Proton Pump Inhibitors and Survival Outcomes in Patients With Metastatic Renal Cell Carcinoma

Despite warnings, co-medication with proton pump inhibitors and dasatinib is common in chronic myeloid leukemia, but XS004, a novel oral dasatinib formulation, provides reduced pH-dependence, minimizing undesirable drug-drug interactions

BACKGROUND

Dasatinib and other tyrosine kinase inhibitors (TKI) have revolutionized the treatment of chronic myeloid leukemia (CML). However, as a lipophilic weak base, crystalline monohydrate, dasatinib (Sprycel®) is poorly soluble, rendering a pH-dependent absorption and a highly variable bioavailability. Thus, co-medication with proton pump inhibitors (PPI) profoundly impairs dasatinib uptake and is clearly recommended against. XS004 is a novel oral immediate release and amorphous solid dispersion (ASD) formulation of dasatinib and is bioequivalent to the original crystalline dasatinib at 30% lower dosages. XS004 is designed to mitigate gastric pH dependency, thus optimizing absorption and bioavailability.

METHODS

We investigated the prevalence of dasatinib and PPI co-medication among chronic-phase CML patients in a real-world setting and assessed the plasma pharmacokinetics (PK) of XS004 with and without PPI co-medication (omeprazole) in healthy volunteers.

RESULTS

Using the Swedish CML and Prescribed Drug Registers, we identified 676 TKI-treated CML patients; 320 (47%) had been prescribed PPI at some point after CML diagnosis. Among dasatinib-treated patients, the 2-year cumulative PPI co-medication was 24%. Interestingly, the 5-year overall survival was significantly lower for TKI-treated CML patients with versus without PPI co-medication (79% vs. 94%; hazard ratio 3.5; 95% confidence interval, 2.1-5.3; p < .0001). When assessing PK of XS004, neither Cmax nor area under the plasma concentration curve levels in plasma were significantly altered by the PPI co-medication.

CONCLUSION

In conclusion, despite warnings, PPI co-medication is common among dasatinib-treated CML patients in a real-world setting. The new XS004 ASD formulation of dasatinib provided, in contrast to original crystalline dasatinib, superior pH independence with stable bioavailability, thereby minimizing drug-drug interactions. This may improve the long-term efficacy and tolerability of dasatinib in CML.

Evaluation of Systemic Treatment Options for Gastrointestinal Stromal Tumours

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the gastrointestinal tract. Surgical treatment is recommended for the majority of localised GIST, while systemic treatment is the cornerstone of management for metastatic or unresectable disease. While a three-year regimen of imatinib is the standard of care in the adjuvant setting, there is no precise recommendation for the duration of neoadjuvant treatment, where imatinib is usually given between 4 and 12 months. Continuous treatment with imatinib at a dose of 400 mg once per day is recommended for most patients with unresectable or metastatic GIST in the first line. An exception is represented by patients with tumours harbouring the imatinib-insensitive PDGFRA D842V mutation who would be better treated with avapritinib. Targeted therapies are also recommended in the presence of NTRK rearrangements and BRAF mutations, although limited data are available. While an increase in the dose of imatinib to 800 mg is an option for the second line, sunitinib is usually considered the standard of care. Similar outcomes were reported for ripretinib in patients with tumours harbouring KIT exon 11 mutation, with significantly fewer side effects. Regorafenib and ripretinib are the standards of care in the third and fourth lines, respectively. The recent development of various systemic treatment options allows for a more personalised approach based on the molecular profile of the GIST, patient characteristics, and the profile of medications' adverse events. A multidisciplinary approach is paramount since combining systemic treatment with locoregional treatment options and supportive care is vital for long-term survival.

Does Proton Pump Inhibitors Decrease the Efficacy of Palbociclib and Ribociclib in Patients with Metastatic Breast Cancer?

Background and Objectives: This investigation aimed to determine the impacts of concurrent proton pump inhibitors (PPIs) on progression-free survival (PFS) in patients with hormone receptor-positive and HER2-negative metastatic breast cancer managed with palbociclib or ribociclib as either the initial or subsequent line of therapy option. Materials and Methods: In this retrospective study, patients were classified as “concurrent PPIs” if PPIs were given for at least two-thirds of the palbociclib or ribociclib therapy period, and “no concurrent PPIs” if no PPIs were given during the period of palbociclib or ribociclib therapy. Each patient was also classified as endocrine-sensitive or endocrine-resistant according to the duration of previous endocrine responses. “Concurrent PPIs” and “no concurrent PPIs” groups were compared with each other in terms of PFS. This comparison was performed for both ribociclib and palbociclib groups. Results: The research included 220 patients in total. The PFS of 57 patients on palbociclib using concomitant PPIs was 14.4 months. Among 63 patients using palbociclib without concomitant PPIs, the PFS was 15.8 months. No statistically significant difference was found with PPI use (p = 0.82). Among 29 patients using ribociclib concurrently with PPIs, the PFS was 22.4 months. Among 71 patients using ribociclib without PPIs, the PFS was 20.2 months. No statistically significant difference was found with PPI use (p = 0.40). Conclusion: The results of our investigation showed that concomitant use of the most commonly used PPIs in the study (lansoprazole, pantoprazole, and esomeprazole) with palbociclib or ribociclib did not have any detrimental effects on PFS. Where appropriate, PPIs can be used concurrently with palbociclib and ribociclib. However, the effect of PPIs on cycling-dependent kinase 4/6 inhibitors deserves further investigation.

Drug-drug interactions with proton pump inhibitors in cancer patients: an underrecognized cause of treatment failure

New concepts and drugs have revolutionized medical treatment for cancers. These drugs, which are very expensive and usually well tolerated, have dramatically improved cancer prognosis. We must use them wisely for patients to fully benefit. Gastric acid antisecretory drugs and particularly proton pump inhibitors (PPIs) revolutionized the treatment of gastroduodenal ulcers and severe gastroesophageal reflux, but are frequently overused for symptomatic treatment of epigastric pain or heartburn. Long-term acid suppression may alter the efficacy of many anticancer drugs, such as tyrosine kinase inhibitors (TKIs), cyclin-dependent kinase (CDK) 4/6 inhibitors and immune checkpoint inhibitors (ICIs), by either decreasing gastric acid secretion and thus drug absorption, or by modifying the gut microbiome that modulates the response to ICIs. Oncologists thus need to pay particular attention to the concomitant use of PPIs and anticancer drugs. These interactions translate into major clinical impacts, with demonstrated loss of efficacy for some TKIs (erlotinib, gefitinib, pazopanib), and conflicting results with many other oral drugs, including capecitabine and CDK 4/6 inhibitors. Furthermore, the profound changes in the gut microbiome due to using PPIs have shown that the benefit of using ICIs may be suppressed in patients treated with PPIs. As the use of PPIs is not essential, we must apply the precautionary principle. The first sentence of a recent Comment in Nature was "Every day, millions of people are taking medications that will not help them". We fear that every day millions of cancer patients are taking medications that harm them. While this may well be only association and not causation, there is enough to make us pause until we reach a clear answer. All these data should encourage medical oncologists to refrain from prescribing PPIs, explaining to patients the risks of interaction in order to prevent inappropriate prescription by another physician.

