in Japanese patients with well-differentiated pancreatic NET. Patients received sunitinib 37.5 mg/day on a continuous daily dosing (CDD) schedule. The primary endpoint was clinical benefit rate (CBR; percentage of complete responses [CRs] plus partial responses [PRs] plus stable disease [SD] ≥24 weeks). Secondary endpoints included objective response rate (ORR), tumor shrinkage, progression-free survival (PFS) probability, safety, pharmacokinetics, and biomarkers. Results. Twelve patients received treatment. The CBR was 75 % (95 % confidence interval [CI], 43–94) and included 6 patients with a PR and 3 with SD. The ORR was 50 % (95 % CI, 21–79). PFS probability was 91 % (95 % CI, 54–99) at 6 months and 71 % (95 % CI, 34–90) at 12 months. Commonly reported treatment-emergent (all-causality), any-grade adverse events included diarrhea (n = 10), hand–foot syndrome and hypertension (both n = 8), fatigue and headache (both n = 7), and neutropenia (n = 6). No deaths on study were reported; one death due to disease progression occurred >28 days after end of treatment. Sunitinib on a CDD schedule resulted in sustained drug concentrations without accumulation across cycles. Tumor responses in all 12 patients did not appear to correlate with decreases in chromogranin A levels. Conclusions. Sunitinib 37.5 mg/day on a CDD schedule demonstrated antitumor activity in Japanese patients with unresectable, well-differentiated pancreatic NET. Commonly reported adverse events were consistent with the known safety profile of sunitinib.

Updated results from a phase III trial of sunitinib versus placebo in patients with progressive, unresectable, well-differentiated pancreatic neuroendocrine tumor (NET)

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Background: In a double-blind phase III trial, sunitinib (Sutent; SU) improved progression-free survival (PFS) vs placebo (PBO; 11.4 vs 5.5 mos; HR: 0.42, 95% CI: 0.26–0.66; P=0.0001) and was well tolerated in patients (pts) with unresectable, well-differentiated pancreatic NET that had progressed ≤12 mos before baseline. Initial overall survival (OS) revealed a benefit for SU vs PBO, although median OS had not been reached. We now report PFS assessed by blinded independent central review (BICR) and updated OS. Methods: Pts were randomized 1:1 to SU 37.5 mg or PBO on a continuous daily dosing schedule, each with best supportive care. The primary endpoint was investigator-assessed PFS; OS was a secondary endpoint to be evaluated every 2 yrs for 5 yrs, or until 95% of pts had died. Additionally, BICR was performed retrospectively; baseline and on-study CT/MRI scans were evaluated by a 2-reader, 2-time-point lock, followed by a sequential locked-read, batch-mode paradigm by blinded, third-party radiologists. Results: 171 pts were randomized (SU, n=86; PBO, n=85) from Jun 2007 to Apr 2009. The trial ended when an independent data monitoring committee noted efficacy favoring SU and more serious AEs and deaths with PBO. The study was unblinded at closure; pts were offered open-label SU and followed for survival. Median PFS by BICR was 12.6 mos (SU) vs 5.8 mos (PBO) (HR: 0.32, 95% CI: 0.18–0.55; P=0.00001). At study closure, there were 9 and 21 deaths in the SU and PBO arms (HR: 0.41, 95% CI: 0.19–0.89; P=0.02). By Apr 2011 (2 yrs additional follow-up) a total of 87 deaths occurred (51%), median OS was estimated at 33.0 mos in the SU arm, and 26.7 mos in the PBO arm (HR: 0.71, 95% CI: 0.47–1.09; P=0.11 [Table]). 69% of pts crossed over to SU on progression. Conclusions: BICR confirmed investigator assessment of PFS and demonstrated a 6.8-mo improvement in median PFS with SU. Updated OS favors SU, although this result is non-significant for reasons that may include crossover of treatment and limited statistical power. [Table: see text]

Sunitinib plus erlotinib versus placebo plus erlotinib in patients with previously treated advanced non-small-cell lung cancer: a phase III trial

PURPOSE

Sunitinib plus erlotinib may enhance antitumor activity compared with either agent alone in non-small-cell lung cancer (NSCLC), based on the importance of the signaling pathways involved in tumor growth, angiogenesis, and metastasis. This phase III trial investigated overall survival (OS) for sunitinib plus erlotinib versus placebo plus erlotinib in patients with refractory NSCLC.

PATIENTS AND METHODS

Patients previously treated with one to two chemotherapy regimens (including one platinum-based regimen) for recurrent NSCLC, and for whom erlotinib was indicated, were randomly assigned (1:1) to sunitinib 37.5 mg/d plus erlotinib 150 mg/d or to placebo plus erlotinib 150 mg/d, stratified by prior bevacizumab use, smoking history, and epidermal growth factor receptor expression. The primary end point was OS. Key secondary end points included progression-free survival (PFS), objective response rate (ORR), and safety.

