Association of hypomagnesemia with inferior survival in a phase III, randomized study of cetuximab plus best supportive care versus best supportive care alone: NCIC CTG/AGITG CO.17

Epidermal Growth Factor Receptor Inhibitor-Induced Hypomagnesaemia: Is There a Best Replacement Strategy?

Monoclonal antibodies targeting the epidermal growth factor receptor (EGFRI), such as cetuximab and panitumumab, are commonly used systemic therapies for advanced colorectal and head and neck cancers. Hypomagnesaemia is a common side effect of these therapies and occurs in up to 30% of patients. Interruption of EGFR signalling in the distal convoluted tubule leads to inactivation of the transcellular transporter transient receptor potential channel melastatin member 6 and increased renal magnesium excretion. This paper describes the incidence, risk factors, and the emerging management options for EGFRI-induced hypomagnesaemia.

Drinking from the firehose - A clinician's perspective on the challenges of delivering biomarker-driven care in routine practice

Countless biomarkers continue to be identified and analysed in the modern era of omics focused research, with innumerable articles purporting clinical utility and bolstering optimism for truly personalised cancer care. While many commentaries have expounded on the complexities of biomarker development, validation and reporting, the monumental challenge of integrating this research into clinical practice has to date received little attention. The challenges are multitude; variable and sometimes contradictory findings across studies for individual biomarkers, a rapidly evolving landscape with new biomarkers continually being presented and tendency to examine each biomarker in isolation. Here, using examples from colorectal cancer, we explore the difficulties for the practicing clinician in interpreting and integrating novel biomarkers. Here, we present the '4Cs' to interrogate the biomarker literature, including analysis of the credibility, consistency, completeness and context of the biomarker research, and suggest a framework to frame the literature moving forward.

Disorders of Divalent Ions (Magnesium, Calcium, and Phosphorous) in Patients With Cancer

Disorders of the divalent ions (magnesium, calcium, and phosphorous) are frequently encountered in patients with cancer. Of these, hypomagnesemia, hypocalcemia, hypercalcemia, and hypophosphatemia are seen most commonly. These electrolyte disturbances may be related to the underlying malignancy or due to side effects of anticancer therapy. When caused by a paraneoplastic process, these abnormalities may portend a poor prognosis. Importantly, the development of severe electrolyte derangements may be associated with symptoms that negatively impact quality of life, preclude the administration of critical chemotherapeutic agents, or lead to life-threatening complications that require hospitalization and emergent treatment. In accordance, prompt recognition and treatment of these disorders is key to improving outcomes in patients living with cancer. This review will discuss selected derangements of the divalent ions seen in this population, with a focus on paraneoplastic and therapy-associated etiologies.

Predictive and prognostic value of magnesium serum level in FOLFIRI plus cetuximab or bevacizumab treated patients with stage IV colorectal cancer: results from the FIRE-3 (AIO KRK-0306) study

Magnesium wasting is a frequent side effect of epidermal growth factor receptor (EGFR)-antibody treatment as magnesium-absorption mechanisms are dependent on EGFR signaling. EGFR-inhibition results in decreased renal reabsorption. There is evidence that hypomagnesemia during cetuximab treatment correlates with response. The prognostic role of hypomagnesemia during bevacizumab treatment has not been studied yet. Here, we evaluate the prognostic value of hypomagnesemia in patients with metastatic colorectal cancer treated with FOLFIRI plus cetuximab or bevacizumab as first-line therapy. A total of 391 of 752 patients of the firstline irinotecan study population had magnesium levels measured at baseline and for the first three cycles (6 weeks) of treatment. Of those, 240 had Rat Sarkoma wildtype tumors. Overall hypomagnesemia was more common in the cetuximab compared to the bevacizumab arm (80 vs. 43%, P < 0.005). During therapy, magnesium showed a time-dependent decrease to 80% of baseline in the cetuximab and to 89% in the bevacizumab arm. Whereas magnesium continued to decrease over time in the cetuximab-treated patients, it remained stable in the bevacizumab-treated. Overall response rate (ORR) was associated with higher magnesium at week 6 (20.9 vs. 79.1%, P = 0.041). Bevacizumab-treated patients with magnesium levels below the median value at week 6 had a significantly longer progression-free survival (PFS; 11.7 vs. 9.9 months, P = 0.034; hazard ratio 0.73) and a trend towards longer overall survival (OS) (29.6 vs. 23.2 months, P = 0.089; hazard ratio 0.77). Hypomagnesemia at predefined time points and magnesium nadir had no significant effect on ORR, OS and PFS in the cetuximab arm. Our data show different magnesium kinetics in patients with metastatic colorectal cancer treated with cetuximab or bevacizumab. For patients treated with cetuximab, hypomagnesemia did not have an impact on response and survival. Hypomagnesemia might have a prognostic value in bevacizumab treatment.

