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

Proton Pump Inhibitors Worsen Colorectal Cancer Outcomes in Patients Treated with Bevacizumab

BACKGROUND

Approximately one-third of patients with advanced colorectal cancer (CRC) and treated with bevacizumab are prescribed proton pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs). However, there is limited data on the effects of PPIs and H2RAs in these patients. To investigate the oncological outcomes of PPI and H2RA use in CRC patients treated with bevacizumab, we performed a retrospective cohort study using the Taiwan National Health Insurance Research Database and Taiwan Cancer Registry Database from 2005 to 2020.

METHODS

In CRC patients treated with bevacizumab, the PPI users and H2RA users were matched with patients without acid-reducing agents (ARAs) by 1:4 propensity score matching. PPI users and H2RA users were matched with propensity scoring in a 1:1 ratio. We divided patients into 4 cumulative PPI dosage levels to assess the dose-response relationship. The primary endpoints were 5-year overall survival and cancer-specific survival.

RESULTS

Compared with ARA non-users, both H2RA users and PPI users were associated with reduced overall survival. PPI users were associated with more significant negative effects on overall survival. Compared with H2RA users, PPI users were associated with lower 5-year overall survival (aHR: 1.19, 95% CI: 1.09-1.31) and cancer-specific survival (aHR: 1.20, 95% CI: 1.09-1.31). A similar dose-response relationship was observed for PPI users in terms of 5-year overall survival and cancer-specific overall survival.

CONCLUSIONS

Compared to H2AR use, PPI use was associated with dose-dependent poorer oncological outcomes in metastatic CRC patients treated with bevacizumab.

The Effect of Concomitant Administration of Proton Pump Inhibitors on the Pharmacokinetics of CDK4/6 Inhibitors in Rats: Implications for the Evaluation of Hepatic and Transporter-Mediated Drug-Drug Interactions

BACKGROUND AND OBJECTIVES

Numerous clinical concerns have been expressed regarding the potential worsening of cyclin-dependent kinase 4/6 inhibitor effects in breast cancer patients because of co-administration of proton pump inhibitors. Hence, this study evaluated the effects of proton pump inhibitors on the pharmacokinetics of palbociclib and ribociclib in terms of  cytochrome P450 (CYP) 3A4 and P-glycoprotein involvement.

METHODS

The effects of omeprazole and rabeprazole on drug metabolism and efflux of these drugs were investigated using molecular docking, metabolic stability assay in rat liver microsomes, human recombinant CYP3A4 (rCYP3A4) enzymes, and Caco-2 cell monolayers, and in vivo pharmacokinetics with omeprazole and rabeprazole in (5 and 10 mg/kg) 30 min and 7 days before orally dosing palbociclib and ribociclib (10 mg/kg).

RESULTS

Omeprazole and rabeprazole inhibited CYP3A4 enzyme activity in rCYP3A4 baculosomes with a 50-60% inhibition at 30 μM. Additionally, both omeprazole and rabeprazole (10 µm) significantly reduced the P-glycoprotein-mediated drug efflux of palbociclib and ribociclib. The 7-day pretreatment of omeprazole at a dose of 10 mg/kg resulted in 24% and 26% reductions in palbociclib's mean maximum plasma concentration) Cmax and area under the plasma concentration-time curve (AUC0-24 h), respectively. Palbociclib's pharmacokinetics were not significantly altered by the pretreatment with rabeprazole; however, ribociclib pharmacokinetics exhibited an 83.94% increase in AUC0-24 h.

CONCLUSION

The findings indicate that long-term treatment with therapeutic doses of both omeprazole and rabeprazole can alter the pharmacokinetics of palbociclib and ribociclib. The co-administration of rabeprazole may alter the pharmacokinetics of palbociclib and ribociclib via CYP enzyme and P-glycoprotein inhibition.

Estimation of CDK inhibitors by RP-HPLC: application for pharmacokinetic interactions studies with PPIs

Background: The study investigated pharmacokinetic interactions between palbociclib and ribociclib with proton pump inhibitors (PPIs) using the reverse-phase high-performance liquid chromatography (RP-HPLC) method.Methods: Developed RP-HPLC method quantified palbociclib and ribociclib in biological matrices. In vitro metabolic stability assays and in vivo studies in rats evaluated effect of omeprazole and esomeprazole on pharmacokinetics of palbociclib and ribociclib.Results: The RP-HPLC method was sensitive, accurate and linear. Esomeprazole and omeprazole decreased metabolic clearance of palbociclib and ribociclib by several folds. In vivo, esomeprazole elevated Cmax of palbociclib and ribociclib by 90.1% and 86.4%, whereas omeprazole reduced it by 32.0% and 16.8%, respectively.Conclusion: The RP-HPLC method was used to analyze in vitro and in vivo samples. Long-term treatment with PPIs affects pharmacokinetics of palbociclib and ribociclib, necessitating optimal chemotherapy regimen.

