Evolving insights into the mechanisms of toxicity associated with immune checkpoint inhibitor therapy.

Immune checkpoint inhibitors have emerged as a revolutionary treatment option for patients with various types of malignancy. Although these agents afford a significant improvement in outcomes for melanoma and other previously untreatable malignancies, their novel mechanism of action may predispose patients to immune-related adverse effects (irAEs). In the tumour neoantigen environment, these irAEs are due to the activation of the immune system by the blockade of suppressive checkpoints, leading to increases in T-cell activation and proliferation. IrAEs have been reported in almost any organ and at any point in time, even months to years after discontinuation of therapy. Certain populations with distinct physiological changes, genetic risk factors, and specific antigen exposures may be more highly predisposed to develop irAEs. This review discusses the incidence and mechanisms of irAEs and the relationship between host factors and irAE occurrence.

Durable responses in refractory autoimmune hemolytic anemia with alemtuzumab.

Autoimmune hemolytic anemia occurs due to an interaction of IgG antibodies with protein antigens expressed on red blood corpuscles. Glucocorticoids are the mainstay of treatment for autoimmune hemolytic anemia. For patients not responding to initial therapy, other agents such as rituximab, immunosuppressive therapy, or splenectomy are considered. When refractory to these treatment options, alemtuzumab is an alternative agent. However, long-term outcomes of patients supporting its use are lacking. We present three patients with refractory autoimmune hemolytic anemia treated with alemtuzumab.

Effect of Concomitant pH-Elevating Medications with Pazopanib on Progression-Free Survival and Overall Survival in Patients with Metastatic Renal Cell Carcinoma.

BACKGROUND: Pazopanib is an oral tyrosine-kinase inhibitor that is approved by the U.S. Food and Drug Administration for treatment of metastatic renal cell carcinoma (mRCC). Pharmacokinetic data have shown that concomitant administration of pazopanib and esomeprazole, a proton pump inhibitor (PPI), leads to decreased area under the curve and thus decreased exposure of pazopanib by 40%. Despite the pharmacokinetic data published to date, the clinical significance and impact on patient outcomes resulting from decreased pazopanib exposure remains unknown. MATERIALS AND METHODS: In this retrospective, observational, cohort study, 90 patients with mRCC who either received pazopanib in combination with a PPI or histamine 2 receptor antagonist (H2RA; concurrent PPI/H2RA group) or who did not take concurrent pH-elevating medications (no PPI/H2RA group) were compared to determine if there was an impact on progression-free survival (PFS), the primary endpoint, and secondary endpoints, overall survival (OS) and safety. RESULTS: The differences between the PFS of 9.0 months and OS of 28.0 months for the concomitant PPI/H2RA group versus 11.0 months and 30.1 months, respectively, for the no PPI/H2RA group were not statistically significant. Rates of adverse events were similar between the concomitant PPI/H2RA and no PPI/H2RA groups. CONCLUSION: Concomitant PPI or H2RA usage was not shown to be associated with a reduction in PFS or OS for patients receiving pazopanib for mRCC, with a similar toxicity profile in each group. Based on the results of this retrospective cohort study and the palliative nature of the treatment of patients with mRCC, clinicians should consider allowing patients to remain on concomitant pazopanib and acid-reducing therapy. IMPLICATIONS FOR PRACTICE: Pazopanib is a preferred category-one first-line treatment for predominant clear cell metastatic renal cell carcinoma (mRCC). However, because of an aging demographic, coupled with patients with mRCC presenting with multiple comorbidities, including symptomatic dyspepsia or gastroesophageal reflux disease, patients are commonly required to take pazopanib concomitantly with a proton pump inhibitor (PPI) or a histamine 2 receptor antagonist (H2RA). Despite earlier pharmacokinetic reports suggesting that an alkaline pH may result in poorer absorption, this institutional retrospective study found no effect on clinical outcomes. These data suggest that concurrent treatment of mRCC with pazopanib and a PPI or H2RA may be safe in everyday practice.

The Association between a Decrease in On-Treatment Neutrophil-to-Eosinophil Ratio (NER) at Week 6 after Ipilimumab Plus Nivolumab Initiation and Improved Clinical Outcomes in Metastatic Renal Cell Carcinoma.

A lower baseline neutrophil-to-eosinophil ratio (NER) has been associated with improved responses to immune checkpoint inhibitors (ICI)-treated metastatic renal cell carcinoma (mRCC). This study investigated the decrease in NER at week 6 after ipilimumab/nivolumab (ipi/nivo) initiation and treatment responses in mRCC. A retrospective study of ipi/nivo-treated mRCC at two US academic cancer centers was conducted. A landmark analysis at week 6 was performed to assess the association between the change in NER and clinical responses (progression-free survival (PFS)/overall survival (OS)). Week 6 NER was modeled as a continuous variable, after log transformation (Ln NER), and a categorical variable by percent change. There were 150 mRCC patients included: 78% had clear cell histology, and 78% were IMDC intermediate/poor risk. In multivariable regression analysis, every decrease of 1 unit of Ln NER at week 6 was associated with improved PFS (adjusted hazard ratio (AHR): 0.78, p-value:0.005) and OS (AHR: 0.67, p-value: 0.002). When NER was modeled by percent change, decreased NER > 50% was associated with improved PFS (AHR: 0.55, p-value: 0.03) and OS (AHR: 0.37, p-value: 0.02). The decrease in week 6 NER was associated with improved PFS/OS in ipi/nivo-treated mRCC. Prospective studies are warranted to validate NER change as a biomarker to predict ICI responses.

Minimal Prolongation of Prothrombin Time with Extended Exposure to Argatroban.

In the setting of acute heparin-induced thrombocytopenia (HIT), argatroban is one of the initial anticoagulants of choice, which is eventually bridged to warfarin over a period of 5 or more days. Argatroban prolongs prothrombin time (PT) and increases international normalized ratio (INR). However, the effects of prolonged argatroban exposure on the PT and INR are not known. We describe an unusual case of prolonged argatroban treatment in a patient with heparin-induced thrombocytopenia with thrombosis syndrome (HITTS) resulting in a minimal elevation of the INR. The patient received a total of 58 days of argatroban and was resistant to warfarin therapy, requiring a 13-day bridge to achieve a therapeutic INR of 2.0 to 3.0. Ultimately, argatroban was successfully transitioned to warfarin therapy when the INR was 2.7 on both agents, producing the confirmatory true INR of 2.4. Argatroban and warfarin cotherapy did not increase the INR beyond 4.0 after prolonged argatroban exposure. Clinicians should consider this unusual response in other cases of prolonged argatroban use, and monitor INR carefully during warfarin and argatroban cotherapy. The use of other methods to monitor anticoagulant therapy, such as chromogenic factor X assay (CFX), may be helpful in this setting.