Effective chemotherapy and targeted therapy supplemented with stereotactic radiotherapy of a patient with metastatic colon cancer following renal transplantation: a case report

Background

Previous studies have shown that patients who underwent renal transplantation were at a greater risk of developing malignancies. Due to advances in effective surgical techniques and immunosuppressive therapies, organ recipients live longer. Yet, there is insufficient information about the recommended type of therapy for colorectal cancer patients following transplantation. We describe the oncological treatment of a patient with renal transplantation, who presented with metastatic colon cancer 5 years after transplantation.

Case presentation

A 66-year-old Caucasian male patient, with hypertension, type 2 diabetes mellitus, paroxysmal atrial fibrillation, and renal failure underwent successful kidney transplantation in 2013. In April 2018, the adenocarcinoma of the sigmoid colon was found, and surgical resection was performed. The histological diagnosis was low-grade adenocarcinoma. Fluorodeoxyglucose positron emission tomography/computerized tomography scan showed a 2.5-cm metastasis in the VIIth segment of the liver and a metastatic paraaortical lymph node on the left. The clinical diagnosis was, therefore, metastatic (stage IV) sigmoid colon cancer (AJCC TNM system). The ongoing medications of the patient included immunosuppressive drugs and medication for his cardiovascular comorbidities. In July 2018, palliative cetuximab plus folinic acid–fluorouracil–irinotecan chemotherapeutic treatment was initiated, then cetuximab was substituted for panitumumab because of adverse events. In August 2018, the follow-up positron emission tomography/computerized tomography scan revealed stable disease. Because of side effects, the patient was unwilling to continue with the panitumumab plus folinic acid–fluorouracil–irinotecan treatment regimen. Therefore, the patient received 10× 5 Gy stereotactic body irradiation for his liver metastasis and mono-panitumumab therapy. By January 2019, the positron emission tomography/computerized tomography scan showed regression of the liver metastasis but a progression in the paraaortic lymph node. Therefore, 5× 8 Gy stereotactic irradiation was given to the paraaortic lesion. Meanwhile, the patient received altogether 16 cycles of panitumumab until June 2019, when complete remission was attained. In July 2019, the patient suffered a hemorrhagic stroke, probably due to his cardiovascular comorbidities, and died subsequently.

Conclusions

Since information is scarce regarding oncological treatment of patients following organ transplantation, data about their oncological treatment is essential. To our knowledge, this is the first case report to describe the successful chemotherapy and targeted therapy supplemented with stereotactic radiotherapy of a posttransplant patient with metastatic colorectal cancer.

Magnesium Absorption in Intestinal Cells: Evidence of Cross-Talk between EGF and TRPM6 and Novel Implications for Cetuximab Therapy

Hypomagnesemia is very commonly observed in cancer patients, most frequently in association with therapy with cetuximab (CTX), a monoclonal antibody targeting the epithelial growth factor receptor (EGFR). CTX-induced hypomagnesemia has been ascribed to renal magnesium (Mg) wasting. Here, we sought to clarify whether CTX may also influence intestinal Mg absorption and if Mg supplementation may interfere with CTX activity. We used human colon carcinoma CaCo-2 cells as an in vitro model to study the mechanisms underlying Mg transport and CTX activity. Our findings demonstrate that TRPM6 is the key channel that mediates Mg influx in intestinal cells and that EGF stimulates such influx; consequently, CTX downregulates TRPM6-mediated Mg influx by interfering with EGF signaling. Moreover, we show that Mg supplementation does not modify either the CTX IC50 or CTX-dependent inhibition of ERK1/2 phosphorylation. Our results suggest that reduced Mg absorption in the intestine may contribute to the severe hypomagnesemia that occurs in CTX-treated patients, and Mg supplementation may represent a safe and effective nutritional intervention to restore Mg status without impairing the CTX efficacy.

Tumor calcification as a prognostic factor in cetuximab plus chemotherapy-treated patients with metastatic colorectal cancer

Supplemental Digital Content is available in the text.

This study aimed to explore the correlation between survival and tumor calcification in patients with metastatic colorectal cancer who received cetuximab combined with chemotherapy. The study was a single-center retrospective analysis that enrolled 111 patients who had received therapy between April 2011 and October 2016. Tumor calcification and treatment efficacy were evaluated independently by radiologists on the basis of computed tomography scans. Clinical characteristics and follow-up data were collected from electronic medical records. Correlations between tumor calcification and clinical characteristics, tumor response rate, and patient survival were analyzed. Among the 111 enrolled patients, 27 had tumor calcification [27/111 (24.3%)]. The median progression-free survival was significantly longer for patients with tumor calcification than for those without calcification (9.3 vs. 6.2 months, P=0.022). Patients with tumor calcification also had a higher objective response rate (55.6 vs. 31%, P=0.021) and better overall survival (21.9 vs. 16.5 months, P=0.084). The correlation between calcification features and prognosis showed that patients with an increasing number of calcifications after treatment had a significantly longer median overall survival (22.9 vs. 9.1 months, P=0.033). Simultaneously, new liver metastases and multiple calcifications also showed a trend toward better overall survival. There were also no significant correlations between clinical characteristics (sex, age, gene mutation, primary tumor location, pathological type, blood test result) and survival (Supplementary Table 1, Supplemental digital content 1, http://links.lww.com/ACD/A280). Tumor calcification is associated with a better treatment outcome and is a potential prognostic marker.