Playing Hide-and-Seek with Tyrosine Kinase Inhibitors: Can We Overcome Administration Challenges?

Tyrosine kinase inhibitors (TKIs) have demonstrated significant efficacy against various types of cancers through molecular targeting mechanisms. Over the past 22 years, more than 100 TKIs have been approved for the treatment of various types of cancer indicating the significant progress achieved in this research area. Despite having significant efficacy and ability to target multiple pathways, TKIs administration is associated with challenges. There are reported inconsistencies between observed food effect and labeling administration, challenges of concomitant administration with acid-reducing agents (ARA), pill burden and dosing frequency. In this context, the objective of present review is to visit administration challenges of TKIs and effective ways to tackle them. We have gathered data of 94 TKIs approved in between 2000 and 2022 with respect to food effect, ARA impact, administration schemes (food and PPI restrictions), number of pills per day and administration frequency. Further, trend analysis has been performed to identify inconsistencies in the labeling with respect to observed food effect, molecules exhibiting ARA impact, in order to identify solutions to remove these restrictions through novel formulation approaches. Additionally, opportunities to reduce number of pills per day and dosing frequency for better patient compliance were suggested using innovative formulation interventions. Finally, utility of physiologically based pharmacokinetic modeling (PBPK) for rationale formulation development was discussed with literature reported examples. Overall, this review can act as a ready-to-use-guide for the formulation, biopharmaceutics scientists and medical oncologists to identify opportunities for innovation for TKIs.

Sodium citrate buffer improves pazopanib solubility and absorption in gastric acid-suppressed rat model

Pazopanib exhibits pH-dependent solubility and its absorption depends primarily on the stomach pH. Significant decrease of pazopanib absorption by coadministration with proton pump inhibitors in clinical situation need to be overcome. Thus, the purpose of this study is firstly to investigate the effect of acidic beverages and sodium citrate buffer on the solubility of pazopanib and secondly to examine the effect of sodium citrate buffer on pazopanib absorption in a rat model with esomeprazole-mediated gastric acid suppression. Pazopanib solubility decreased with increasing pH of sodium citrate buffer in vitro. Interestingly, its solubility in some acidic beverages was significantly lower than that in sodium citrate buffer of the same pH. The AUC0-24h of pazopanib administered in tap water to rats treated with esomeprazole (ESP rats) was 66 % lower than that in the control rats treated with saline. However, AUC0-24h was 4.8 times higher in ESP rats that received pazopanib with sodium citrate buffer (pH 2.3) compared to ESP rats that received pazopanib with tap water. Our results indicate that the drug-drug interactions between pazopanib and proton pump inhibitors can be overcome, at least in part, by suspending pazopanib in sodium citrate buffer.

Association of proton pump inhibitor use with survival and adverse effects outcomes in patients with multiple myeloma: pooled analysis of three clinical trials

Proton pump inhibitors (PPIs) are commonly used in cancer patients, but their impact on treatment outcomes in multiple myeloma (MM) patients remains unclear. This study investigated the association of PPI use with survival and adverse effects in MM patients across three randomized-control trials initiating daratumumab, lenalidomide, or bortezomib combination treatments. Cox proportional hazard analysis and logistic regression were employed to assess the associations with treatment outcomes, while adjusting for age, sex, weight, MM international staging system stage, ECOG-performance status, comorbidity count, and presence of gastrointestinal disorders. Pooled data involving 1804 patients revealed that 557 (32%) used PPIs at baseline. PPI use was independently associated with worse overall survival (adjusted HR [95% CI] 1.32 [1.08-1.62], P = 0.007) and grade ≥ 3 adverse events (adjusted OR [95% CI] 1.39 [1.03-1.88], P = 0.030). However, the association with progression-free survival did not reach statistical significance (adjusted HR [95% CI] 1.14 [0.97-1.33], P = 0.112). Findings were consistent across trials and treatment arms. PPI use was identified as a negative prognostic factor in MM patients, potentially enhancing clinical decisions regarding its use. Further research is needed to fully comprehend the impacts and safety of PPI use in MM patients.

Clinical impact of proton pump inhibitors and other co-medications on advanced melanoma patients treated with BRAF/MEK inhibitors

PURPOSE

While several studies reported the influence of co-medications on immune checkpoint therapy and chemotherapy, it remains poorly studied with targeted therapy. Targeted therapies inhibiting BRAF and MEK had significantly improved management of advanced melanoma with BRAFV600 mutation over the last decade, we aimed to investigate the possible influence of co-mediations on the efficacy and toxicity of these targeted therapies (TT).