RESULTS

In all, 960 patients were randomly assigned, and baseline characteristics were balanced. Median OS was 9.0 months for sunitinib plus erlotinib versus 8.5 months for erlotinib alone (hazard ratio [HR], 0.922; 95% CI, 0.797 to 1.067; one-sided stratified log-rank P = .1388). Median PFS was 3.6 months versus 2.0 months (HR, 0.807; 95% CI, 0.695 to 0.937; one-sided stratified log-rank P = .0023), and ORR was 10.6% versus 6.9% (two-sided stratified log-rank P = .0471), respectively. Treatment-related toxicities of grade 3 or higher, including rash/dermatitis, diarrhea, and asthenia/fatigue were more frequent in the sunitinib plus erlotinib arm.

CONCLUSION

In patients with refractory NSCLC, sunitinib plus erlotinib did not improve OS compared with erlotinib alone, but the combination was associated with a statistically significantly longer PFS and greater ORR. The incidence of grade 3 or higher toxicities was greater with combination therapy.

A phase I dose-escalation and pharmacokinetic study of sunitinib in combination with pemetrexed in patients with advanced solid malignancies, with an expanded cohort in non-small cell lung cancer

Purpose

The primary objective of this phase I dose-escalation study was to identify the maximum tolerated dose (MTD) of sunitinib plus pemetrexed in patients with advanced cancer.

Methods

Using a 3 + 3 dose-escalation design, patients received oral sunitinib qd by continuous daily dosing (CDD schedule; 37.5 or 50 mg) or 2 weeks on/1 week off treatment schedule (Schedule 2/1; 50 mg). Pemetrexed (300–500 mg/m² IV) was administered q3w. At the proposed recommended phase 2 dose (RP2D), additional patients with non-small cell lung cancer (NSCLC) were enrolled.

Results

Thirty-five patients were enrolled on the CDD schedule and seven on Schedule 2/1. MTDs were sunitinib 37.5 mg/day (CDD/RP2D) or 50 mg/day (Schedule 2/1) with pemetrexed 500 mg/m². Dose-limiting toxicities included grade (G) 5 cerebral hemorrhage, G3 febrile neutropenia, and G3 anorexia. Common G3/4 drug-related non-hematologic adverse events (AEs) at the CDD MTD included fatigue, anorexia, and hand–foot syndrome. G3/4 hematologic AEs included lymphopenia, neutropenia, and thrombocytopenia. No significant drug–drug interactions were identified. Five (24%) NSCLC patients had partial responses.

Conclusions

In patients with advanced solid malignancies, the MTD of sunitinib plus 500 mg/m² pemetrexed was 37.5 mg/day (CDD schedule) or 50 mg/day (Schedule 2/1). The CDD schedule MTD was tolerable and demonstrated promising clinical benefit in NSCLC.

Sunitinib in combination with paclitaxel plus carboplatin in patients with advanced solid tumors: phase I study results

PURPOSE

To evaluate the maximum tolerated dose (MTD), safety, and antitumor activity of sunitinib combined with paclitaxel and carboplatin.

METHODS

Successive cohorts of patients with advanced solid tumors received oral sunitinib (25, 37.5, or 50 mg) for 2 consecutive weeks of a 3-week cycle (Schedule 2/1) or as a continuous daily dose for 3-week cycles (CDD schedule) in combination with paclitaxel (175-200 mg/m(2)) plus carboplatin (AUC 6 mg min/ml) on day one of each of 4 cycles. Dose-limiting toxicities (DLTs) and adverse events (AEs) were evaluated to determine the MTD. Efficacy parameters were analyzed in patients with measurable disease.

RESULTS

Forty-three patients were enrolled (n = 25 Schedule 2/1; n = 18 CDD schedule). Across all doses, 6 DLTs were observed [grade 4 papilledema, grade 5 GI hemorrhage, grade 3 neutropenic infection, and grade 4 thrombocytopenia (n = 3)]. The MTD for Schedule 2/1 was sunitinib 25 mg plus paclitaxel 175 mg/m(2) and carboplatin AUC 6 mg min/ml. The MTD was not determined for the CDD schedule. Treatment-related AEs included neutropenia (77%), thrombocytopenia (56%), and fatigue (47%). Of 38 evaluable patients, 4 (11%) had partial responses and 12 (32%) had stable disease. PK data indicated an increase in maximum and total plasma exposures to sunitinib and its active metabolite when given with paclitaxel and carboplatin compared with sunitinib monotherapy.

CONCLUSIONS

Myelosuppression resulting in prolonged dose delays and frequent interruptions was observed, suggesting that this treatment combination is not feasible in the general cancer population.

Multicenter, phase II trial of sunitinib in previously treated, advanced non-small-cell lung cancer

PURPOSE

Aberrant vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) signaling have been shown to play a role in non-small-cell lung cancer (NSCLC) pathogenesis and are associated with decreased survival. We evaluated the clinical activity and tolerability of sunitinib malate (SU11248), an oral, multitargeted tyrosine kinase inhibitor that blocks the activity of receptors for VEGF and PDGF, as well as related tyrosine kinases in patients with previously treated, advanced NSCLC.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC for whom platinum-based chemotherapy had failed received 50 mg/d of sunitinib for 4 weeks followed by 2 weeks of no treatment in 6-week treatment cycles. The primary end point was objective response rate (ORR); secondary end points included progression-free survival, overall survival, and safety.

