Immune and autoimmune-related adverse events associated with immune checkpoint inhibitors in cancer therapy

The recent development of monoclonal antibodies that disinhibit the immune system from recognizing and attacking tumor cells has revolutionized the treatment of cancer. Among these agents are drugs that specifically block cytotoxic T-lymphocyte protein 4 (CTLA-4), programmed cell death protein 1 (PD-1) and programmed cell death 1 ligand 1 (PD-L1) signaling, called immune checkpoint inhibitors (ICIs). While these agents are generally well tolerated, ICI therapy can lead to loss of self-tolerance and the development of autoimmunity, manifesting as immune-related adverse events (IRAEs). Although potentially linked to increased antitumor responses, the morbidity associated with IRAEs can be significant and in rare circumstances, fatal. Virtually any organ can be affected and the patients present with a broad range of signs and symptoms. Moreover, ICIs have varying IRAEs and have distinct toxicity profiles based on their mechanism of action. Fortunately, most of the IRAEs can be managed with immunosuppression and supportive care, but contingent on early recognition and prompt treatment. With increasing advances in drug development, including combination ICI therapy, these agents are becoming one of the most prescribed oncology drugs and clinicians should be knowledgeable about the recognition and management of IRAEs.

A phase 1, dose-escalation study of PF-06664178, an anti-Trop-2/Aur0101 antibody-drug conjugate in patients with advanced or metastatic solid tumors

Purpose and Methods Trop-2 is a glycoprotein over-expressed in many solid tumors but at low levels in normal human tissue, providing a potential therapeutic target. We conducted a phase 1 dose-finding study of PF-06664178, an antibody-drug conjugate that targets Trop-2 for the selective delivery of the cytotoxic payload Aur0101. The primary objective was to determine the maximum tolerated dose and recommended phase 2 dose. Secondary objectives included further characterization of the safety profile, pharmacokinetics and antitumor activity. Eligible patients were enrolled and received multiple escalating doses of PF-06664178 in an open-label and unblinded manner based on a modified continual reassessment method. Results Thirty-one patients with advanced or metastatic solid tumors were treated with escalating doses of PF-06664178 given intravenously every 21 days. Doses explored ranged from 0.15 mg/kg to 4.8 mg/kg. Seven patients experienced at least one dose limiting toxicity (DLT), either neutropenia or rash. Doses of 3.60 mg/kg, 4.2 mg/kg and 4.8 mg/kg were considered intolerable due to DLTs in skin rash, mucosa and neutropenia. Best overall response was stable disease in 11 patients (37.9%). None of the patients had a partial or complete response. Systemic exposure of PF-06664178 increased in a dose-related manner. Serum concentrations of free Aur0101 were substantially lower than those of PF-06664178 and total antibody. No correlation of Trop-2 expression and objective response was observed, although Trop-2 overexpression was not required for study entry. The intermediate dose of 2.4 mg/kg appeared to be the highest tolerated dose, but this was not fully explored as the study was terminated early due to excess toxicity. Conclusion PF-06664178 showed toxicity at high dose levels with modest antitumor activity. Neutropenia, skin rash and mucosal inflammation were dose limiting toxicities. Findings from this study may potentially aid in future antibody drug conjugate design and trials.

Microleakage of Class I and II Composite Resin Restorations Using a Sonic-resin Placement System

OBJECTIVES

To determine microleakage of posterior Class I and II restorations using the SonicFill composite resin system.

METHODS AND MATERIALS

Eighty previously extracted third molars were randomly assigned to four preparation/restoration groups (n=20): Group A: Class I preparations restored with SonicFill system/bulk fill; Group B: Class II preparations restored with SonicFill system/bulk fill; Group C: Class I preparations restored with Herculite Ultra composite resin/incremental technique; and Group D: Class II preparations restored with Herculite Ultra composite resin/incremental technique. Class I preparations were approximately 3.0 mm in width buccolingually and 3.0 mm in depth. Class II preparations were approximately 3.0 mm in width buccolingually, 1.5 mm in axial depth, and 4.0 mm in gingival depth. In all groups, the enamel and dentin surfaces were conditioned with Kerr 37.5% phosphoric acid, followed by application of Optibond Solo Plus adhesive system. Following restoration, the specimens were thermocycled, immersed in methylene blue dye, and embedded in acrylic resin. Specimen blocks were sectioned in the mesiodistal direction, with marginal dye penetration (microleakage) examined using a 20× binocular microscope. Class I and II restoration microleakage was scored separately using a 0-3 ordinal ranking system. Statistical analyses were conducted using nonparametric testing at the p < 0.05 level of significance.