METHODS

We conducted an observational study identifying patients with advanced melanoma treated with BRAF/MEK inhibitors between 2013 and 2020 in the Bordeaux University Hospital. Co-medications given within 1 month before until 3 months after the initiation of targeted therapy were recorded and classified by their mechanism or by their metabolism. Survival data were analyzed with univariable and multivariable cox regression and the combined effect of multiple factors was evaluated using a factor analysis of mixed data (FAMD). The impact of co-medications on toxicity related to TT was also assessed.

RESULTS

A total of 192 patients were included. Although several co-medications were associated with significantly shorter overall survival (OS) and/or progression-free survival (PFS), PPIs was the only co-medication with a significant impact in multivariable analysis considering all co-medications and specific prognostic factors. Co-medications did not influence the risk, type, or timing of TT-related toxicity. Additional FAMD revealed the impact of each factor on the oncological outcomes. In a subgroup of patients, residual plasma TT concentration was available and did not differ between PPIs users and non-users.

CONCLUSION

Co-medications, especially PPIs, must be carefully assessed at the time of TT initiation.

The impact of antibiotic and proton pump inhibitor use at the time of adjuvant platinum-based chemotherapy on survival in patients with endometrial cancer

OBJECTIVE

We sought to assess the impact of antibiotic (ABX) and proton-pump inhibitor (PPI) use on progression-free (PFS) and overall survival (OS) in patients treated with adjuvant platinum-based chemotherapy (PC) for endometrial cancer (EC).

METHODS

A retrospective, single-institution cohort study of EC patients treated with ≥four cycles of adjuvant PC following surgical staging from 2014 to 2020. Demographics and clinicopathologic features, including ABX and PPI use, were compared using χ2 and Fisher's exact tests. Univariate and multivariable analyses were performed, and survival outcomes were compared using the log-rank test.

RESULTS

Of 325 patients, 95 (29%) received ABX, and 80 (24.6%) received PPI. ABX were associated with decreased 3-year PFS (49.9% vs. 66%; p = 0.0237) but not 3-year OS (68.9% vs. 79.9%; p = 0.0649). ABX targeting gram-positive bacteria were associated with decreased 3-year PFS (21.2% vs. 66.0% vs. 55.4%; p = 0.0038) and 3-year OS (36.5% vs. 79.9% vs. 75.6%; p = 0.0014) compared to no ABX and other ABX, respectively. PPI use was associated with decreased 3-year PFS (46.9% vs. 66.0%; p = 0.0001) and 3-year OS (60.7% vs. 81.9%; p = 0.0041) compared to no PPI. On multivariable regression analysis controlling for confounders including stage, histology, grade, radiation, and co-morbidities, PPI use was independently associated with worse PFS (HR 1.96, 95% CI 1.25-3.08; p = 0.0041) and OS (HR 2.06, 95% CI 1.01-4.18, p = 0.04).

CONCLUSION

In this retrospective cohort study, we demonstrate that PPI use is independently associated with worse PFS and OS in patients with EC treated with PC. ABX use was associated with worse PFS on univariate analysis only. There is an unmet need to understand how PPI, ABX, and, potentially, the microbiome impact the effectiveness of chemotherapy in EC patients.

Immune checkpoint inhibitors and their interaction with proton pump inhibitors-related interstitial nephritis

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy and outcomes, leading to an expanding use in millions of patients worldwide. However, they can cause a spectrum of immune-related adverse events (irAEs). Essentially, any organs can be affected by irAEs, which have emerged as therapy-limiting side effects. In the kidneys, ICI-associated acute interstitial nephritis (ICI-AIN) leads to acute kidney injury (AKI) in 2%-5% of patients on ICI therapy. AKI associated with ICI therapy pathologically presents with AIN in nearly 90% of the cases, but the pathophysiology of ICI-AIN remains to be defined. The generation of autoreactive T cells in patients receiving AIN-inducible drugs, such as proton pump inhibitors (PPIs), is one of the leading theories, supported by a higher incidence of ICI-AIN in patients on these AIN-inducible drugs. In this review, we will discuss our understanding of the incidence, potential pathophysiological mechanisms, clinical presentations, risk factors, diagnosis, and management of PPI-related AIN and its interaction with ICI therapy.

The Gut Microbiome from a Biomarker to a Novel Therapeutic Strategy for Immunotherapy Response in Patients with Lung Cancer

The gastrointestinal microbiome has been shown to play a key role in determining the responses to cancer immunotherapy, including immune checkpoint inhibitor (ICI) therapy and CAR-T. In patients with non-small cell lung cancer (NSCLC), increasing evidence suggests that a microbiome composition signature is associated with clinical response to ICIs as well as with the development of immune-related adverse events. In support of this, antibiotic (ATB)-related dysbiosis has been consistently linked with the deleterious impact of ICI response, shortening the overall survival (OS) among patients on ATBs prior to ICI initiation. In parallel, several preclinical experiments have unravelled various strategies using probiotics, prebiotics, diet, and fecal microbiota transplantation as new therapeutic tools to beneficially shift the microbiome and enhance ICI efficacy. These approaches are currently being evaluated in clinical trials and have achieved encouraging preliminary results. In this article, we reviewed the recent studies on the gut microbiome as a potential biomarker and an adjuvant therapy to ICIs in NSCLC patients.

