Validity Assessment of an Automated Brain Morphometry Tool for Patients with De Novo Memory Symptoms

BACKGROUND AND PURPOSE

Automated volumetric analysis of structural MR imaging allows quantitative assessment of brain atrophy in neurodegenerative disorders. We compared the brain segmentation performance of the AI-Rad Companion brain MR imaging software against an in-house FreeSurfer 7.1.1/Individual Longitudinal Participant pipeline.

MATERIALS AND METHODS

T1-weighted images of 45 participants with de novo memory symptoms were selected from the OASIS-4 database and analyzed through the AI-Rad Companion brain MR imaging tool and the FreeSurfer 7.1.1/Individual Longitudinal Participant pipeline. Correlation, agreement, and consistency between the 2 tools were compared among the absolute, normalized, and standardized volumes. Final reports generated by each tool were used to compare the rates of detection of abnormality and the compatibility of radiologic impressions made using each tool, compared with the clinical diagnoses.

RESULTS

We observed strong correlation, moderate consistency, and poor agreement between absolute volumes of the main cortical lobes and subcortical structures measured by the AI-Rad Companion brain MR imaging tool compared with FreeSurfer. The strength of the correlations increased after normalizing the measurements to the total intracranial volume. Standardized measurements differed significantly between the 2 tools, likely owing to differences in the normative data sets used to calibrate each tool. When considering the FreeSurfer 7.1.1/Individual Longitudinal Participant pipeline as a reference standard, the AI-Rad Companion brain MR imaging tool had a specificity of 90.6%-100% and a sensitivity of 64.3%-100% in detecting volumetric abnormalities. There was no difference between the rate of compatibility of radiologic and clinical impressions when using the 2 tools.

CONCLUSIONS

The AI-Rad Companion brain MR imaging tool reliably detects atrophy in cortical and subcortical regions implicated in the differential diagnosis of dementia.

Antitumor activity and safety of pembrolizumab in patients with advanced recurrent ovarian cancer: results from the phase II KEYNOTE-100 study

BACKGROUND

Advanced recurrent ovarian cancer (ROC) is the leading cause of gynecologic cancer-related death in developed countries and new treatments are needed. Previous studies of immune checkpoint blockade showed low objective response rates (ORR) in ROC with no identified predictive biomarker.

PATIENTS AND METHODS

This phase II study of pembrolizumab (NCT02674061) examined two patient cohorts with ROC: cohort A received one to three prior lines of treatment with a platinum-free interval (PFI) or treatment-free interval (TFI) between 3 and 12 months and cohort B received four to six prior lines with a PFI/TFI of ≥3 months. Pembrolizumab 200 mg was administered intravenously every 3 weeks until cancer progression, toxicity, or completion of 2 years. Primary end points were ORR by Response Evaluation Criteria in Solid Tumors version 1.1 per blinded independent central review by cohort and by PD-L1 expression measured as combined positive score (CPS). Secondary end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Cohort A enrolled 285 patients; the first 100 served as the training set for PD-L1 biomarker analysis. Cohort B enrolled 91 patients. ORR was 7.4% for cohort A and 9.9% for cohort B. Median DOR was 8.2 months for cohort A and not reached for cohort B. DCR was 37.2% and 37.4%, respectively, in cohorts A and B. Based on the training set analysis, CPS 1 and 10 were selected for evaluation in the confirmation set. In the confirmation set, ORR was 4.1% for CPS <1, 5.7% CPS ≥1, and 10.0% for CPS ≥10. PFS was 2.1 months for both cohorts. Median OS was not reached for cohort A and was 17.6 months for cohort B. Toxicities were consistent with other single-agent pembrolizumab trials.

CONCLUSIONS

Single-agent pembrolizumab showed modest activity in patients with ROC. Higher PD-L1 expression was correlated with higher response.

CLINICAL TRIAL NUMBER

Clinicaltrials.gov, NCT02674061.