RESULTS

Significantly less microleakage was associated with both Class I restorative groups (A and C), SonicFill bulk fill and Herculite Ultra incremental fill, compared to the Class II restorative groups (B and D), SonicFill/bulk fill and Herculite Ultra/incremental fill.

CONCLUSIONS

According to the results of this study, the materials (SonicFill vs Herculite Ultra), C-factors, and insertion techniques (bulk vs incremental) did not appear to be significant influences with regard to marginal microleakage; however, the type of preparation cavity (Class I vs Class II) and the subsequent bonding surface (enamel vs dentin [cementum]) proved to be significant factors.

Abstract 3649: Significance of HIV viral load and CD4 count on Kaposi sarcoma in the era of highly active antiretroviral therapy

Background: Approximately 20% of patients with HIV will have Kaposi Sarcoma (KS) and about half will die within 3 months of diagnosis. Incidence and outcomes of KS have traditionally been linked to CD4 counts &lt;350. More recently, KS has been increasingly described in higher CD4 counts and variable presentations in the era of Highly-Active-Antiretroviral-Therapy (HAART). No studies have established the role of Viral Load (VL) on KS.

Objective: To determine the effect of CD4 count and HIV VL on KS presentation and outcomes.

Methods: Retrospective review of KS patients with HIV admitted over 12 years (2000-2012). KS patients without HIV infection were excluded. Patients were divided into 4 groups based on CD4 count (≥200 or 100,000 or &lt;100,000). Groups were analyzed with regards to KS severity (good vs poor risk), extent (soft tissue vs visceral), receipt of HAART and survival (6months). Statistical analysis was done via Chi-Square test.

Results: 43 patients were included. KS affected predominantly young (30-40yrs), male (93%) HIV patients with VL &gt;100,000 (85%) and CD4 counts 100,000 had a statistically significant increased incidence for visceral involvement (96%, p100,000 ((66.7% with good risk), increased survival (59.4% survived &gt;6months) and less use of HAART (20%). Although, these differences were statistically insignificant.

Conclusion: HIV VL of &gt;100,000 is correlated with increased severity and extent of KS. Though statistically insignificant, CD4 counts &lt;200 showed a trend for less severe disease and increased survival despite less use of HAART. Larger prospective studies are warranted to elucidate on these differences.

Citation Format: Gentry T. King, Shivani Garg. Significance of HIV viral load and CD4 count on Kaposi sarcoma in the era of highly active antiretroviral therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3649. doi:10.1158/1538-7445.AM2014-3649

Statin use and the development of bone metastasis in breast cancer patients

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Background: The Mevalonic Acid Pathway has been implicated in the promotion of a microenvironment suitable for establishment of bony metastasis from breast cancer. The statins, which act on this pathway, have been shown to have in-vitro anti-neoplastic activity against breast cancer. This study was designed to evaluate the association of statin use and development of bony metastasis in breast cancer patients. Methods: Medical records of patients treated for stage II-III breast cancer from 1999 to 2010 were retrospectively reviewed. Statin use was defined as medication use for at least 3 months in patients with no evidence of disease after initial diagnosis and treatment. The primary outcome was development of metastasis to bone. Secondary outcomes were overall survival, disease free survival and other sites of distant metastasis. Results: A total of 841 patients were included in the study of which 223 used statins. Both unadjusted and multivariate analysis adjusted for age, race, grade, stage , BRCA status, showed that patients on statins had a significantly lower incidence of metastasis to bone (OR 0.49, 95% CI 0.25-0.96, p=0.04). Adjusted analysis for other sites showed a trend towards decreased incidence of metastasis for statin users, but was not statistically significant (95% CI 0.39-1.08, p=0.10). Overall survival was increased in statin users with mean survival of 66.45 +/- 2.48 months versus non-users 58.78 +/ - 1.41 months (p=0.05). Statin users had significantly longer disease free survival with a mean of 63.65 +/- 2.49 months versus 53.96 +/- 1.42 months in non statin users (p=0.00). Conclusions: The use of statin drugs in patients with breast cancer was significantly associated with decreased incidence of metastasis to bone, but not to other distant sites. The role of statins in chemoprevention of bone metastasis should be further explored.

Infectious jejunitis with stricture after gastrojejunostomy

Although bacterial overgrowth has often been reported in postgastrectomy patients, inflammatory stricture near the surgical anastomosis is rare. We describe a 36-year-old woman with infectious jejunitis and subsequent jejunal stenosis after gastrojejunostomy.