The Association between Baseline Proton Pump Inhibitors, Immune Checkpoint Inhibitors, and Chemotherapy: A Systematic Review with Network Meta-Analysis

(1) Although emerging evidence suggests that proton pump inhibitor (PPI)-induced dysbiosis negatively alters treatment response to immune checkpoint inhibitors (ICIs) in cancer patients, no study systematically investigates the association between PPIs, ICIs, and chemotherapy; (2) Cochrane Library, Embase, Medline, and PubMed were searched from inception to 20 May 2022, to identify relevant studies involving patients receiving ICIs or chemotherapy and reporting survival outcome between PPI users and non-users. Survival outcomes included overall survival (OS) and progression-free survival (PFS). Network meta-analyses were performed using random-effects models. p-scores, with a value between 0 and 1, were calculated to quantify the treatment ranking, with a higher score suggesting a higher probability of greater effectiveness. We also conducted pairwise meta-analyses of observational studies to complement our network meta-analysis; (3) We identified 62 studies involving 26,484 patients (PPI = 8834; non-PPI = 17,650), including non-small cell lung cancer (NSCLC), urothelial carcinoma (UC), melanoma, renal cell carcinoma (RCC), hepatocellular carcinoma (HCC), and squamous cell carcinoma (SCC) of the neck and head. Eight post-hoc analyses from 18 randomized-controlled trials were included in our network, which demonstrated that, in advanced NSCLC and UC, patients under ICI treatment with concomitant PPI (p-score: 0.2016) are associated with both poorer OS (HR, 1.49; 95% CI, 1.37 to 1.67) and poorer PFS (HR, 1.41; 95% CI, 1.25 to 1.61) than those without PPIs (p-score: 1.000). Patients under ICI treatment with concomitant PPI also had poorer OS (HR, 1.18; 95% CI, 1.07 to 1.31) and poorer PFS (HR, 1.30; 95% CI, 1.14 to 1.48) in comparison with those receiving chemotherapy (p-score: 0.6664), implying that PPIs may compromise ICI's effectiveness, making it less effective than chemotherapy. Our pairwise meta-analyses also supported this association. Conversely, PPI has little effect on patients with advanced melanoma, RCC, HCC, and SCC of the neck and head who were treated with ICIs; (4) "PPI-induced dysbiosis" serves as a significant modifier of treatment response in both advanced NSCLC and UC that are treated with ICIs, compromising the effectiveness of ICIs to be less than that of chemotherapy. Thus, clinicians should avoid unnecessary PPI prescription in these patients. "PPI-induced dysbiosis", on the other hand, does not alter the treatment response to ICIs in advanced melanoma, RCC, HCC, and SCC of the head and neck.

The status of TKI/acid-suppressant concomitant use in 44 hospitals in China: A cross-sectional descriptive study

The irrational use of tyrosine kinase inhibitors (TKIs) has attracted increasing attention, especially because of drug-drug interactions. The objective of this study was to analyze TKI prescriptions and evaluate the rationality of concomitant use of TKIs and acid-suppressants. TKI prescriptions from 2016 to 2018 were collected from hospitals in Beijing, Guangzhou, Hangzhou, and Zhengzhou for 40 d/yr. Focusing on the data in 2018, we analyzed the pharmacoeconomic indicators of TKIs and the number and proportion of different coprescriptions. The evaluation criteria for coprescriptions were based on clinical literature and package inserts. A total of 41,738 TKI prescriptions were assessed. The total dose and sales of imatinib were the highest, the medication days and defined daily doses of gefitinib were the highest, and the highest defined daily cost was sunitinib. Meanwhile, there were 17 TKIs with drug utilization indices of ≤ 1.0. The irrational combination rate of prescriptions of non-cancer-related departments was high in 3 cities, but not Hangzhou. The irrational combination rate of prescription of inpatient prescriptions was > 23% in the 4 cities. The combined use of TKIs and acid-suppressants is common in China and may have a clear or potential impact on the pharmacokinetics, pharmacodynamics, and adverse drug reactions of TKIs. Therefore, it is urgent to implement necessary interventions to stop such irrational use or if the combined use is necessary, to correct adverse consequences. The aims should be to achieve safe and effective use of TKIs and reduce unnecessary costs.

An update on drug-drug interactions associated with proton pump inhibitors

INTRODUCTION

Proton pump inhibitors (PPIs) block the gastric H/K-ATPase, therefore inhibiting acid gastric secretion, leading to an increased pH (>4). They account for an extremely high number of prescriptions worldwide. Numerous drug-drug interactions have been described with PPIs, but all the described interactions do not have clinical significance.

AREAS COVERED

This review will discuss the latest updates on drug-drug interactions with PPIs, focusing on the last ten-year publications in the following areas: anti-infective agents, anticancer drugs, antiplatelet agents and anticoagulants, and antidiabetics.

EXPERT OPINION

Although pharmacokinetic interactions of PPIs have been described with many drugs, their clinical relevance remains controversial. However, given the extremely high number of people being treated with PPIs, clinicians should remain vigilant for interactions that may be clinically significant and require dose adjustment or therapeutic monitoring. Interestingly, not all PPIs have the same pharmacokinetic and pharmacodynamic profile, with some having a strong potential to inhibit CYP2C19, such as omeprazole, esomeprazole and lansoprazole, while others, pantoprazole, rabeprazole and dexlansoprazole, are weak CYP2C19 inhibitors. These may be preferred depending on co-prescribed treatments.In addition, new formulations have been developed to prevent some of the gastric pH-dependent drug interactions and should be evaluated in further large-scale prospective comparative studies.