Effects of vonoprazan and proton pump inhibitors on the efficacy of bevacizumab: a multicentre retrospective study

Gastric acid secretion inhibitors such as proton pump inhibitors (PPIs) and vonoprazan may change the duration of treatment with bevacizumab, a vascular endothelial growth factor (VEGF) inhibitor, for cancer. However, there are no data on this prolongation effect. Here, we aimed to determine whether the use of PPIs or vonoprazan in patients with cancer receiving bevacizumab affected the duration of bevacizumab treatment. This observational study was conducted at two national university hospitals in Japan and involved 222 patients using oral PPIs (N = 190) or vonoprazan (N = 32) at the start of bevacizumab treatment between January 2015 and December 2018. Patients who received only one course of bevacizumab were excluded. The primary endpoint was the duration of bevacizumab treatment. The duration of bevacizumab treatment varied significantly between the PPI and vonoprazan groups. For cancer types other than colorectal cancer (breast, lung, brain, and ovarian cancers), the median duration of treatment was 217 days (p < 0.05) and was longer in the vonoprazan group than in the PPI group. However, for colorectal cancer, the median duration of bevacizumab treatment was 147 days longer in the PPI group than in the vonoprazan group. Selection of appropriate gastric acid secretion inhibitors may improve the therapeutic efficacy of anti-VEGF drugs, including bevacizumab. Oestrogen is a key regulator of this effect and may be responsible for the varying association between PPI or vonoprazan administration and the difference in bevacizumab treatment duration between colon cancer and other cancer types.

A new method to quantify the effect of co-medication on the efficacy of abiraterone in metastatic castration-resistant prostate cancer patients

Background and Objective: Patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA) have co-morbidities treated with different drugs. The aim was to quantify the potential effect of co-medications on AA treatment duration (TD) and overall survival (OS). Methods: A new parameter, called "individual drug score" (IDS) was calculated by summing the "drug score"-s (DS) of all co-medications for each patient. The DS was determined by quantifying the effect of a given co-drug on enzymes involved in steroidogenesis and metabolism of AA. The correlation between log (IDS) and TD was tested by non-linear curve fit. Kaplan-Meier method and multivariate Cox regression was used for analysis of TD and OS. Results: The IDS and TD of AA+prednisolone showed a dose-response correlation (n = 166). Patients with high IDS had significantly longer TD and OS (p <0.001). In multivariate analysis IDS proved to be an independent marker of TD and OS. The same analysis was performed in a separate group of 81 patients receiving AA+dexamethasone treatment. The previously observed relationships were observed again between IDS and TD or OS. After combining the AA+prednisolone and AA+dexamethasone groups, analysis of the IDS composition showed that patients in the high IDS group not only used more drugs (p <0.001), but their drugs also had a higher mean DS (p = 0.001). Conclusion: The more co-drugs with high DS, the longer the duration of AA treatment and OS, emphasizing the need for careful co-medication planning in patients with mCRPC treated with AA. It is recommended that, where possible, co-medication should be modified to minimize the number of drugs with negative DS and increase the number of drugs with high DS. Our new model can presumably be adapted to other drugs and other cancer types (or other diseases).

Comprehensive clinical pharmacology characterization of AZD4635 in healthy participants to support dosing considerations

AIMS

Two phase 1 studies characterized the oral bioavailability of AZD4635 (potential anticancer therapy) and factors that may influence its pharmacokinetics (PKs; food, smoking, proton-pump inhibitors [PPIs] and CYP1A2 inhibitors) to support continued clinical development of AZD4635.

METHODS

Study 1 (comparative PK study; nonsmokers) consists of Part A and Part B. Participants (fasted) in Part A were administered 50 mg of AZD4635 either as nanosuspension or capsule. In Part B, these participants were administered a 50-mg capsule either following a high-fat meal or with a PPI in the fasted state. In Study 2 (CYP1A2 mediated drug-drug interaction study), a 25-mg AZD4635 capsule was administered to smokers and nonsmokers (fasted) with or without 100 mg of fluvoxamine.