Abstract P2-16-20: Biomarkers to predict response to the CDK 4/6 inhibitor, palbociclib (PD 0332991) in a single-agent phase II trial in advanced breast cancer

Background: The Cyclin D1-CDK4/6 complex is critical in regulating the G1/S checkpoint and phosphorylation of retinoblastoma protein (Rb); palbociclib is a highly-selective CDK 4/6 inhibitor. CCND1, the gene encoding Cyclin D1, is amplified in 15% of breast tumors; p16, the endogenous inhibitor of the complex is lost in up to half of breast tumors. We hypothesized that breast tumors containing either alteration or a high proliferative rate would have enhanced sensitivity to palbociclib. We conducted a single-agent, phase II trial of palbociclib in patients with advanced breast cancer (UPCC03909). In this trial, the clinical benefit rate (partial response [PR] + stable disease ≥6 months [6mSD]) was 17% (DeMichele, ASCO, 2013). The current analysis was a secondary endpoint to determine whether Rb expression, p16 loss, Ki-67 index or CCND1 amplification predicted response in the phase II trial.

Methods: Enrollment on UPCC03909 required archival tumor collection from either primary tumor or metastatic lesions. Fresh frozen paraffin-embedded (FFPE) tumor sections were tested for expression of Rb, Ki-67 and p16 by immunohistochemistry (IHC), and CCND1 amplification by fluorescence in situ hybridization. Categorical variables based on% tumor staining and intensity scores (negative defined as 0 or 1+ intensity staining, equivocal defined as 2+ staining or 3+ in &lt;30%, or positive defined as 3+ staining intensity in 30%) were generated for Rb and p16 nuclear staining. Fisher's Exact test was used to test for associations between nominal factors, the Cochran-Mantel-Hænszel test for associations between ordinal factors, and the Cox proportional hazard model for association of progression-free survival (PFS) with biomarkers.

Results: Thirty-seven patients were enrolled; response evaluation is available in 36/37. All had FFPE tumor available for Rb, 33/37 (89%)for CCND1 amplification and 29/37 (78%) for Ki-67 and p16 analyses. For complete results see Table 1.

Conclusions: These results provide preliminary evidence that breast tumors more likely to respond to palbociclib may have higher Rb nuclear expression, lower Ki67 indices and/or loss of p16. Larger studies are needed to confirm these results.

Table 1: Biomarker Summary and ResponseBiomarkerBiomarker CategoizationFrequency (%)Response Rate PR+6mSD/total (%)PFS Hazard Ratio (95%CI)Overall Population (n = 37)  6/36 (17%) Ki-67 (n = 29)≤ 10 (n = 20)69%4/19 (21%)1.00 &gt; 10 (n = 9)31%1/9 (11%)1.20 (0.50, 2.88)Rb (n = 37)Nuclear Score: Negative (n = 11)30%0/11 (0%)1.00 Equivocal (n = 15)40%2/14 (14.3%)0.72 (0.28, 1.84) Positive (n = 11)30%4/11 (36.4%)0.71 (0.28, 1.80)p16 (n = 29)Loss or Low Expression (n = 16)55%4/16 (25%)1.00 Moderate or High Expression (n = 13)45%1/12 (8.3%)1.08 (0.47, 2.49)CCND1 Amplification (n = 34)Non-amplified (n = 25)88%4/25 (16%)1.00 Amplified (n = 9)12%1/8 (12.5%)1.06 (0.46, 2.4)

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-20.

P1-17-06: A Phase II Trial of the CDK 4/6 Inhibitor PD0332991 in Women with Advanced Breast Cancer

Background: Dysregulation of the G1/S checkpoint of the cell cycle is a feature of many breast cancers. PD0332991, a potent oral inhibitor of cyclin-dependent kinases (CDKs) 4 and 6 is well-tolerated and has demonstrated activity in a phase I trial in a variety of solid tumors at a phase II dose of 125 mg daily on a 3 week on/1 week off schedule. Preclinical data suggest that this agent is most active in ER+ (luminal) breast cancers. We are performing a phase II study of PD0332991 in women with advanced breast cancer, one of several parallel disease cohorts under study.