Proton pump inhibitors may reduce the efficacy of ribociclib and palbociclib in metastatic breast cancer patients based on an observational study

INTRODUCTION

Approximately 20-33% of all cancer patients are treated with acid-reducing agents (ARAs), most commonly proton pump inhibitors (PPIs), to reduce gastroesophageal reflux disease symptoms. Palbociclib and ribociclib are weak bases so their solubility depends on different pH. The solubility of palbociclib dramatically decreases to < 0.5 mg/ml when pH is above 4,5 but ribociclibs' solubility decreases when pH increases above 6,5. In the current study, we aimed to investigate the effects of concurrent PPIs on palbociclib and ribociclib efficacy in terms of progression-free survival in metastatic breast cancer (mBC) patients.

PATIENTS AND METHODS

We enrolled hormone receptor-positive, HER2-negative mBC patients treated with endocrine treatment (letrozole or fulvestrant) combined palbociclib or ribociclib alone or with PPI accompanying our observational study. During palbociclib/ribociclib therapy, patients should be treated with "concurrent PPIs" defined as all or more than half of treatment with palbociclib/ribociclib, If no PPI was applied, it was defined as 'no concurrent PPI', those who used PPI but less than half were excluded from the study. All data was collected from real-life retrospectively.

RESULTS

Our study included 217 patients, 105 of whom received palbociclib and 112 received ribociclib treatment. In the study population CDK inhibitor treatment was added to fulvestrant 102 patients ( 47%), to letrozole 115 patients (53%). In the Palbociclib arm fulvestrant/letrozole ratio was 53.3/46.7%, in the ribociclib arm it was 41.07/58.93%. Of 105 patients who received palbociclib, 65 were on concomitant PPI therapy, 40 were not. Of the 112 patients who received ribociclib, 61 were on concomitant PPI therapy, 51 were not. In the palbociclib group, the PFS of the patients using PPIs was shorter than the PFS of the patients not using (13.04 months vs. unreachable, p < 0.001). It was determined that taking PPIs was an independent predictor of shortening PFS (p < 0.001) in the multivariate analysis, In the ribociclib group, the PFS of the patients using PPIs was shorter than the PFS of the patients not using (12.64 months vs. unreachable, p = 0.003). It was determined that taking PPIs was single statistically independent predictor of shortening PFS (p = 0.003, univariate analysis).

CONCLUSIONS

Our study demonstrated that concomitant usage of PPIs was associated with shorter PFS in mBC treated with both ribociclib and especially palbociclib. If it needs to be used, PPI selection should be made carefully and low-strength PPI or other ARAs (eg H2 antagonists, antacids) should be preferred.

Drug-Drug Interactions With Over-The-Counter Medicines: Mind the Unprescribed

BACKGROUND

This review provides a summary of the currently available clinical data on drug-drug interactions (DDIs) involving over-the-counter (OTC) medicines. It aims to educate and increase awareness among health care providers and to support decisions in daily practice.

METHODS

An extensive literature search was performed using bibliographic databases available through PubMed.gov. An initial structured search was performed using the keywords "drug-drug-interaction AND (over-the-counter OR OTC)," without further restrictions except for the language. The initial results were screened for all described DDIs involving OTC drugs, and further information was gathered specifically on these drugs using dedicated database searches and references found in the bibliography from the initial hits.

RESULTS

From more than 1200 initial hits (1972-June 2021), 408 relevant publications were screened for DDIs involving OTC drugs, leading to 2 major findings: first, certain types of drug regimens are more prone to DDIs or have more serious DDI-related consequences, such as antiretroviral, anti-infective, and oral anticancer therapies. Second, although most DDIs involve OTC drugs as the perpetrators, some prescription drugs (statins or phosphodiesterase-5 inhibitors) that currently have OTC status can be identified as the victims in DDIs. The following groups were identified to be frequently involved in DDIs: nonsteroidal anti-inflammatory drugs, food supplements, antacids, proton-pump inhibitors, H2 antihistamines, laxatives, antidiarrheal drugs, and herbal drugs.

CONCLUSIONS

The most significant finding was the lack of high-quality evidence for commonly acknowledged interactions. High-quality interaction studies involving different phenotypes in drug metabolism (cytochrome P450) and distribution (transporters) are urgently needed. This should include modern and critical drugs, such as oral anticancer medications and direct oral anticoagulants.

Proton Pump Inhibitors and Cancer: Current State of Play

Background: Proton pump inhibitors (PPIs) are one of the most widely used drugs worldwide and are overprescribed in patients with cancer; there is increasing evidence of their effects on cancer development and survival. The objective of this narrative review is to comprehensively identify cancer medications that have clinically meaningful drug–drug interactions (DDIs) with PPIs, including loss of efficacy or adverse effects, and to explore the association between PPIs and cancer.

Methods: A PubMed search of English language studies published from 1 January 2016, to 1 June 2021 was conducted. The search terms included “proton pump inhibitors,” “cancer,” “chemotherapy,” “immunotherapy,” “hormonotherapies,” “targeted therapies,” “tyrosine kinase inhibitors,” and “gut microbiome”. Recent and relevant clinical trials, meta-analyses, and reviews were included.

Results: PPIs may have pro-tumor activity by increasing plasma gastrin levels or anti-tumor activity by inhibiting V-ATPases. However, their impact on cancer survival remains unclear. PPIs may decrease the efficacy of some antineoplastic agents through direct DDIs (e.g., some tyrosine kinase inhibitors, capecitabine, irinotecan, methotrexate). More complex DDIs seem to exist for immunotherapies with indirect interactions through the microbiome. PPIs worsen hypomagnesemia, bone loss, iron, and vitamin B12 deficiencies but may have a protective effect on the renal system.

Discussion/Conclusions: PPIs may interact with the cancer microbiome and the efficacy of various antineoplastic agents, although only a few DDIs involving PPIs are clinically significant. Further pharmaco-epidemiological studies are warranted, but physicians should be aware of the potential consequences of PPI use, which should be dose appropriate and prescribed according to guidelines.

Long-Term Use of Proton Pump Inhibitors in Cancer Patients: An Opinion Paper

Simple Summary

Proton pump inhibitors are frequently used in cancer patients to alleviate some symptoms, epigastric pain or heartburn. However, acid suppression decreases the absorption of some oral-targeted anticancer treatments (tyrosine kinase inhibitors, CDK4/6 inhibitors) and induces changes in the gut microbiome. Recent data are showing that these interactions have important clinical impacts and medical oncologists and patients must be aware of these possible interactions.