RESULTS

In Study 1 (N = 21), AZD4635 exposure was comparable between the capsule and nanosuspension. The high-fat meal produced a 12% decrease in AUCinf , a ≥50% reduction in Cmax and delayed absorption (Tmax : 4.0 h vs 1.5 h) for the capsule. The PPI did not affect the oral bioavailability of the AZD4635 capsule. In Study 2 (N = 28), AZD4635 + fluvoxamine (compared with AZD4635 alone) produced ~5-fold increases in AUCinf , 2-fold increases in Cmax and prolonged AZD4635 elimination half-life in smokers (22.7 vs 9.0 h) and nonsmokers (22.4 vs 9.2 h). All treatment regimens were well tolerated. The most common adverse events included dizziness, nausea and headache.

CONCLUSIONS

The high-fat meal reduced the rate but not the extent of AZD4635 absorption. The effect of gastric pH on AZD4635 was minimal. Smoking had no effect on the exposure (Cmax and AUCinf ) of AZD4635, while fluvoxamine increased AZD4635 Cmax and total exposure. No new safety concerns were identified.

The Impact of Concomitant Proton Pump Inhibitors Therapy on Clinical Outcome of Cancer Patients Treated With Immune Checkpoint Inhibitors: A Meta-analysis

BACKGROUND

In patients with advanced cancer receiving immune checkpoint inhibitors (ICIs) therapy, there are conflict perspectives about the influence of concomitant use of proton pump inhibitors (PPIs). We are aimed at exploring the influence of concomitant PPIs exposure on clinical outcome among cancer patients receiving ICIs treatment.

METHODS

We searched relevant literatures in PubMed, EMBASE, and the Cochrane Library without language restrictions. We extracted the data from selected studies and calculated the pooled hazard ratios (HRs) with 95% CIs through professional software for overall survival and progression-free survival among cancer patients undergoing ICIs therapy exposed to PPIs.

RESULTS

Fourteen studies including 6716 advanced cancer patients receiving ICIs treatment were appropriate for analysis judging by pre-set inclusion and exclusion criteria. The result indicated that concomitant PPIs exposure was significantly related to shorter overall survival (HR=1.388; 95% CI: 1.278-1.498, P <0.001) and progression-free survival (HR=1.285; 95% CI: 1.193-1.384, P <0.001) among multiple cancer patients receiving ICIs therapy.

CONCLUSIONS

Our meta-analysis showed that concomitant PPIs exposure had an adverse impact on clinical outcome among patients receiving ICIs therapy. Clinical oncologists must be cautious of PPIs delivery during ICIs treatment.

Clinical impact of tetracyclines and/or proton pump inhibitors on the efficacy of epidermal growth factor receptor inhibitors in non-small cell lung cancer: a retrospective cohort study

BACKGROUND

This retrospective cohort study examined the impact of tetracyclines (TCs) and proton pump inhibitors (PPIs) alone or in combination on the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small cell lung cancer (NSCLC).

METHODS

Patients with NSCLC treated with gefitinib or erlotinib for at least 1 week between January 2009 and October 2021 were enrolled and divided into four groups based on the presence/absence of TC and/or PPI in the therapeutic regimen: TC-/PPI-, TC + /PPI-, TC-/PPI + , TC + /PPI + . Progression-free survival (PFS) and overall survival (OS) were the primary and secondary endpoints, respectively.

RESULTS

The estimated median PFS and OS of 347 included patients with NSCLC were 8.57 (95% confidence interval [CI]: 7.66-9.48) months and 13.10 (95% CI: 11.03-15.17) months, respectively. Co-administration of EGFR-TKIs with PPIs decreased the PFS and OS, while that with TCs improved the PFS and OS. However, the concomitant use of EGFR-TKIs, TCs, and PPIs yielded survival rates similar to that of EGFR-TKI therapy alone.

CONCLUSIONS

The administration of EGFR-TKIs with other drugs poses a challenge in managing patients with NSCLC. Therefore, reassessing the indications and necessity of TC or PPI therapy is essential for patients receiving erlotinib or gefitinib. The benefits and risks of possible discontinuation due to the clinical relevance of this interaction should be considered.

The concomitant use of proton pump inhibitors and BRAF/MEK inhibitors in metastatic melanoma

BACKGROUND

Proton-pump inhibitors (PPIs) are commonly used by patients with cancer, although they could reduce the absorption of oral anticancer targeted therapies. The US Food and Drug Administration states that the effect of PPIs on the efficacy of dabrafenib use by patients with metastatic melanoma is unknown. As a precautionary measure, the European Society for Medical Oncology recommends avoiding PPIs for patients receiving dabrafenib.

OBJECTIVES

To determine the effect of the concomitant use of PPIs and BRAF/MEK inhibitors in patients with metastatic melanoma.

METHODS

Patients with advanced melanoma receiving BRAF/MEK inhibitors as first-line treatments between 2015 and 2017 in France were selected using the French National Health Insurance database. We compared time-to-treatment discontinuation (TTD) and overall survival (OS) according to concomitant PPI exposure. We balanced the baseline characteristics of patients exposed and nonexposed to PPIs using an overlap weighting method based on a propensity score.