RESULTS

Of the 63 patients treated with sunitinib, seven patients had confirmed partial responses, yielding an ORR of 11.1% (95% CI, 4.6% to 21.6%). An additional 18 patients (28.6%) experienced stable disease of at least 8 weeks in duration. Median progression-free survival was 12.0 weeks (95% CI, 10.0 to 16.1 weeks), and median overall survival was 23.4 weeks (95% CI, 17.0 to 28.3 weeks). Therapy was generally well tolerated.

CONCLUSION

Sunitinib has promising single-agent activity in patients with recurrent NSCLC, with an ORR similar to that of currently approved agents and an acceptable safety profile. Further evaluation in combination with other targeted agents and chemotherapy in patients with NSCLC is warranted.

Phase II trial of sunitinib in patients with metastatic colorectal cancer after failure of standard therapy

PURPOSE

Sunitinib is an oral, multitargeted receptor tyrosine kinase inhibitor of the vascular endothelial growth factor receptor and multiple other growth factor receptors. We assessed the safety and efficacy of sunitinib in patients with metastatic colorectal cancer after failure of standard therapy.

PATIENTS AND METHODS

Eighty-four patients were enrolled onto this two-stage phase II trial and were stratified by whether they had received prior bevacizumab (n = 43) or not (n = 41). Treatment comprised sunitinib 50 mg orally daily for 4 weeks, followed by 2 weeks off treatment, in repeated 6-week cycles.

RESULTS

By Response Evaluation Criteria in Solid Tumors criteria, one patient, who was in the prior bevacizumab cohort, achieved a partial response, and 13 patients (two in the prior bevacizumab cohort and 11 in the no prior bevacizumab cohort) achieved stable disease lasting > or = 22 weeks. Median time to progression in the prior bevacizumab and bevacizumab-naïve cohorts was 2.2 months (95% CI, 1.9 to 2.3 months) and 2.5 months (95% CI, 2.3 to 3.1 months), respectively, whereas median overall survival time was 7.1 months (95% CI, 4.9 to 10.6 months) and 10.2 months (95% CI, 8.2 to 15.3 months), respectively. The most common adverse events were fatigue, diarrhea, nausea, vomiting, and anorexia. Twenty-six patients (32%) required dose reduction to 37.5 mg/d, and one patient required dose reduction to 25 mg/d.

CONCLUSION

Sunitinib did not demonstrate a meaningful single-agent objective response rate in colorectal cancer refractory to standard chemotherapy. However, the mechanisms of action and acceptable safety profile of sunitinib warrant further study in combination with standard regimens for metastatic colorectal cancer.

Therapy-induced malignant neoplasms in Nf1 mutant mice

Therapy-induced cancers are a severe complication of genotoxic therapies. We used heterozygous Nf1 mutant mice as a sensitized genetic background to investigate tumor induction by radiation (RAD) and cyclophosphamide (CY). Mutagen-exposed Nf1(+/-) mice developed secondary cancers that are common in humans, including myeloid malignancies, sarcomas, and breast cancers. RAD cooperated strongly with heterozygous Nf1 inactivation in tumorigenesis. Most of the solid tumors showed loss of the wild-type Nf1 allele but retained two Trp53 alleles. Comparative genomic hybridization demonstrated distinct patterns of copy number aberrations in sarcomas and breast cancers from Nf1 mutant mice, and tumor cell lines showed deregulated Ras signaling. Nf1(+/-) mice provide a tractable model for investigating the pathogenesis of common mutagen-induced cancers and for testing preventive strategies.

Comparative pathology of nerve sheath tumors in mouse models and humans

Despite the progress made in our understanding of the biology of neurofibromatosis (NF), the long-term clinical outcome for affected patients has not changed significantly in the past decades, and both NF1 and NF2 are still associated with a significant morbidity and a decreased life span. A number of NF1 and NF2 murine models have been generated to aid in the study of NF tumor biology and in the development of targeted therapies for NF patients. A single, universal pathological classification of the lesions generated in these murine models is essential for the validation of the models, for their analysis and comparison with other models, and for their future effective use in preclinical treatment trials. For the formulation of a pathological classification of these lesions, the WHO classification of human tumors was used as a reference. However, it was not adopted for the classification of the GEM lesions because of some important differences between the human and murine lesions. A novel classification scheme for peripheral nerve sheath tumors in murine models was therefore devised.

Doppler echocardiographic diagnosis of intrauterine closure of the ductus arteriosus

A case of in utero closure of the ductus arteriosus was detected by Doppler echocardiography at 31 weeks of gestation. It presented as a non-hydropic distressed fetus with ultrasound detection of tricuspid regurgitation. Pulsed Doppler ultrasound showed markedly decreased blood flow through the tricuspid and pulmonary valves and absent blood flow at the ductus arteriosus. These, as well as the resultant increased right-to-left shunting across the foramen ovale, were reaffirmed by colour flow mapping.