Abstract

Multikinase inhibitors (MKIs), and particularly tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (CPIs), are currently some of the major breakthroughs in cancer treatment. Proton pump inhibitors (PPIs) revolutionised the treatment of acid-related diseases, but are frequently overused for epigastric pain or heartburn. However, long-term acid suppression from using PPIs may lead to safety concerns, and could have a greater impact in cancer patients undergoing therapy, like bone fractures, renal toxicities, enteric infections, and micronutrient deficiencies (iron and magnesium). Moreover, acid suppression may also affect the pharmacokinetics of drugs (at least during acid suppression) and decrease the absorption of many molecularly-targeted anticancer therapies, which are mostly weak bases with pH-dependent absorption. This type of drug-drug interaction may have detrimental effects on efficacy, with major clinical impacts described for some orally administrated targeted therapies (erlotinib, gefitinib, pazopanib, palbociclib), and conflicting results with many others, including capecitabine. Furthermore, the long-term use of PPIs results in severe alterations to the gut microbiome and recent retrospective analyses have shown that the benefit of using CPIs was suppressed in patients treated with PPIs. These very expensive drugs are of great importance because of their efficacy. As the use of PPIs is not essential, we must apply the precautionary principle. All these data should encourage medical oncologists to refrain from prescribing PPIs, explaining to patients the risks of interaction in order to prevent inappropriate prescription by another physician.

Concomitant Proton Pump Inhibitors and Outcome of Patients Treated with Nivolumab Alone or Plus Ipilimumab for Advanced Renal Cell Carcinoma

BACKGROUND

Immune checkpoint inhibitors (ICIs) represent the standard of care as first- or second-line treatment in patients with renal cell carcinoma (RCC). Proton pump inhibitors (PPIs) are among the most prescribed drugs worldwide and are known to affect gut microbiota, which is gaining interest in its association with outcomes for patients on ICIs.

OBJECTIVE

The aim of this study was to evaluate the impact of PPIs on outcomes in RCC patients receiving immunotherapy.

PATIENTS AND METHODS

We retrospectively collected data from patients with metastatic RCC who received the combination of ipilimumab and nivolumab for first-line treatment (Cohort 1) or single-agent nivolumab for second-line or third-line treatment (Cohort 2) from five international centers with expertise in the treatment of RCC. Data about clinicopathological characteristics, PPI use, and outcome on ICIs were collected. Endpoints of the study were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Two hundred and eighteen patients (71% male, median age 61 years) were included in the analysis, 62 in Cohort 1 (including 25 patients receiving PPIs) and 156 in Cohort 2 (including 88 patients receiving PPIs), and were followed up for a median of 42 months. In Cohort 1, no difference was observed in ORR (48% vs 57%; p = 0.203), PFS (12.2 vs 8.5 months; p = 0.928), or OS (not reached [NR] vs 27.3 months; p = 0.84). In Cohort 2, no difference was observed in ORR (32% vs 28%; p = 0.538), PFS (6.7 vs 9.0 months; p = 0.799), or OS (16.0 vs 26.0 months; p = 0.324).

CONCLUSIONS

In patients with RCC, concomitant PPI use did not seem to affect survival outcomes on ICIs, either as combination therapy or monotherapy.

Importance of medication reconciliation in cancer patients

Cancer patients are a complex and vulnerable population whose medication history is often extensive. Medication reconciliations in this population are especially essential, since medication discrepancies can lead to dire outcomes. This commentary aims to describe the significance of conducting medication reconciliations in this often-forgotten patient population. We discuss additional clinical interventions that can arise during this process as well. Medication reconciliations provide the opportunity to identify and prevent drug-drug and herb-drug interactions. They also provide an opportunity to appropriately adjust chemotherapy dosing according to renal and hepatic function. Finally, reconciling medications can also provide an opportunity to identify and deprescribe inappropriate medications. While clinical impact appears evident in this landscape, evidence of economic impact is lacking. As more cancer patients are prescribed a combination of oral chemotherapies, intravenous chemotherapies and non-anticancer medications, future studies should evaluate the advantages of conducting medication reconciliations in these patient populations across multiple care settings.

Drug-drug interactions between palbociclib and proton pump inhibitors may significantly affect clinical outcome of metastatic breast cancer patients

Background

Proton-pump-inhibitors (PPIs) are frequently prescribed for the management of anticancer drug-related gastrointestinal symptoms. Palbociclib is a weak base with pH-dependent solubility and potential drug-drug interaction at the absorption level may affect clinical pharmacokinetics. The current study was aimed at investigating the effect of co-administration of PPIs and palbociclib on progression-free survival (PFS) in metastatic breast cancer (mBC) patients.

Patients and methods

Patients affected by estrogen receptor-positive, human epidermal growth factor receptor 2-negative mBC, who were candidates for first-line treatment with palbociclib, were enrolled in this retrospective observational study. Patients were defined as ‘no concomitant PPIs’ if no PPIs were administered during palbociclib treatment, and as ‘concomitant PPIs’ if the administration of PPIs covered the entire or not less than two-thirds of treatment with palbociclib. All clinical interventions were made according to clinical practice.

Results

A total of 112 patients were enrolled in the study; 56 belonged to the ‘no concomitant PPIs’ group and 56 to the ‘concomitant PPIs’ group. Seventy-one patients were endocrine-sensitive and received palbociclib and letrozole, and 43 were endocrine-resistant and were treated with palbociclib and fulvestrant. The most prescribed PPI was lansoprazole. Patients taking PPIs had a shorter PFS than those taking palbociclib and endocrine therapy alone (14.0 versus 37.9 months, P < 0.0001). Multivariate analysis confirmed concomitant PPIs as the only independent predictive factor for shorter PFS (P = 0.0002). PFS was significantly longer in estrogen-sensitive mBC with no concomitant PPIs compared with patients taking PPIs or estrogen-resistant patients, with and without PPIs (P < 0.0001). No correlation with adverse events was found when considering grade >2 hematological toxicities [Common Terminology Criteria for Adverse Events (CTCAE) scale].

Conclusions

The present study demonstrates that concomitant use of PPIs in mBC patients treated with palbociclib has a detrimental effect on PFS. Therefore, it is recommended to prescribe PPIs with caution in these patients, strictly adhering to the indications in the summary of product characteristics (RCP).

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PPIs are widely used in cancer patients to manage chemotherapy-related gastrointestinal adverse events.

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Palbociclib is a weak base with a pH-dependent solubility.

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Breast cancer patients treated with palbociclib and PPIs have significantly shorter PFS.