RESULTS

The metastatic melanoma cohort comprised 1028 patients receiving BRAF/MEK inhibitors, including 361 (35.1%) patients using PPIs. PPI users had more comorbidities and a more severe metastatic disease. After having equally distributed metastatic sites and comorbidities across patients exposed and nonexposed to PPIs, concomitant PPI use was not associated with shorter TTD [weighted hazard ratio (wHR) 1.03, 95% confidence interval (CI) 0.86-1.24] or OS (wHR 1.11, 95% CI 0.88-1.39). Consistent results were observed when restricting the population to patients receiving dabrafenib, or when narrowing exposure to PPIs with stronger inhibition of cytochromes.

CONCLUSIONS

In a population-based cohort of patients with advanced melanoma, the concomitant use of PPIs and BRAF/MEK inhibitors was not associated with worse outcome.

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 Prime and Integral Cause of Cancer in the Post-Warburg Era

Back to beginnings. A century ago, Otto Warburg published that aerobic glycolysis and the respiratory impairment of cells were the prime cause of cancer, a phenomenon that since then has been known as "the Warburg effect". In his early studies, Warburg looked at the effects of hydrogen ions (H+), on glycolysis in anaerobic conditions, as well as of bicarbonate and glucose. He found that gassing with CO2 led to the acidification of the solutions, resulting in decreased rates of glycolysis. It appears that Warburg first interpreted the role of pH on glycolysis as a secondary phenomenon, a side effect that was there just to compensate for the effect of bicarbonate. However, later on, while talking about glycolysis in a seminar at the Rockefeller Foundation, he said: "Special attention should be drawn to the remarkable influence of the bicarbonate…". Departing from the very beginnings of this metabolic cancer research in the 1920s, our perspective advances an analytic as well as the synthetic approach to the new "pH-related paradigm of cancer", while at the same time addressing the most fundamental and recent changing concepts in cancer metabolic etiology and its potential therapeutic implications.

The Mammalian Cysteine Protease Legumain in Health and Disease

The cysteine protease legumain (also known as asparaginyl endopeptidase or δ-secretase) is the only known mammalian asparaginyl endopeptidase and is primarily localized to the endolysosomal system, although it is also found extracellularly as a secreted protein. Legumain is involved in the regulation of diverse biological processes and tissue homeostasis, and in the pathogenesis of various malignant and nonmalignant diseases. In addition to its proteolytic activity that leads to the degradation or activation of different substrates, legumain has also been shown to have a nonproteolytic ligase function. This review summarizes the current knowledge about legumain functions in health and disease, including kidney homeostasis, hematopoietic homeostasis, bone remodeling, cardiovascular and cerebrovascular diseases, fibrosis, aging and senescence, neurodegenerative diseases and cancer. In addition, this review addresses the effects of some marketed drugs on legumain. Expanding our knowledge on legumain will delineate the importance of this enzyme in regulating physiological processes and disease conditions.

Pattern of Adverse Drug Reactions Associated with the Use of Anticancer Drugs in an Oncology-Based Hospital of Nepal

Introduction

Adverse drug reactions (ADRs) are among the leading causes of morbidity and mortality worldwide. ADRs of anticancer drugs are ubiquitous. However, in Nepal, studies on chemotherapy-induced ADRs are scarce. Thus, this study aimed to assess the ADRs associated with the use of anticancer drugs and their management along with causality assessment and severity of ADRs.

Methods

A prospective cross-sectional observational and single-center study was conducted at Bhaktapur Cancer Hospital, Nepal, for 6 months. All the patients who fulfilled the study criteria were analyzed to identify ADRs occurring daily. In addition, all collected data were recorded and analyzed using descriptive statistics.

Results

A total of 861 ADRs were detected among 102 cancer patients. The mean ± S.D. age of the patients was 49.93 ± 14.27 years, and each enrolled patient experienced one or more ADRs with a mean ± S.D. of 8.44 ± 3.27. The common ADRs observed were fatigue, anorexia, alopecia, constipation, nausea, vomiting, and neuropathy. Cyclophosphamide, either alone or in combination with other chemotherapeutic agents, was responsible for most ADRs. According to Naranjo's causality assessment algorithm, most of the ADRs belonged to the probable (47.1%) category. Majority (54.9%) of the ADRs were moderate in their severity. Proton pump inhibitors, antiemetic, mouth gargle, protein powders, iron tablets, and multivitamin and mineral tablets were commonly used for ADR management.

Conclusions

The occurrence of chemotherapy-related ADRs in each enrolled patient is a crucial concern. The present study highlights the need for active monitoring of the patients to identify and manage ADRs promptly.