Identifying optimal magnesium replenishment points based on risk of severe hypomagnesemia in colorectal cancer patients treated with cetuximab or panitumumab

PURPOSE

Cetuximab and panitumumab are monoclonal antibodies that target the epidermal growth factor receptor (EGFR). Treatment with cetuximab and panitumumab commonly causes hypomagnesemia, and optimal management of this adverse effect remains unclear. Here, we evaluated the optimal magnesium replacement points based on the risk of severe hypomagnesemia in colorectal cancer patients who received cetuximab or panitumumab.

METHODS

We retrospectively evaluated 184 patients who received cetuximab or panitumumab for colorectal cancer at Ogaki Municipal Hospital (Ogaki, Japan) between January 2010 and December 2019. Univariate analyses were conducted to evaluate the relationship between patient baseline characteristics and development of hypomagnesemia following cetuximab or panitumumab treatment. Variables that were significantly associated with hypomagnesemia in the univariate analyses as well as previously reported risk factors were entered into a multivariate logistic regression model.

RESULTS

The incidence of hypomagnesemia was associated with panitumumab treatment, pre-replenishment serum magnesium concentration, treatment duration, and treatment line. Severe hypomagnesemia post-cetuximab or panitumumab treatment was significantly associated with low baseline magnesium concentrations (< 1.8 mg/dL; odds ratio 18.100, 95% confidence interval 1.570-210.000; p = 0.020) and low serum magnesium concentrations during treatment (< 1.1 mg/dL; odds ratio 93.800, 95% confidence interval 3.510-2510.000; p = 0.007).

CONCLUSION

To minimize the risk of severe hypomagnesemia during anti-EGFR treatment, magnesium replenishment should be initiated in patients with pre-replenishment concentrations of < 1.8 mg/dL, preferably before reaching intra-treatment concentrations of < 1.1 mg/dL.

[Renal toxicities of targeted therapies in oncology]

The advent of new molecules oncology including targeted therapies, has resulted in improved patient survival over standard chemotherapy. The renal toxicities of these anticancer agents are more and more recognized and vary according to the targeted therapeutic target. This article reviews the renal toxicity associated with targeted anticancer therapies directed against Epidermal growth factor receptor, Human epidermal growth factor-2, B-rapidly accelerated fibrosarcoma, Mitogen-activated protein kinase, Anaplastic lymphoma kinase, Programmed cell death-1/programmed cell death ligand-1, Cytotoxic T lymphocyte antigen-4 and Vascular endothelial growth factor/receptor. The early diagnosis and management of these renal adverse events is essential for the clinician who cares for such patients.

Temporary loss of consciousness during cetuximab treatment of a patient with metastatic colon cancer: a case report

BACKGROUND

Anti-epidermal growth factor receptor (EGFR) antibody is widely used for the treatment of patients with metastatic colorectal cancer. Hypomagnesemia is a comparatively frequent adverse event of this drug, which is likely overlooked because it occurs later in treatment without symptoms. Furthermore, hypomagnesemia and hypomagnesemia-induced corrected QT (QTc) prolongation may lead to loss of consciousness (LOC), the onset of which is not generally considered associated with the treatment of anti-EGFR antibody because of its rare occurrence. Here, we present a colorectal cancer patient treated with anti-EGFR antibody, who suffered LOC during treatment while severe hypomagnesemia or QTc prolongation was not observed.

CASE PRESENTATION

A 69-year-old man with metastatic colon cancer was treated with cetuximab (anti-EGFR antibody) plus irinotecan as third-line chemotherapy. His serum magnesium level gradually decreased, and grade 2 hypomagnesemia (a serum magnesium level of 0.9 mg/dL) was observed at the 12th administration of cetuximab. In light of this development, intravenous supplementation of 20 mEq magnesium sulfate began with careful blood monitoring despite the lack of clinical symptoms. Electrocardiogram (ECG) showed prolonged QT or corrected QT (QTc) intervals (grade 1). His serum magnesium level remained at 0.9 mg/dL, and no hypomagnesemia symptoms were observed by the 17th administration of cetuximab. After the treatment, however, he suddenly lost consciousness without symptoms related to infusion or allergic reactions. Circulatory collapse following dermatological reactions and respiratory events were not evident. Intravenous supplementation of magnesium sulfate was administered again. He awakened 2 min after the onset of temporary LOC without any other symptoms related to hypomagnesemia, such as lethargy, tremor, tetany, and seizures. No other etiology outside of the low level of serum magnesium was confirmed in further examinations. Cetuximab was discontinued, and his serum magnesium level returned to a level within the normal range after 6 weeks. Because of tumor progression, regorafenib and TAS-102 (trifluridine tipiracil hydrochloride) were introduced sequentially for 6 months. Five months after the final treatment of TAS-102, he died of his primary disease, which reflected a survival period of 4 years and 6 months since the beginning of treatment.