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Drug-drug interactions should be clearly evaluated in patients taking PPIs.

Impact of Concomitant Cardiovascular Medication on Survival of Metastatic Renal Cell Carcinoma Patients Treated with Sunitinib or Pazopanib in the First Line

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) are often elderly and have various comorbidities, including cardiovascular diseases. Although these patients have extensive co-exposure to targeted therapy and cardiovascular drugs, the impact of this co-exposure on outcomes for patients with mRCC remains unclear.

OBJECTIVE

Our objective was to evaluate the association between the use of cardiovascular medication and survival of patients with mRCC.

METHODS

The study included 343 consecutive patients with mRCC treated with sunitinib or pazopanib in the first line. Clinical data obtained from the Renal Cell Carcinoma Information System (RENIS) clinical registry and hospital information systems were retrospectively analyzed. Progression-free survival (PFS) and overall survival (OS) were compared according to the use of common medications, including antihypertensives (i.e., β-blockers [BBs], angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and diuretics), acetylsalicylic acid (aspirin), statins, and proton pump inhibitors.

RESULTS

The univariate Cox analysis evaluating the impact of the assessed comedications on patient survival revealed that only BBs were significantly associated with PFS (hazard ratio [HR] 0.533, p < 0.001) and OS (HR 0.641, p = 0.006). The median PFS and OS for users of BBs was 18.39 and 37.60 months versus 8.16 and 20.4 months for patients not using BBs (p < 0.001 and p < 0.001, respectively). The Cox multivariate analysis showed that the use of BBs was a significant factor for both PFS (HR 0.428, p = 0.001) and OS (HR 0.518, p = 0.001).

CONCLUSIONS

The results of this retrospective study suggest that the use of BBs is associated with favorable outcomes for patients with mRCC treated with sunitinib or pazopanib in the first line.

Prevalence of drug-drug interactions in sarcoma patients: key role of the pharmacist integration for toxicity risk management

BACKGROUND

The risk of drug-drug interactions (DDI) has become a major issue in cancer patients. However, data in sarcoma patients are scarce. We aimed to evaluate the frequency and the factors associated with DDI with antitumor treatments, and to evaluate the impact of a pharmacist evaluation before anticancer treatment.

PATIENTS AND METHODS

We performed a retrospective review of consecutive sarcoma patients starting chemotherapy (CT) or Tyrosine kinase inhibitor (TKI). A pharmacist performed medication reconciliation and established an early toxicity risk assessment. Potential DDI with antitumor drugs were identified using Micromedex electronic software.

RESULTS

One hundred and twenty-two soft-tissue and 80 bone sarcoma patients (103 males, median age 50 years,) were included before CT (86%) or TKI (14%). The median number of medications was 3; 34 patients (22% of patients with medication reconciliation) reported complementary medicine use. 37 potential DDI classified as major, were identified (12% of the 243 pre-therapeutic assessments). In multivariate analysis, TKI (p < 0.0001), proton pump inhibitor (p = 0.026) and antidepressant (p < 0.001) were identified as risk factors of DDI (p < 0.02). Only marital status (p = 0.003) was associated with complementary medicine use. A pharmacist performed 157 medication reconciliations and made 71 interventions among 59 patients (37%). In multivariate analysis, factors associated with pharmacist intervention were: complementary medicines (p = 0.004), drugs number (p = 0.005) and treatment with TKI (p = 0.0002) CONCLUSIONS: Clinical interventions on DDI are more frequently required among sarcoma patients treated with TKI than CT. Multidisciplinary risk assessment including a medication reconciliation by a pharmacist could be crucial to prevent DDI with TKI.

Controversial link between proton pump inhibitors and anticancer agents: review of the literature

Drug-drug interactions represent a topic of great interest, not only due to the risk of unexpected adverse events but also due to the possibility of altering the effectiveness of a specific treatment. Inappropriate or concomitant use of drugs can often lead to changes in the bioavailability of various compounds, resulting in pharmacokinetic alterations. A recent example is the concomitant administration of proton pump inhibitors (PPIs) and anticancer agents. PPIs are overused beyond their classic indications, resulting in a high risk of interactions with other drugs, such as anticancer agents, both PO and intravenous. However, the real clinical impact of concomitant acid suppression therapy and anticancer therapies remains controversial and is not yet fully understood. Certainly, the gut microbiota plays a key role in regulating the response of the immune system, and PPIs can significantly alter the gut microbiome, resulting in gut dysbiosis. Indeed, while the link sometimes appears to lead to negative outcomes, as in the case of immunotherapy, oral capecitabine, or tyrosine kinase inhibitors, in other cases, it seems to enhance the effectiveness of intravenous chemotherapy. In this review, I analyse the possible drug interactions between PPIs and the main classes of anticancer drugs.

Evaluation of the Effect of Proton Pump Inhibitors on the Efficacy of Dacomitinib and Gefitinib in Patients with Advanced Non-Small Cell Lung Cancer and EGFR-Activating Mutations

Introduction

Dacomitinib and gefitinib are irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) indicated for the first-line treatment of patients with advanced non-small cell lung cancer (NSCLC) and EGFR-activating mutations. Pharmacokinetic (PK) studies in healthy volunteers suggested that acid-reducing drugs such as proton pump inhibitors (PPI) decreased dacomitinib and gefitinib exposure by limiting the pH-dependent absorption. This analysis retrospectively evaluates the effect of concomitant PPI use on dacomitinib exposure and on progression-free survival (PFS) and overall survival (OS) in patients treated with dacomitinib 45 mg QD or gefitinib 250 mg QD in a 1:1 randomized phase 3 study (ARCHER 1050).

Methods

The analysis grouped all patients (n = 452) treated in each arm of the study as non-PPI users, PPI users, or extensive PPI users. PFS and OS data were presented by Kaplan–Meier plots and analyzed using Cox proportional hazards models. Dacomitinib exposure was compared using a linear mixed-effects model.

Results

Results showed that dacomitinib PFS and OS did not differ significantly when comparing PPI users (N = 59) to non-PPI users (N = 152), while extensive PPI users (N = 24) had shorter PFS [hazard ratio (HR): 1.94, p = 0.011] and OS (HR: 1.77, p = 0.027) when compared to non-PPI users. For patients treated with gefitinib, PFS did not differ significantly when comparing PPI users (N = 51) and extensive PPI users (N = 19) to non-PPI users (N = 159); however, both PPI users (HR: 1.65, p = 0.007) and extensive PPI users (HR: 1.70, p = 0.050) had shorter OS when compared to non-PPI users. Further analysis by adjusting potential confounders indicated no statistically significant differences in PFS or OS between any PPI user vs. non-PPI user groups in the dacomitinib and gefitinib arms. PPI use did not appear to affect dacomitinib exposure.