Protein tyrosine kinase inhibitor resistance in malignant tumors: molecular mechanisms and future perspective

Protein tyrosine kinases (PTKs) are a class of proteins with tyrosine kinase activity that phosphorylate tyrosine residues of critical molecules in signaling pathways. Their basal function is essential for maintaining normal cell growth and differentiation. However, aberrant activation of PTKs caused by various factors can deviate cell function from the expected trajectory to an abnormal growth state, leading to carcinogenesis. Inhibiting the aberrant PTK function could inhibit tumor growth. Therefore, tyrosine kinase inhibitors (TKIs), target-specific inhibitors of PTKs, have been used in treating malignant tumors and play a significant role in targeted therapy of cancer. Currently, drug resistance is the main reason for limiting TKIs efficacy of cancer. The increasing studies indicated that tumor microenvironment, cell death resistance, tumor metabolism, epigenetic modification and abnormal metabolism of TKIs were deeply involved in tumor development and TKI resistance, besides the abnormal activation of PTK-related signaling pathways involved in gene mutations. Accordingly, it is of great significance to study the underlying mechanisms of TKIs resistance and find solutions to reverse TKIs resistance for improving TKIs efficacy of cancer. Herein, we reviewed the drug resistance mechanisms of TKIs and the potential approaches to overcome TKI resistance, aiming to provide a theoretical basis for improving the efficacy of TKIs.

An Up-To-Date Investigation Into the Correlation Between Proton Pump Inhibitor Use and the Clinical Efficacy of Immune Checkpoint Inhibitors in Advanced Solid Cancers: A Systematic Review and Meta-Analysis

Background

Although immune checkpoint inhibitors (ICIs) have revolutionized the current anticancer therapies, a considerable proportion of patients are found to hardly benefit from these drugs. Accumulating studies have demonstrated that concomitant proton pump inhibitor (PPI) use may affect the clinical efficacy of ICIs; however, their results are inconsistent. In this study, based on updated evidence, we aimed to perform a meta-analysis to clarify the prognostic significance of PPI use in advanced solid cancer patients receiving ICI therapy.

Methods

Eligible literature was searched using PubMed, Cochrane Library, Web of Science, EMBASE, and other network resources before July 2021. Clinical outcome was evaluated using overall survival (OS) and progression-free survival (PFS). The correlation of PPI use with OS or PFS was determined based on hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

A total of 17 studies enrolling 9,978 ICI-treated cancer patients were included in our meta-analysis. The global analysis demonstrated that PPI use was significantly correlated with worse OS [HR = 1.29 (1.10-1.50)] instead of PFS [HR = 1.19 (0.98-1.44)] in solid cancer patients receiving ICI therapy. In a subgroup analysis, the negative correlation of PPI use with ICI efficacy was significant in patients with non-small cell lung cancer [PFS, HR = 1.27 (1.10-1.47)] and urothelial carcinoma [OS, HR = 1.55 (1.31-1.84), PFS, HR = 1.52 (1.13-2.06)] and mixed cohorts containing multiple cancer types [OS, HR = 1.40 (1.16-1.69)], while an opposite result was observed in the PFS of patients with melanoma [HR = 0.48 (0.25-0.90)]. Moreover, the unfavorable prognostic impact of PPI use was also significant in patients over 65 years old [OS, HR = 1.28 (1.05-1.55), PFS, HR = 1.32 (1.12-1.56)] or those receiving anti-PD-1 [OS, HR = 1.37 (1.04-1.79)] or anti-PD-L1 therapies (OS, HR = 1.49 (1.30-1.69), PFS, HR = 1.34 (1.20-1.50). Finally, PPI use was significantly correlated with a worse prognosis in patients receiving PPIs 30 days before and/or after ICI initiation (OS, HR = 1.38 (1.18-1.62), PFS, HR = 1.23 (1.06-1.43)).

Conclusion

Although our global analysis revealed PPI use was not correlated with the PFS of ICI-treated patients, considering the results of our subgroup analysis, PPIs should be still cautiously used shortly before or during ICI therapy. Furthermore, more clinical validations and related mechanism investigations are of great necessity to clarify the clinical correlation of PPI use with ICI efficacy.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], PROSPERO [No. CRD42021243707].

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 Gastric Acid Suppressants on the Survival of Patients with Non-Small-Cell Lung Cancer Treated with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors: A Meta-Analysis

BACKGROUND

The influence of concomitant use of gastric acid suppressants (AS) on survival of patients with non-small-cell lung cancer (NSCLC) treated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is inconsistent according to previous studies. We performed a meta-analysis to evaluate the effect of additional AS in patients with NSCLC taking TKIs.

METHODS

Relevant observational studies were identified by a search of Medline, Embase, and Web of Science databases. Only studies with multivariate analyses were included. A random-effect model was used to combine the results.