CONCLUSIONS

This case report reminds clinicians that LOC can be induced without severe hypomagnesemia or QTc prolongation, during anti-EGFR antibody treatment for metastatic colorectal cancer even while under carefully monitored magnesium supplementation.

Hypomagnesemia and Survival in Patients with Ovarian Cancer Who Received Chemotherapy with Carboplatin

BACKGROUND

Hypomagnesemia is a known side effect of several antineoplastic agents, but its impact on outcomes of patients with cancer is not well understood. We examined whether magnesium abnormalities affect survival in patients with ovarian cancer who receive chemotherapy containing carboplatin.

MATERIALS AND METHODS

We included patients with advanced ovarian cancer who had undergone surgery and chemotherapy between January 1, 2004, and December 31, 2014, at our institution. Inclusion criteria were age 18 years or older, pathology of high-grade serous carcinoma, first treatment (surgery or chemotherapy) within 60 days of diagnosis, and chemotherapy containing carboplatin. The final cohort consisted of 229 patients. Vital signs and laboratory tests were recorded at baseline and during the treatment course. The associations between magnesium abnormalities (and other clinical characteristics) and survival were analyzed.

RESULTS

The median patient age was 64 years. Higher baseline heart rate (beats per minute; hazard ratio [HR] = 1.02, p = .002) and greater frequency of hypomagnesemia during the treatment course (HR = 1.05, p = .002) were significantly associated with shorter survival independent of completeness of tumor reduction (HR = 1.60, p = .02), and International Federation of Gynecology and Obstetrics stage (HR = 1.63, p = .01).

CONCLUSION

Baseline heart rate and the frequency of hypomagnesemia episodes during treatment are prognostic of survival for patients with advanced ovarian cancer receiving carboplatin-containing chemotherapy and tumor reductive surgery. Future research is needed for strategies to detect and prevent hypomagnesemia in this patient population.

IMPLICATIONS FOR PRACTICE

Despite standard laboratory tests and intravenous magnesium replacement prior to each cycle of chemotherapy, hypomagnesemia remains a common side effect of platinum-based chemotherapy. This study revealed that frequent occurrence of hypomagnesemia during the course of treatment including carboplatin-containing chemotherapy and tumor reductive surgery was strongly predictive of shorter survival in patients with advanced ovarian cancer. Strategies to effectively mitigate hypomagnesemia, such as more frequent detection, dietary recommendations, and timely replacement, should be considered in the overall cancer treatment plan for these patients.

Adverse kidney effects of epidermal growth factor receptor inhibitors

The epidermal growth factor receptor (EGFR) is implicated in various malignancies. The past decade has seen the development and widespread use of EGFR inhibitors for the successful treatment of such cancers. Available EGFR inhibitors include small molecule tyrosine-kinase inhibitors and monoclonal antibodies. Class-related renal adverse events result in dual toxicity including tubular/electrolyte disorders and glomerulopathies. Tubular injury is common and mainly due to monoclonal antibodies while glomerulopathy is rare and related to various anti-EGFR agents. The exact pathogenesis of anti-EGFR agents associated with kidney disorders remains to be elucidated.

Chemotherapy in patient with colon cancer after renal transplantation: A case report with literature review

RATIONALE

Experience of pharmacotherapy in posttransplantation colorectal cancer (CRC) patients is inadequate.

PATIENT CONCERNS

A Chinese man had right renal transplantation and began immunosuppressive treatment at the age of 31 in 2009. He was diagnosed with colon cancer and underwent anterior resection in 2014. He was diagnosed with metastatic colon carcinoma by abdomen computed tomography (CT) and positron emission tomography-computed tomography in April 2017.

DIAGNOSIS

Metastatic colon carcinoma in posttransplantation patient.

INTERVENTIONS

Three cycles of FLOFOX (5-fluorouracil and leucovorin and oxaliplatin) chemotherapy were given since April 2017.

OUTCOMES

Plasma concentrations of immunosuppressant and kidney function were within normal during the chemotherapy. Abdomen CT revealed the progress of colon cancer at the end of the third course of chemotherapy.

LESSONS

A few cases about monochemotherapy of posttransplantation CRC have been reported, whereas experience of doublet chemotherapy was currently unavailable. We shared the experience of FOLFOX in a patient with posttransplantation colon cancer. Neither of incompatibility with immunosuppressant nor serious adverse drug reaction was observed. It provides evidence for the pharmacotherapy of posttransplantation CRC.