Conclusion

In conclusion, PPI use in patients with NSCLC likely has minimal impact on dacomitinib or gefitinib efficacy despite decreased absorption of these drugs observed in PK studies.

Trial Registration

ClinicalTrials.gov identifier, NCT01774721

Mechanistic Modelling Identifies and Addresses the Risks of Empiric Concentration-Guided Sorafenib Dosing

The primary objective of this study is to evaluate the capacity of concentration-guided sorafenib dosing protocols to increase the proportion of patients that achieve a sorafenib maximal concentration (C_max) within the range 4.78 to 5.78 μg/mL. A full physiologically based pharmacokinetic model was built and validated using Simcyp^® (version 19.1). The model was used to simulate sorafenib exposure in 1000 Sim-Cancer subjects over 14 days. The capacity of concentration-guided sorafenib dose adjustment, with/without model-informed dose selection (MIDS), to achieve a sorafenib C_max within the range 4.78 to 5.78 μg/mL was evaluated in 500 Sim-Cancer subjects. A multivariable linear regression model incorporating hepatic cytochrome P450 (CYP) 3A4 abundance, albumin concentration, body mass index, body surface area, sex and weight provided robust prediction of steady-state sorafenib C_max (R² = 0.883; p < 0.001). These covariates identified subjects at risk of failing to achieve a sorafenib C_max ≥ 4.78 μg/mL with 95.0% specificity and 95.2% sensitivity. Concentration-guided sorafenib dosing with MIDS achieved a sorafenib C_max within the range 4.78 to 5.78 μg/mL for 38 of 52 patients who failed to achieve a C_max ≥ 4.78 μg/mL with standard dosing. In a simulation setting, concentration-guided dosing with MIDS was the quickest and most effective approach to achieve a sorafenib C_max within a designated range.

The Effect of Concomitant Proton Pump Inhibitor and Cabozantinib on the Outcomes of Patients with Metastatic Renal Cell Carcinoma

INTRODUCTION

Cabozantinib is an oral tyrosine kinase inhibitor that is approved for the treatment of metastatic renal cell carcinoma (mRCC). Cabozantinib is a weak base that exhibits a pH-dependent solubility profile in vitro which raises concerns about its bioavailability in patients treated with proton pump inhibitors (PPIs). The purpose of this study was to investigate whether PPI use has an impact on the efficacy, safety, and residual concentration (Ctrough) of cabozantinib in patients with mRCC.

MATERIALS AND METHODS

This is a retrospective review of a prospectively collected electronic database of patients with mRCC who received cabozantinib at Gustave Roussy between February 2014 and December 2018. The Kaplan-Meier method was used for survival analysis and the Cox proportional-hazard model for uni- and multivariate analysis. In parallel, we conducted a pharmacokinetic study of cabozantinib in a distinct cohort of 50 mRCC patients, in which cabozantinib Ctrough was assayed using a validated tandem mass spectrometry-liquid chromatography method.

RESULTS

We identified 99 patients treated with cabozantinib, including 43 patients being PPI users. With a median follow-up of 30.3 months, PPI users showed similar progression-free survival and overall survival outcomes compared with PPI nonusers. Similarly, the incidence of adverse events was not significantly different between the PPI users and nonusers, although PPI users required dose reductions more often. In the independent pharmacokinetic cohort, of whom 21 received PPI concomitantly, Ctrough was similar between the two groups.

CONCLUSION

In line with the pharmacologic data, the concomitant use of PPI does not significantly impact the efficacy or safety of cabozantinib in patients with mRCC.

IMPLICATIONS FOR PRACTICE

Drug interactions, especially between targeted therapies and proton pump inhibitors (PPI), were shown to potentially impact the outcomes of cancer patients. Cabozantinib, a current therapeutic standard in metastatic renal cell carcinoma (mRCC), exhibits a pH-dependent solubility profile, which raises concerns about its bioavailability in patients treated with proton pump inhibitors (PPI). At the present time, there is no evidence regarding the effect of PPIs on cabozantinib's efficacy and safety in patients with mRCC. This study found that the concomitant use of PPI during cabozantinib treatment in mRCC patients does not appear to impact the residual concentration, efficacy, and safety of cabozantinib in a real-life context.

Proton Pump Inhibitors and Oncologic Treatment Efficacy: A Practical Review of the Literature for Oncologists

Proton pump inhibitors (PPIs) are the most commonly used anti-acid drugs worldwide, including among cancer patients. However, drug-drug interactions between PPIs and other agents may lead to decreased drug absorption with possible reduced therapeutic benefit, or even increased toxicity. Unfortunately, only scarce data exist regarding the safety of concomitant PPI use with anti-cancer agents. We aim at reviewing current evidence on this possible interaction by dividing anti-cancer agents by class. Until further data is available, we encourage healthcare providers to limit unnecessary PPI overuse.

Association of Gastric Acid Suppression and Sorafenib Efficacy in Advanced Hepatocellular Carcinoma

BACKGROUND

Recent studies have revealed that coadministration of gastric acid suppressants reduces the efficacy of the tyrosine kinase inhibitors erlotinib and sunitinib in patients with non-small cell lung cancer and renal cell carcinoma, respectively. The authors have therefore assessed if the concurrent use of gastric acid suppressants and sorafenib impairs outcomes in patients with advanced hepatocellular carcinoma (HCC).

METHODS

A retrospective analysis was conducted on all patients treated with sorafenib for advanced HCC at a single tertiary referral unit in the United Kingdom, between January 2008 and January 2014. A multivariate Cox proportional hazard model was used to assess the effect of the concomitant use of gastric acid suppression and sorafenib on progression-free survival (PFS) and overall survival (OS).

RESULTS

Data were collected from 197 patients, of which 182 could be assessed for this study; 77 (42%) were on concurrent gastric acid suppression therapy. After adjusting for imbalances between the groups, a Cox regression analysis gave an adjusted hazard ratio for the concurrent acid suppression group compared with the no acid suppression group of 5.4 (95% confidence interval, 3.6-7.9) for PFS and 1.85 (95% confidence interval, 1.3-2.6) for OS.