RESULTS

Thirteen retrospective studies with 12259 patients were included. Pooled results showed that concomitant use of AS was associated with worse progression-free survival (PFS, adjusted hazard ratio (HR): 1.57, 95% confidence interval (CI): 1.31 to 1.89, P < 0.001; I ² = 65%) and overall survival (OS, adjusted HR: 1.38, 95% CI: 1.19 to 1.61, P < 0.001; I ² = 70%) in NSCLC patients taking TKIs. Sensitivity analysis limited to studies including NSCLC with EGFR mutation showed consistent results (HR for PFS: 1.53, P=0.003; HR for OS: 1.43, P=0.001). Subgroup analyses indicated that the association between concomitant use of AS and poor survival was not significantly affected by the category of AS used (proton pump inhibitors or histamine type-2 receptor antagonists) or the country of the study (Asian or non-Asian, P for subgroup analysis all >0.05).

CONCLUSIONS

Concomitant use of AS in patients with NSCLC taking TKIs may be associated with poor survival outcomes.

Carbonic Anhydrase IX Inhibitors as Candidates for Combination Therapy of Solid Tumors

Combination therapy is becoming imperative for the treatment of many cancers, as it provides a higher chance of avoiding drug resistance and tumor recurrence. Among the resistance-conferring factors, the tumor microenvironment plays a major role, and therefore, represents a viable target for adjuvant therapeutic agents. Thus, hypoxia and extracellular acidosis are known to select for the most aggressive and resilient phenotypes and build poorly responsive regions of the tumor mass. Carbonic anhydrase (CA, EC 4.2.1.1) IX isoform is a surficial zinc metalloenzyme that is proven to play a central role in regulating intra and extracellular pH, as well as modulating invasion and metastasis processes. With its strong association and distribution in various tumor tissues and well-known druggability, this protein holds great promise as a target to pharmacologically interfere with the tumor microenvironment by using drug combination regimens. In the present review, we summarized recent publications revealing the potential of CA IX inhibitors to intensify cancer chemotherapy and overcome drug resistance in preclinical settings.

In Vitro-In Silico Tools for Streamlined Development of Acalabrutinib Amorphous Solid Dispersion Tablets

Amorphous solid dispersion (ASD) dosage forms can improve the oral bioavailability of poorly water-soluble drugs, enabling the commercialization of new chemical entities and improving the efficacy and patient compliance of existing drugs. However, the development of robust, high-performing ASD dosage forms can be challenging, often requiring multiple formulation iterations, long timelines, and high cost. In a previous study, acalabrutinib/hydroxypropyl methylcellulose acetate succinate (HPMCAS)-H grade ASD tablets were shown to overcome the pH effect of commercially marketed Calquence in beagle dogs. This study describes the streamlined in vitro and in silico approach used to develop those ASD tablets. HPMCAS-H and -M grade polymers provided the longest acalabrutinib supersaturation sustainment in an initial screening study, and HPMCAS-H grade ASDs provided the highest in vitro area under the curve (AUC) in gastric to intestinal transfer dissolution tests at elevated gastric pH. In silico simulations of the HPMCAS-H ASD tablet and Calquence capsule provided good in vivo study prediction accuracy using a bottom–up approach (absolute average fold error of AUC_0-inf < 2). This streamlined approach combined an understanding of key drug, polymer, and gastrointestinal properties with in vitro and in silico tools to overcome the acalabrutinib pH effect without the need for reformulation or multiple studies, showing promise for reducing time and costs to develop ASD drug products.

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

Amorphous Solid Dispersion Tablets Overcome Acalabrutinib pH Effect in Dogs

Calquence^® (crystalline acalabrutinib), a commercially marketed tyrosine kinase inhibitor (TKI), exhibits significantly reduced oral exposure when taken with acid-reducing agents (ARAs) due to the low solubility of the weakly basic drug at elevated gastric pH. These drug-drug interactions (DDIs) negatively impact patient treatment and quality of life due to the strict dosing regimens required. In this study, reduced plasma drug exposure at high gastric pH was overcome using a spray-dried amorphous solid dispersion (ASD) comprising 50% acalabrutinib and 50% hydroxypropyl methylcellulose acetate succinate (HPMCAS, H grade) formulated as an immediate-release (IR) tablet. ASD tablets achieved similar area under the plasma drug concentration-time curve (AUC) at low and high gastric pH and outperformed Calquence capsules 2.4-fold at high gastric pH in beagle dogs. In vitro multicompartment dissolution testing conducted a priori to the in vivo study successfully predicted the improved formulation performance. In addition, ASD tablets were 60% smaller than Calquence capsules and demonstrated good laboratory-scale manufacturability, physical stability, and chemical stability. ASD dosage forms are attractive for improving patient compliance and the efficacy of acalabrutinib and other weakly basic drugs that have pH-dependent absorption.