Hypomagnesemia and clinical benefits of anti-EGFR monoclonal antibodies in wild-type KRAS metastatic colorectal cancer: a systematic review and meta-analysis

Hypomagnesemia is a recognized side-effect of cetuximab- or panitumumab-based chemotherapy for metastatic colorectal cancer (mCRC). The clinical relevance of hypomagnesemia is under debate. Thus, a systematic review and meta-analysis of retrospective studies and randomized clinical trials (RCTs) comparing hypomagnesemia with normal magnesium levels in wild-type KRAS mCRC was performed. One RCT, two retrospective studies, and two American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO) conference presentations from phase III RCTs involving 1723 patients were included in this study. Patients with hypomagnesemia demonstrated better progression-free survival (PFS) (Hazard ratio [HR]: 0.64; 95% confidence interval [CI]: 0.47–0.88), overall survival (OS) (HR: 0.72; 95% CI: 0.53–0.92), and objective response rate (ORR) (Risk ratio [RR]: 1.81; 95% confidence interval [CI]: 1.30–2.52). By subgroup analysis, frontline, later lines or combination therapy with hypomagnesemia were associated with PFS benefits (HR: 0.78; 95% CI: 0.62–0.98; HR: 0.60; 95% CI: 0.40–0.90; HR: 0.62; 95% CI: 0.41–0.94, respectively). In patients with wild-type KRAS mCRC, hypomagnesemia is associated with better clinical benefits of PFS, OS and ORR when treated with cetuximab- or panitumumab-based chemotherapy. Future clinical trials should corroborate its predictive role.

Durable complete remission following anti-EGFR antibodies in recurrent metastatic colorectal cancer

In this case report, we describe a patient who remains in complete remission two years after the discontinuation of anti-EGFR monotherapy as a third-line treatment, accompanied by persistent severe hypomagnesemia. A 45-year-old Caucasian woman with mCRC started chemotherapy with weekly cetuximab. After ten months of treatment, the therapy was stopped because the patient had persistent grade III hypomagnesemia despite amiloride, oral, and intravenous magnesium. A month later, the patient was switched to panitumumab 6 mg/kg every two weeks for four additional months to avoid weekly visits to the clinic. Following discontinuation of panitumumab, PET scans remain negative to this day, two years after anti-EGFR therapy discontinuation. No factor has been identified to explain the complete and sustained response experienced by this patient. Hypomagnesemia is a common adverse effect of anti-EGFR therapy that can lead to treatment interruption and discontinuation if severe. This case highlights the importance of pursuing anti-EGFR therapy when a response is observed in spite of severe hypomagnesemia. It also provides preliminary information that anti-EGFR therapy could be stopped after a complete response is obtained.

Activity of weekly paclitaxel-cetuximab chemotherapy in unselected patients with recurrent/metastatic head and neck squamous cell carcinoma: prognostic factors

BACKGROUND

Standard treatment for recurrent/metastatic head and neck squamous cell carcinoma (RM-SCCHN) is based in on platinum and cetuximab combination therapy. Unfortunately, not all patients are candidates to receive platinum-based treatment, because of different conditions as comorbidity and poor performance status. Weekly paclitaxel and cetuximab (WPC) is an active therapeutic alternative, based on a phase II study, with less toxicity. Our main objective is to confirm its activity in unselected patients, mostly unfit for aggressive therapies, analysing also some clinically relevant prognostic factors (PFs).

METHODS

Retrospective data was collected for RM-SCCHN patients, treated at our institution between January 2008 and July 2014 with weekly paclitaxel (80 mg/m²) and cetuximab (400/250 mg/m²).

RESULTS

148 patients were treated. The objective response rate (OR) was as follows: 13 patients (8.78%) complete response (CR); 57 patients (38.51%) partial response (PR) and 30 patients (20.3%) stable disease (SD). Median overall survival (OS) was 10 months (95% CI 8.31-11.69) and median progression free survival (PFS) was 7 months (95% CI 5.88-8.12). Response to treatment showed independent prognosis relevance as PF in multivariate analysis for PFS and OS. Furthermore, decline in serum magnesium during the treatment was also an independent PF for OS.

CONCLUSIONS

WPC activity was confirmed as a useful therapy on real-life unselected RM-SCCHN patients, with similar benefit to that obtained in the phase II study, and comparable to platinum and cetuximab based treatment, confirming its value in unfit patients. In addition to treatment response, a change in serum magnesium values during treatment was proved as independent PF on OS.

Final results and outcomes by prior bevacizumab exposure, skin toxicity, and hypomagnesaemia from ASPECCT: randomized phase 3 non-inferiority study of panitumumab versus cetuximab in chemorefractory wild-type KRAS exon 2 metastatic colorectal cancer

PURPOSE

The primary analysis of the ASPECCT study demonstrated that panitumumab was non-inferior to cetuximab for overall survival (OS) in patients with chemotherapy-refractory wild-type KRAS exon 2 metastatic colorectal cancer (mCRC). Here, we report the final analysis results of ASPECCT.