CONCLUSIONS

This single-center experience shows that patients with advanced HCC taking sorafenib and concomitant gastric acid suppression therapy have significantly inferior PFS and OS. This is the first time that this negative interaction has been reported and further prospective validation is warranted.

Acid-suppressive agents and survival outcomes in patients with cancer: a systematic review and meta-analysis

BACKGROUND

Patients with cancer often receive acid-suppressive agents (ASAs) to treat common gastroesophageal reflux and peptic ulcer diseases. Our systematic review addresses the association between ASAs and survival outcomes in these patients.

METHODS

We searched MEDLINE, EMBASE, and Cochrane until December 2019, including randomized controlled trials (RCTs), quasi-RCTs, and observational studies concerning ASAs that reported progression-free survival (PFS) and/or overall survival (OS). We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) using the random-effects model, and assessed heterogeneity with I² statistic.

RESULTS

We included 45,626 patients from 7 RCTs and 18 observational studies, including esophageal/gastric, colorectal, pancreatic, lung, breast, prostate, kidney, and other cancers. Five studies showed that ASAs in lung cancer patients received tyrosine kinase inhibitors (TKIs) had significantly worse PFS (HR 1.64, 95% CI 1.14 - 2.37, I² = 57%) and OS (HR 1.13, 95% CI 1.05 - 1.21, I² = 0%) than nonusers. Each of five studies found no significant association between ASAs and OS in esophageal/gastric (HR 0.91, 95% CI 0.77 - 1.09, I² = 32%) or colorectal cancer patients (HR 1.33, 95% CI 0.96- 1.85, I² = 0%). ASAs were not significantly associated with an OS in patients with kidney cancer (HR 1.04, 95% CI 0.96 - 1.13, I² = 28%).

CONCLUSIONS

Meta-analysis showed that ASAs significantly associated with an increased mortality risk in lung cancer patients treated TKIs, but not in patients with esophageal/gastric, colorectal, or kidney cancer. Until further studies confirm these results, caution should be used when administering ASAs and TKIs to patients with lung cancer.

Effect of comorbidities/comedications on sunitinib outcomes for metastatic renal cell carcinoma: the STAR-TOR registry

Aim: Examine the effects of baseline hypertension (HTN) and statin or proton pump inhibitor (PPI) use on sunitinib treatment outcomes in STAR-TOR, a real-world registry. Materials & methods: Presence or absence of HTN and use or nonuse of statins or PPIs were determined at registry entry. End points included overall survival (OS) and progression-free survival (PFS). Results: Data were from 557 patients. Presence or absence of HTN did not affect OS or PFS. PFS (median [95% CI]) was longer in statin users (9.4 [6.5-13.6] months) versus nonusers (6.9 [5.7-8.2] months) (p = 0.0442). OS was shorter in PPI users (20.2 [14.9-28.3] months) versus nonusers (25.7 [22.7-33.0] months) (p = 0.0212). Conclusion: Comorbidities and comedications may affect real-world sunitinib treatment outcomes. Clinical Trial Registration: NCT00700258 (ClinicalTrials.gov).

The effect of proton pump inhibitors on survival outcomes in advanced hepatocellular carcinoma treated with sorafenib

PURPOSE

Sorafenib is an oral tyrosine kinase inhibitor (TKI) and first-line treatment option for advanced hepatocellular carcinoma (HCC). Preliminary evidence indicates proton pump inhibitors (PPI) may affect the absorption of TKIs through decreased gut dissolution. This study aims to evaluate the impact of PPI use on the survival outcomes of advanced HCC patients treated with sorafenib.

METHODS

The study was a secondary analysis of individual-participant data from the phase III clinical trial NCT00699374. Cox proportional hazard analysis was used to evaluate the association between baseline PPI use and survival outcomes. Overall survival (OS) was the primary outcome with progression-free survival (PFS) secondary.

RESULTS

In a cohort of 542 advanced HCC patients initiating sorafenib treatment, 122 were concomitantly using a PPI at baseline. No significant associations between baseline PPI use and OS were identified on univariable (HR [95% CI]; 1.01 [0.80-1.28], P = 0.93) and adjusted (1.10 [0.82-1.41], P = 0.62) analysis. Furthermore, no significant associations between baseline PPI use and PFS were identified on univariable (0.96 [0.76-1.21], P = 0.73) and adjusted (1.11 [0.86-1.44], P = 0.41) analysis.

CONCLUSION

In a large high-quality dataset, PPI use was not observed to compromise the survival outcomes of advanced HCC patients initiated on sorafenib.

Impact of Use of Gastric-Acid Suppressants and Oral Anti-Cancer Agents on Survival Outcomes: A Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis to evaluate the role of gastric acid suppressant use on outcomes of tyrosine kinase inhibitors (TKIs) and oral chemotherapy. We identified all research evaluating the effect of GAS (gastric acid suppressants) use on patients receiving oral chemotherapy or TKIs for solid tumors. The pooled hazard ratios (HRs) and 95% confidence interval (95%CI) for overall survival (OS) and progression-free survival (PFS) were calculated with a fixed-effects or a random effects model. The study population included n = 16 retrospective studies and 372,418 patients. The series concerned gastrointestinal tract tumors (n = 5 studies), renal cell carcinomas (RCC, n = 3 studies), non-small cell lung cancers (NSCLC, n = 5 studies), and soft tissue sarcomas or mixed histologies solid tumors in n = 3 studies. The pooled HRs for OS and PFS were 1.31 (95%CI: 1.20-1.43; p < 0.01) and 1.3 (95%CI 1.07-1.57; p < 0.01) for GAS and no GAS users, respectively. Only studies of EGFR (epidermal growth factor receptor) mutated NSCLC patients receiving TKIs and those with colorectal cancer receiving oral chemotherapy showed a significant correlation between GAS and poor survival. Our study supports the evidence of a possible negative impact of concomitant GAS therapy on survival outcomes of patients receiving oral anti-cancer drugs.

Sorafenib administered using a high-dose, pulsatile regimen in patients with advanced solid malignancies: a phase I exposure escalation study

Background

(Pre)clinical evidence is accumulating that intermittent exposure to increased doses of protein kinase inhibitors may improve their treatment benefit. In this phase I trial, the safety of high-dose, pulsatile sorafenib was studied.

Patients and methods

High-dose sorafenib was administered once weekly in exposure escalation cohorts according to a 3 + 3 design. Drug monitoring was performed in weeks 1–3 and doses were adjusted to achieve a predefined target plasma area under the curve (AUC)(0–12 h). The effect of low gastric pH on improving sorafenib exposure was investigated by intake of the acidic beverage cola.

