Reducing off target viral delivery in ovarian cancer gene therapy using a protease-activated AAV2 vector platform

Gene therapy is a promising strategy for treating metastatic epithelial ovarian cancer (EOC). However, efficient vector targeting to tumors is difficult and off-target effects can be severely detrimental. Most vector targeting approaches rely on surface receptors overexpressed on some subpopulation of cancer cells. Unfortunately, there is no universally expressed cell surface biomarker for tumor cells. As an alternative, we developed an adeno-associated virus (AAV) based "Provector" whose cellular transduction can be activated by extracellular proteases, such as matrix metalloproteinases (MMP) that are overexpressed in the tumor microenvironments of the most aggressive forms of EOC. In a non-tumor bearing mouse model, the Provector demonstrates efficient de-targeting of healthy tissues, especially the liver, where viral delivery is <1% of AAV2. In an orthotopic HeyA8 tumor model of EOC, the Provector maintains decreased off-target delivery in the liver and other tissues but with no loss in tumor delivery. Notably, approximately 10% of the injected Provector is still detected in the blood at 24 h while >99% of injected AAV2 has been cleared from the blood by 1 h. Furthermore, mouse serum raised against the Provector is 16-fold less able to neutralize Provector transduction compared to AAV2 serum neutralizing AAV2 transduction (1:200 vs 1:3200 serum dilution, respectively). Thus, the Provector appears to generate less neutralizing antibodies than AAV2. Importantly, serum against AAV2 does not neutralize the Provector as well as AAV2, suggesting that pre-existing antibodies against AAV2 would not negate the clinical application of Provectors. Taken together, we present an EOC gene delivery vector platform based on AAV with decreased off-target delivery without loss of on-target specificity, and greater immunological stealth over the traditional AAV2 gene delivery vector.

Prescribing patterns for FOLFIRINOX in the real world

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Background: FOLFIRINOX therapy is associated with improved outcome in patients with gastrointestinal cancers. The regimen can be associated with significant toxicity and empiric dose modifications are often used. We analyzed 1) real-world prescribing patterns of FOLFIRINOX and 2) toxicity of therapy. Methods: Patients undergoing FOLFIRINOX chemotherapy at an academic, NCI-Designated Comprehensive Cancer Center were identified and electronic medical records reviewed. Patients who received at least one dose of FOLFIRINOX were included. Chemotherapy dose, growth factor use and toxicity data was abstracted for the first 8 weeks. ‘Standard FOLFIRNOX’ was defined as the regimen utilized by Conroy et al (NEJM 2011). Any empiric reduction/withholding of drug dose for cycle 1 was classified as ‘modified FOLFIRINOX’. Bivariate analysis was performed on the data. Results: There were 111 patients seen between 5/2011-3/2017 and 94% had pancreatic cancer. Age range was 29-87 years and 52% were female. 59% received ‘modified FOLFIRINOX’ and 20% received empiric growth factors. Line of therapy for standard vs modified respectively was 71.1% vs 45.5% for 1st, 17.8% vs 36.4% for 2nd, and 11.1% vs 18.2% for beyond 2nd (p = 0.03). Patients with ‘modified FOLFIRINOX’ were more likely to have metastatic disease (p = 0.01), have received second line or beyond, and higher ECOG score (p = 0.03). Patients with ‘modified FOLFIRINOX’ had a trend toward fewer treatment-related ED visits or hospitalization vs ‘standard FOLFIRINOX’ (27.2% vs 42.2% p = 0.10) and fewer treatment delays (25.8% vs 42.2% p = 0.07). Conclusions: In the real world setting, a majority of patients on FOLFIRINOX receive empiric dose modifications. Although modified dose did not translate to a significant difference in ED visits, hospitalizations or treatment delays, there was a trend toward fewer events.

Effective use of electronic medical record (EMR) data in analysis of association between KRAS mutations and depression in colorectal cancer patients

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Background: Previous studies have demonstrated that KRAS mutations were associated with higher rates of depression in patients with metastatic colorectal cancer (CRC). The objective of this study was to evaluate the feasibility of extracting EMR data to examine the association between KRAS mutations and positive screening test for depression in CRC patients. Methods: Retrospective review of stage I to IV CRC patients seen between 2011 and 2015 at an academic, NCI-Designated Comprehensive Cancer Center was performed. At each clinic visit, depression was assessed using the Patient Health Questionnaire-2 (PHQ-2), which is part of the institution’s universal Distress Screening tool. PHQ-2 score of 2 and above was considered positive screening test for depression. PHQ-2 and KRAS mutation data were extracted from the EMR via the Clinical Data Exchange Network bioinformatics tool and confirmed by retrospective chart review. Chi-square test was used to assess the association between KRAS mutation and depression. Multiple imputation was used to impute the missing values. Results: Of the 484 CRC patients, KRAS status was known in 45 cases: 22 (49%) were KRAS mutated and 23 (51%) were KRAS wild type. PHQ-2 score was 0 in 42 cases (93.3%), 1 in 2 cases (4.4%), and ≥2 in 1 case (2.3%). The rate of positive PHQ-2 for KRAS mutated vs wild type was 4% vs 0% (p = 0.36). The result based on 50 imputed datasets suggests a trend towards an association between KRAS mutation and depression (p = 0.09). Conclusions: This study did not demonstrate an association between KRAS mutation and depression in patients with colorectal cancer, probably due to a high proportion of missing data. Bioinformatics studies that extract and analyze EMR data are a feasible and effective platform to assess the association of genomic data with clinical outcomes. Additional validated algorithms and data are needed to further optimize such studies.