Prospective evaluation of drug-drug interactions in ambulatory cancer patients initiated on prophylactic anticoagulation.

INTRODUCTION: Drug options for VTE prophylaxis are increasing for ambulatory cancer patients and data regarding anticoagulant-drug interactions and their relationship to VTE and bleeding are needed to improve care. METHODS: Over one year, 108 cancer patients with high VTE risk were prospectively identified. Potential anticoagulant-drug interactions were ascertained by chart review and graded on need for intervention. Providers selected anticoagulant prophylaxis based on potential drug interactions and patient-provider discussion. A cross-sectional analysis was performed thereafter to evaluate VTE and bleeding endpoints within one year of anticoagulant initiation. RESULTS: The average number of potential drug interactions per patient was higher for warfarin than others (3.04 vs. 1.28 (apixaban), 1.02 (rivaroxaban), and 0.98 (LMWH)). The severity of the interactions based on grade was, for apixaban: 1.6% grade X, 50.8% grade D, and 47.5% grade C; for rivaroxaban: 2.1% grade X, 64.9% grade D, 33.0% grade C; for LMWH, 0% grade X, 66.7% grade D, 33.3% grade C; and for warfarin, 0% grade X, 29.4% grade D, 70.6% grade C. At the end of the investigational period, 11 bleeds and 7 VTEs were reported. Drug combinations significantly associated with an increased bleeding risk were crizotinib with apixaban or rivaroxaban and PPIs with warfarin. The use of sulfamethoxazole-trimethoprim with warfarin was associated with an increased VTE risk. CONCLUSIONS: DOACs had fewer DDIs than warfarin, although interaction severity differed between anticoagulants. Some anticoagulant-drug interactions were associated with bleeding or VTE. Although not powered for analysis, DDI severity did not affect bleeding rates and inversely correlated with VTE risk.

Universal Versus Targeted Screening for Lynch Syndrome: Comparing Ascertainment and Costs Based on Clinical Experience.

BACKGROUND: Strategies to screen colorectal cancers (CRCs) for Lynch syndrome are evolving rapidly; the optimal strategy remains uncertain. AIM: We compared targeted versus universal screening of CRCs for Lynch syndrome. METHODS: In 2010-2011, we employed targeted screening (age < 60 and/or Bethesda criteria). From 2012 to 2014, we screened all CRCs. Immunohistochemistry for the four mismatch repair proteins was done in all cases, followed by other diagnostic studies as indicated. We modeled the diagnostic costs of detecting Lynch syndrome and estimated the 5-year costs of preventing CRC by colonoscopy screening, using a system dynamics model. RESULTS: Using targeted screening, 51/175 (29 %) cancers fit criteria and were tested by immunohistochemistry; 15/51 (29 %, or 8.6 % of all CRCs) showed suspicious loss of ≥1 mismatch repair protein. Germline mismatch repair gene mutations were found in 4/4 cases sequenced (11 suspected cases did not have germline testing). Using universal screening, 17/292 (5.8 %) screened cancers had abnormal immunohistochemistry suspicious for Lynch syndrome. Germline mismatch repair mutations were found in only 3/10 cases sequenced (7 suspected cases did not have germline testing). The mean cost to identify Lynch syndrome probands was ~$23,333/case for targeted screening and ~$175,916/case for universal screening at our institution. Estimated costs to identify and screen probands and relatives were: targeted, $9798/case and universal, $38,452/case. CONCLUSIONS: In real-world Lynch syndrome management, incomplete clinical follow-up was the major barrier to do genetic testing. Targeted screening costs 2- to 7.5-fold less than universal and rarely misses Lynch syndrome cases. Future changes in testing costs will likely change the optimal algorithm.

Correlation of Ecom50 values between mass spectrometers: effect of collision cell radiofrequency voltage on calculated survival yield.

RATIONALE: The determination of the center-of-mass energy at which 50% of a precursor ion decomposes (Ecom(50)) during collision-induced dissociation (CID) is dependent on the chemical structure of the ion as well as the physical and electrical characteristics of the collision cell. The current study was designed to identify variables influencing Ecom(50) values measured on four different mass spectrometers. METHODS: Fifteen test compounds were protonated using + ve electrospray ionization and the resulting ions were fragmented across a range of collision energies by CID. Survival yield versus collision energy curves were then used to calculate Ecom(50) values for each of these [M+H](+) ions on four different mass spectrometers. In addition, the relative recovery of the [M+H](+) ions of eight compounds ranging in molecular weight from 46 to 854 Da were determined at collision cell radiofrequency (RF) voltages ranging from 0 to 600 V. RESULTS: Ecom(50) values determined on the four instruments were highly correlated (r(2) values ranged from 0.953 to 0.992). Although these overall correlations were high, we found different maximum ion recoveries depending on collision cell RF voltage. High-mass ions had greater recovery at higher collision cell RF voltages, whereas low-mass ions had greater recovery at lower collision cell RF voltages as well as a broader range of ion recoveries. CONCLUSIONS: Ecom(50) values measured on four different instruments correlated surprisingly well given the differences in electrical and physical characteristics of the collision cells. However, our results suggest caution when comparing Ecom(50) values or CID spectra between instruments without correcting for the effects of RF voltage on ion transfer efficiency.