Results

Seventeen patients with advanced malignancies without standard treatment options were included. Once weekly, high-dose sorafenib exposure was escalated up to a target AUC(0–12 h) of 125–150 mg/L/h, achieving a twofold higher C_max compared to standard continuous dosing. Dose-limiting toxicity was observed in three patients: grade 3 duodenal perforation (2800 mg sorafenib), grade 5 multiorgan failure (2800 mg sorafenib) and grade 5 biliary tract perforation (3600 mg sorafenib). The mean difference between observed and target AUC(0–12 h) was 45% (SD ± 56%) in week 1 using a fixed starting dose of sorafenib compared to 2% (SD ± 32%) in week 3 as a result of drug monitoring (P = 0.06). Dissolving sorafenib in cola, instead of water, did not improve sorafenib exposure. Clinical benefit with stable disease as the best response was observed in two patients.

Conclusion

Treatment with high-dose, once weekly sorafenib administration resulted in dose-limiting toxicity precluding dose escalation above the exposure cohort of 125–150 mg/L/h. Drug monitoring was a successful strategy to pursue a target exposure.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04065-5) contains supplementary material, which is available to authorized users.

[Proton pump inhibitors and cancers: A hazardous association?]

Proton pump inhibitors, a major progress in gastro-enterology, are globally among the most widely prescribed drugs. But, due to their strong gastric acid inhibition, they can be responsible for side effects, particularly in cancer patients. They are involved in renal function impairment, bone fractures, digestive bacterial overgrowth, particularlyclostridium difficile infections, anemia and hypomagnesemia. Long term use can increase the risks of gastric, pancreatic and liver cancers. They decrease absorption of weak bases drugs, particularly tyrosine kinase inhibitors and capecitabine and are responsible for a poorer prognosis if taken concomitantly with erlotinib, gefitinib and pazopanib. Modification of cyclin dependent kinases is also possible as well as decrease of efficacy of immune check point inhibitors (microbiome modifications). Absoption and efficacy of capecitabine seem also poorer with negative prognosis effect on treatment of gastric and colon cancer. Their long term use, particularly in cancer patients, should probably be avoided.

Optimizing treatment of renal cell carcinoma with VEGFR-TKIs: a comparison of clinical pharmacology and drug-drug interactions of anti-angiogenic drugs

Anti-angiogenic treatment is an important option that has changed the therapeutic landscape in various tumors, particularly in patients affected by renal cell carcinoma (RCC). Agents that block signaling pathways governing tumor angiogenesis have raised high expectations among clinicians. Vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) comprise a heterogeneous class of drugs with distinct pharmacological profiles, including potency, selectivity, pharmacokinetics and drug-drug interactions. Among them, tivozanib is one of the last TKIs introduced in the clinical practice; this drug selectively targets VEGFRs, it is characterized by a favorable pharmacokinetics and safety profile and has been approved as first-line treatment for patients with metastatic RCC (mRCC). In this article, we describe the clinical pharmacology of selected VEGFR-TKIs used for the treatment of mRCC, highlighting the relevant differences; moreover we aim to define the main pharmacologic characteristics of these drug.

Association between clinically relevant toxicities of pazopanib and sunitinib and the use of weak CYP3A4 and P-gp inhibitors

PURPOSE

Sunitinib and pazopanib, two tyrosine kinase inhibitors (TKI), may be targets of potential pharmacokinetic drug-drug interactions (P-PK-DDIs). While strong cytochrome P4503A (CYP3A4) inhibitors or inducers should cause a clinically relevant modification in plasma TKI concentrations, the effect of weak inhibitors is unknown. The objective of this study was to evaluate the association between weak P-PK-DDI and clinically relevant toxicity in real life.

PATIENTS AND METHODS

This was a single-center retrospective study including patients treated with sunitinib or pazopanib for any malignancies, for whom a PK-DDI analysis was performed before starting TKI. The primary endpoint was the correlation between P-PK-DDIs and a dose decrease after 1 month of treatment. The secondary endpoint was the correlation between PK-DDIs and drug withdrawal due to toxicity.

RESULTS

Seventy-six patients were assessed. A P-PK-DDI with weak CYP3A4 or P-gp inhibition was found in 14 patients. In patients with P-PK-DDI or without, the dose was reduced during the first month in 57.1% and 17.7% (p = 0.003) and the drug withdrawn in 42.8% and 11.3% (p = 0.011), respectively. In multivariate analysis, a significant correlation was found between P-PK-DDI (CYP3A4 and P-gp inhibitors) and dose reduction, and between drug withdrawal and PK-DDI (CYP3A4 inhibitors).

CONCLUSION

P-PK-DDI was correlated with dose reduction and drug withdrawal due to toxicity. The causality of this relationship warrants to be assessed; therefore, therapeutic drug monitoring is necessary in patients treated with TKI.

Effect of Acid-Suppressive Strategies on Pazopanib Efficacy in Patients With Soft-Tissue Sarcoma

Pazopanib (PAZ), a tyrosine kinase inhibitor used in the treatment of soft tissue sarcoma (STS), should not be administered with acid-suppressive medications (ASMs) due to decreased drug solubility. Common practice for patients requiring ASM with PAZ is to separate administration by 12 hours; however, there is little real-world evidence describing clinical outcomes using this strategy. The aim of this study was to determine whether concomitant ASM impacted efficacy and adverse event rates in patients with STS receiving PAZ. Medical records were retrospectively reviewed for patients with STS who received PAZ from June 2011 to July 2017. Patients were stratified into two groups, PAZ with or without ASM (PAZ + ASM or PAZ only). The primary objective was to determine whether progression-free survival (PFS) differed between groups. Secondary objectives were to determine overall survival (OS) and occurrence of grade 3/4 toxicities. Ninety-one patients were included in the study, 42 patients in the PAZ + ASM group and 49 in the PAZ only group. Median PFS was significantly shorter in the PAZ + ASM group than the PAZ only group (5.3 vs. 6.7 months). The PAZ + ASM group also had a 74% higher relative risk of progression or death than the PAZ only group, but there was no difference in OS. Regarding adverse events, the PAZ + ASM group trended toward lower levels of grade 3/4 hypertension (19% vs. 37%). These results suggest that ASM should be avoided in patients with STS receiving PAZ. Larger studies are needed to further elucidate the impact of ASM use with PAZ in clinical practice.