PATIENTS AND METHODS

Patients with wild-type KRAS exon 2 mCRC who progressed on or were intolerant to irinotecan- or oxaliplatin-based chemotherapy were randomised to receive panitumumab 6 mg/kg once every 2 weeks or cetuximab (400 mg/m²) followed by 250 mg/m² weekly. The primary end-point was OS assessed for non-inferiority. Patients were followed for survival for 24 months after the last patient was randomised and a final analysis was conducted. No formal hypothesis testing was done. Post hoc analyses of outcomes by prior bevacizumab exposure, worst-grade skin toxicity (0-1 versus 2-4) and worst-grade hypomagnesaemia (0 versus 1-4) were conducted.

RESULTS

Nine hundred ninety-nine patients were randomised and received ≥1 treatment dose (panitumumab, n = 499; cetuximab, n = 500). Median OS was 10.2 months with panitumumab versus 9.9 months with cetuximab (hazard ratio = 0.94; 95% confidence interval = 0.82-1.07). Median progression-free survival was 4.2 months with panitumumab and 4.4 months with cetuximab (hazard ratio = 0.98; 95% confidence interval = 0.87-1.12). Longer OS was observed for patients with increased skin toxicity and with hypomagnesaemia in both arms. Furthermore, OS was longer for patients with prior bevacizumab exposure treated with panitumumab than with cetuximab. The observed safety profiles were consistent with previous studies.

CONCLUSION

Consistent with the primary analysis, the final analysis of ASPECCT showed panitumumab was non-inferior to cetuximab for OS for patients with chemotherapy-refractory, wild-type KRAS exon 2 mCRC.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01001377.

Hypomagnesemia is a reliable predictor for efficacy of anti-EGFR monoclonal antibody used in combination with first-line chemotherapy for metastatic colorectal cancer

PURPOSE

Anti-EGFR monoclonal antibody is effective for KRAS wild-type metastatic colorectal cancer (mCRC), but frequently causes several adverse reactions, including hypomagnesemia and skin disorders. The present study was designed to investigate the relationship between the incidence of adverse reactions and therapeutic effects in mCRC patients receiving anti-EGFR monoclonal antibody in combination with first-line chemotherapy.

METHODS

Forty-three mCRC patients who received cetuximab or panitumumab between April 2012 and December 2015 were the subjects of the present study. All patients were pretreated with oral minocycline in combination with skin treatment using moisturizer for prevention of skin rash. Hypomagnesemia and acneiform rash were graded according to the Common Terminology Criteria for Adverse Events, version 3.0. Overall response rate (ORR) and time to treatment failure (TTF) were compared between patients with and without these adverse events.

RESULTS

The incidence rates of hypomagnesemia and acneiform rash were 32.6 % (grade 1: 20.9 %, grade 2: 11.6 %) and 93.0 % (grade 1: 41.9 %, grade 2: 41.9 %, grade 3: 9.3 %), respectively. ORR was significantly higher in patients with hypomagnesemia than in those without it (71.4 vs 34.5 %, P = 0.048). Median TTF tended to be longer, though not significantly, in patients with hypomagnesemia than in those without it. However, no significant difference in both ORR and median TTF was observed between patients with and without acneiform rash.

CONCLUSION

Hypomagnesemia may become a predicting factor for therapeutic effects of anti-EGFR monoclonal antibody in mCRC patients.

Electrolyte disorders associated with the use of anticancer drugs

The use of anticancer drugs is beneficial for patients with malignancies but is frequently associated with the occurrence of electrolyte disorders, which can be hazardous and in many cases fatal. The review presents the electrolyte abnormalities that can occur with the use of anticancer drugs and provides the related mechanisms. Platinum-containing anticancer drugs induce hypomagnesemia, hypokalemia and hypocalcemia. Moreover, platinum-containing drugs are associated with hyponatremia, especially when combined with large volumes of hypotonic fluids aiming to prevent nephrotoxicity. Alkylating agents have been linked with the occurrence of hyponatremia [due to syndrome of inappropriate antidiuretic hormone secretion (SIADH)] and Fanconi's syndrome (hypophosphatemia, aminoaciduria, hypouricemia and/or glucosuria). Vinca alkaloids are associated with hyponatremia due to SIADH. Epidermal growth factor receptor monoclonal antibody inhibitors induce hypomagnesemia, hypokalemia and hypocalcemia. Other, monoclonal antibodies, such as cixutumumab, cause hyponatremia due to SIADH. Tyrosine kinase inhibitors are linked to hyponatremia and hypophosphatemia. Mammalian target of rapamycin inhibitors induce hyponatremia (due to aldosterone resistance), hypokalemia and hypophosphatemia. Other drugs such as immunomodulators or methotrexate have been also associated with hyponatremia. The administration of estrogens at high doses, streptozocin, azacitidine and suramin may induce hypophosphatemia. Finally, the drug-related tumor lysis syndrome is associated with hyperphosphatemia, hyperkalemia and hypocalcemia. The prevention of electrolyte derangements may lead to reduction of adverse events during the administration of anticancer drugs.