Methods: Patients with histologically-confirmed stage IV breast cancer were eligible if they had primary or metastatic tumor which stained positive for retinoblastoma (Rb) protein by immunohistochemistry, disease measureable by RECIST criteria and adequate organ function/performance status. Treatment was initiated with PD0332991 at 125 mg orally, days 1 - 21 of a 28-day treatment cycle. Tumor assessments occurred after every 2 cycles (8-week intervals). The primary objective was to determine the safety and response rates in cohorts of 15 patients per tumor type; 15 patients per arm provided 80% power to detect a 15% (1/15) response rate per disease that would lead to further cohort expansion. Secondary objectives include PK, PD and predictive biomarker assessment.

Results: 36 patients were screened, 32 (89%) stained positive for Rb, and 14 have enrolled on study. The only reported toxicites are neutropenia (7 patients, 4 grade 3/4), thrombocytopenia (1 patient, grade 1) and fatigue (1 patient, grade 2). 3 patients (23%) have had dose interruptions and 5 (38%) have had dose-reduction for neutropenia, though no episodes of febrile neutropenia have occurred. Among 11 patients assessable for response to date, there is 1(7%) partial response (PR), 6 (43%) with stable disease (SD) and 4 (29%) with progressive disease (PD). 3 of 6 patients with stable disease have received greater than 6 months of therapy, and these sustained responses have occurred with dosing as low as 50 mg/day. All PR/SD have occurred in patients with ER+ tumors; all PD have been in patients with triple negative (ER-/PR-/Her2-) disease. The cyclin D1 status of all patients are being assessed. Of the 10 ER+ patients, 3 are cyclin D1 amplified, 5 are non-amplified and 2 are pending assessment. 2 in 4 cyclin D1 non-amplified patients had SD, while 2 of 2 evaluable patients with amplification had SD. PK and PD analyses are in progress.

Conclusions: PD 0332991 is an extremely well-tolerated, oral CDK 4/6 inhibitor that demonstrates prolonged single-agent activity in ER+ breast cancer patients who have progressed on hormonal therapy. These data have prompted expansion of this breast cancer cohort to further delineate activity and translational studies examining predictors of response are underway.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-17-06.

Dosing patterns in patients with renal cell carcinoma treated with sorafenib or sunitinib: A retrospective claims database analysis

5097

Background: Tyrosine kinase inhibitors (TKIs; sorafenib [SR], sunitinib [SU]) are FDA approved for the treatment of advanced renal cell carcinoma (RCC). Dose reduction may be needed for management of treatment-related adverse events. We analyzed the dose reduction patterns in pts with RCC treated with SR, approved Dec 05, or SU, approved Jan 06. Methods: A retrospective analysis was conducted using data from a US claims-based database (MarketScan MedStat) covering ≥18 million lives for 2002–2008 in all US census regions. Inclusion criteria were ≥2 claims for RCC (ICD9 189.0 or 198.0), continuous healthcare coverage, >180 days of coverage before RCC diagnosis, no claim for SR or SU prior to RCC diagnosis, initial standard daily RCC dose per package insert recommendation (800 mg for SR or 50 mg for SU), and ≥2 consecutive dispensings. Initial episode was defined as the time from the date of the first drug dispensing (index date) to the first switch to another TKI, end of healthcare coverage, end of treatment, or March 31, 2008. Pt and pt-time level analyses for dose reductions between treatments were conducted. Results: SR- (n = 189) and SU-treated (n = 304) pts met the inclusion criteria. No significant differences in baseline demographics existed between the groups except for a higher incidence of stroke (7.9% vs 3.6%, p = 0.037) and other cancer site (93.7% vs 87.8%, p = 0.036) in the SR group. Significantly more pts who received SU (23%) required dose reductions during the first 3 months of therapy and for all initial episodes than did pts who received (4.2%) SR (p < 0.001 for both). For all episodes, the mean time to dose reduction was 104 days for SU versus 162 days with SR (p = 0.0028). The majority (65%) of dose reductions with SU occurred within the first 3 months, whereas dose reduction with SR was 25% during this time (p < 0.001). After controlling for different lengths of exposure time, 2 to 6 times more dose reductions were observed in pts who received SU than with SR (p < 0.001). Conclusions: This US retrospective claims analysis showed more dose reductions, including number of patients and total number of days, in pts who initially received sunitinib compared with those who received sorafenib.

[Table: see text]