Management of Epidermal Growth Factor Receptor Inhibitor-Induced Hypomagnesemia: A Systematic Review

BACKGROUND

Despite occurring in 30% of patients, there are no evidence-based guidelines on the management of epidermal growth factor receptor inhibitor (EGFRI)-induced hypomagnesemia. Based on expert opinion, severe hypomagnesemia should be treated by intravenous magnesium replacement. A systematic review of published data of intervention on EGFRI-induced hypomagnesemia was performed.

METHODS

Articles from 1960 to March 2015 were identified from Medline, Embase, Cochrane Central Register of Controlled Trials, and PubMed using a peer-reviewed systematic search strategy. Eligible studies included randomized controlled trials or observational studies that evaluated management of hypomagnesemia in adult patients treated with EGFRIs. Risk factors for severe hypomagnesemia were also assessed. The quality of included studies was rated using Jadad scores.

RESULTS

A total of 1327 references were identified, and 6 studies, involving 486 patients, met inclusion criteria for analysis. There were no randomized controlled trials, and all included studies were of poor quality. From the studies included in this review, severity of EGFRI-induced hypomagnesemia was associated with length of EGFRI treatment, concomitant platinum chemotherapy, increasing age, and baseline magnesium concentration. In most patients with grade 3 or 4 hypomagnesemia, high-dose intravenous magnesium replacement did not achieve sustainable magnesium repletion beyond 72 hours. Oral magnesium supplementation was not effective or tolerable. Severe hypomagnesemia has been associated with tachycardia and mental alteration. After discontinuation of EGFRI therapy, hypomagnesemia generally resolves within weeks to months.

CONCLUSIONS

There is an absence of high-quality evidence for the management of EGFRI-induced hypomagnesemia. As hypomagnesemia is often refractory to frequent intravenous or oral replacement, there is a need for prospective trials of new interventions for this common toxicity.

Pharmacokinetic and pharmacodynamic evaluation of panitumumab in the treatment of colorectal cancer

INTRODUCTION

Integration of targeted therapy and additional chemotherapy options has improved median overall survival (OS) in patients with unresectable metastatic colorectal cancer (mCRC). Cetuximab and panitumumab are examples of targeted therapies, specifically against the epidermal growth factor receptor (EGFR). This review focuses on Panitumumab, a fully human IgG2 monoclonal antibody, which inhibits key oncogenic downstream cell signalling pathways. Panitumumab and cetuximab have improved tumour response rate, progression-free survival, and OS in mCRC patients in whom the RAS (Rat Sarcoma) gene is of Wild Type (WT) status.

AREAS COVERED

The EGFR signalling pathway and preclinical, Phase I and Phase II clinical studies on the pharmacokinetic, pharmacodynamic and safety evaluation of panitumumab are presented. Phase III studies utilising panitumumab in the first, second and third line setting in mCRC are also described.

EXPERT OPINION

Panitumumab exhibits excellent pharmacokinetics and pharmacodynamics by way of uncomplicated dosing, non-existent drug interactions, minimal infusion reactions and manageable side effects, making it a suitable target for combination treatments. However, innate and acquired resistances are still obstacles. To overcome this, experimented strategies are ongoing, particularly in patients with Her-2 and BRAF gene alterations. Novel biomarkers to improve patient selection and second-generation targeted antibodies are in development.

Assessment of frequency and severity of hypomagnesemia in patients with metastatic colorectal cancer treated with cetuximab, with a review of the literature

Currently, there are a few systemic treatment options for patients with metastatic colorectal cancer (mCRC). Targeted therapy used in this setting includes the use of monoclonal antibodies, such as cetuximab or panitumumab, directed against epidermal growth factor receptor. The aim of the present study was to estimate the frequency and severity of hypomagnesemia among patients with mCRC treated with cetuximab. The data from the Department of Clinical Oncology, University Hospital of Krakow (Krakow, Poland), concerning 52 patients treated between 2009 and 2013 were collected. Of these, 27 patients fulfilled the inclusion criteria to enter this retrospective study. The National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 were used to grade the level of hypomagnesemia. In total, 29.6% of all patients experienced hypomagnesemia during treatment, and the majority of cases were grade 1 (22.2%). There was no statistically significant correlation between magnesium (Mg) level and patient age, duration of treatment, localization of primary tumor or metastases, and the number of metastases. However, there was an upward trend in a logistic regression model showing that the risk of developing hypomagnesemia increases with age. Hypomagnesemia is a frequent problem among mCRC patients receiving cetuximab. It is essential to introduce guidelines regarding the monitoring of the Mg level and its supplementation in this group of patients.

Prognostic and predictive response factors in colorectal cancer patients: Between hope and reality

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e., bevacizumab, cetuximab and panitumab), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Many questions needing of right collocations and more clearness still exist regarding the prognostic factors and the predictive factors of response to therapy. Despite advances in dosing and scheduling of chemotherapy in both adjuvant and advanced settings, and a greater emphasis on early detection, the outlook still remains poor for most patients. Molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumours may have different long term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of prognostic factors and predictive factors according to the recently published English literature.

Panitumumab safety for treating colorectal cancer

INTRODUCTION

Panitumumab is a human IgG2 mAb against the EGFR, inhibiting tumor cell proliferation, survival and angiogenesis. It has demonstrated clinical efficacy in metastatic colorectal cancer (CRC) in combination with chemotherapy in first- and second-line settings and as monotherapy in third-line setting. Recently, mutations in the RAS genes have been shown to be predictive of lack of efficacy, panitumumab should be restricted to patients with RAS wild-type (wt) tumors.

AREAS COVERED

This review focuses on main efficacy results of panitumumab in metastatic CRC in first-, second- and third-line settings in combination with chemotherapy or as monotherapy. Additionally, we have covered safety aspects of this agent in these indications, especially in K-RAS and all RAS wt patients. These safety aspects refer to the most common toxicities (i.e., acne-like skin rash, diarrhea and hypomagnesaemia).

EXPERT OPINION

Panitumumab adds to the armamentarium of effective agents in the treatment of metastatic CRC. Due to its human origin, panitumumab is a well-tolerated agent with low rates of infusional reactions. Skin toxicity is frequent and should be pre-emptively treated. Other common toxicities related to panitumumab treatment, such as diarrhea and hypomagnesaemia, should be closely monitored to ensure early treatment or substitution.

Epidermal growth factor receptor: pathway, therapies, and pipeline

BACKGROUND

The epidermal growth factor receptor (EGFR) pathway is important in tumor growth, survival, and metastasis and is now the target of several therapeutic agents.

OBJECTIVES

This paper seeks to review the EGFR pathway, the study and use of EGFR-directed agents in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC), and related new drug development.

METHODS

PubMed was searched for English-language articles by MeSH and title terms of EGFR published from 2006 to 2013, using the limits of clinical trials as well as reviews. Reference lists were assessed for relevant articles, and guidelines were searched. Clinicaltrials.gov and meeting abstracts were queried for investigational agents. Eligible papers included those concerning EGFR biology, NSCLC or CRC studies involving EGFR-directed agents, and/or investigational drugs targeting EGFR and/or associated pathways.

RESULTS

The activity of oral tyrosine kinase inhibitors (TKIs) against EGFR has improved survival in NSCLC, and these agents particularly effective in cancers with an EGFR mutation. Resistance to TKIs is most commonly related to a second, T790M, mutation, or to MET amplification, with newer agents directed against these mechanisms. Conversely, in CRC, TKIs have been ineffective, whereas monoclonal antibodies have improved survival. Both primary and secondary KRAS mutations in CRC abrogate mAb effectiveness. Several targets, including MET, BRAF, and PI3K, may serve useful in combination with anti-EGFR drugs.

CONCLUSIONS

Exploitation of EGFR-directed therapies has offered improvement in survival and quality of life in NSCLC and CRC. New therapies directed at EGFR may offer further improvements. However, resistance mechanisms suggest that combination therapies or multitargeted agents will be crucial in making significant future advances.

Biweekly cetuximab plus FOLFIRI/irinotecan as first/second-line chemotherapy for patients with KRAS wild-type metastatic colorectal cancer: a retrospective analysis in Southwest Chinese population

Weekly cetuximab plus irinotecan-based regiments are standard first- and second-line chemotherapy for patients with KRAS wild-type metastatic colorectal cancer (mCRC). However, the chemotherapy regimens are given every 2 weeks, which is asynchronous with cetuximab weekly administration. This study investigated the efficacy and safety of biweekly cetuximab administration in patients with mCRC. Twenty-six patients with KRAS wild-type mCRC, who received biweekly cetuximab plus FOLFIRI/irinotecan as first/second-line chemotherapy, at least three cycles of cetuximab and once CT evaluation in West China Hospital from May 2010 to February 2013, were retrospectively analyzed. The median number of cetuximab administrations was 8.3 (range 3-20). Fourteen patients received FOLFIRI as first-line therapy; response rate was 50.0%; median PFS was 8.8 months (95% CI 4.9-12.7). Ten patients received FOLFIRI and two patients received irinotecan as second-line therapy; response rate was 33.3%; median PFS was 4.6 months (95% CI 0.9-8.3). The toxicity was similar to weekly cetuximab combination schedules. Rash was observed in 69.2% of evaluable patients (grade 3 in 7.7%). Overall, our results show that biweekly cetuximab plus FOLFIRI/irinotecan may be as effective and safe as the standard weekly schedule.