Immunotherapy is a promising treatment strategy for cancer that has recently shown unprecedented survival benefits in selected patients. A number of immunomodulatory agents that target immune system checkpoints such as the cytotoxic T-lymphocyte antigen 4 (CTLA-4), the programmed death-1 (PD-1) or its ligand (PD-L1), have received regulatory approval for the treatment of multiple cancers including malignant melanoma, non-small cell lung cancer, renal cell carcinoma, classical Hodgkin lymphoma, and recurrent or metastatic head and neck squamous cell carcinoma. Nevertheless, a substantial proportion of patients treated with checkpoint inhibitors have little or no benefit while these treatments are costly and might have associated toxicities. Hence, the establishment of valid predictors of treatment response has become a priority. This review summarizes the current evidence around biomarkers of response to PD-1/PD-L1 inhibition, considering features related to the tumor and to the host immune system.

The treatment of prosthetic joint infections caused by methicillin-resistant Staphylococcus aureus (MRSA) continues to be a challenge for the clinician. The aim of this study was to evaluate the efficacies of daptomycin at usual and high doses (equivalent to 6 and 10 mg/kg of body weight/day, respectively, in humans) and in combination with rifampin and to compare the activities to those of conventional anti-MRSA therapies. We used MRSA strain HUSA 304, with the following MICs and minimal bactericidal concentrations (MBCs), respectively: daptomycin, 1 g/ml and 4 g/ml; vancomycin, 2 g/ml and 4 g/ml; linezolid, 2 g/ml and >32 g/ml; and rifampin, 0.03 g/ml and 0.5 g/ml. In time-kill curves, only daptomycin and its combinations with rifampin achieved a bactericidal effect in log and stationary phases. For in vivo studies, we used a rat foreign-body infection model. Therapy was administered for 7 days with daptomycin at 100 mg/kg/day and 45/mg/kg/day, vancomycin at 50 mg/kg/12 h, rifampin at 25 mg/kg/12 h, and linezolid at 35 mg/kg/12 h, and each antibiotic was also combined with rifampin. Among monotherapies, daptomycin at 100 mg/kg/day and rifampin performed better than vancomycin and linezolid. In combination with rifampin, both dosages of daptomycin were significantly better than all other combinations, but daptomycin at 100 mg/kg/day plus rifampin achieved better cure rates at day 11 (P < 0.05) than daptomycin at 45 mg/kg/day plus rifampin. Resistant strains were found in monotherapies with rifampin and daptomycin at 45 mg/kg/day. In conclusion, daptomycin at high doses was the most effective monotherapy and also improved the efficacy of the combination with rifampin against foreign-body infections by MRSA. Clinical studies should confirm whether this combination may be considered the first-line treatment for foreign-body infections by MRSA in humans.

Since the currently approved dose of daptomycin (6 mg/kg of body weight/day) has been associated with clinical failures and resistance development, higher doses for some difficult-to-treat infections are being proposed. We studied the efficacy of daptomycin at high doses (equivalent to 10 mg/kg/day in humans) and compared it to that of reference and alternative treatments in a model of foreign-body infection with methicillin (meticillin)-resistant Staphylococcus aureus. In vitro studies were conducted with bacteria in the log and stationary phases. For the in vivo model, therapy with daptomycin at 100 mg/kg/day, vancomycin at 50 mg/kg/12 h, rifampin (rifampicin) at 25 mg/kg/12 h, or linezolid at 35 mg/kg/12 h was administered for 7 days. Antibiotic efficacy was evaluated using either bacteria from tissue cage fluids or those attached to coverslips. We screened for the emergence of linezolid-and rifampin-resistant strains and analyzed the surviving population from the daptomycin-treated group. Only daptomycin was bactericidal in both the log-and stationary-phase studies. Daptomycin (decrease in the log number of CFU per milliliter of tissue cage fluid, 2.57) and rifampin (decrease, 2.6 log CFU/ml) were better (P < 0.05) than vancomycin (decrease, 1.1 log CFU/ml) and linezolid (decrease, 0.9 log CFU/ml) in the animal model. Rifampin-resistant strains appeared in 60% of cases, whereas no linezolid resistance emerged. No daptomycin-resistant subpopulations were detected at frequencies of 10 ؊7 or higher. In conclusion, daptomycin at high doses proved to be as effective as rifampin, and the two were the most active therapies for this experimental foreign-body infection. These high doses ensured a profile of safety from the development of resistance.Daptomycin is a lipopeptide drug with bactericidal activity toward methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) in a concentration-dependent manner (27,32). It is currently approved for use at 4 mg/kg of body weight/day for skin and soft-tissue infections (1) and at 6 mg/kg/day for bacteremia and right-side endocarditis (12,14).In recent years, reports of clinical failures and the emergence of resistant strains following daptomycin treatment have raised great concern (6, 18, 31). As a result, higher doses of daptomycin are being proposed as an alternative for some difficult-to-treat infections such as complicated bacteremia and endocarditis. Recently, doses of 10 mg/kg/day were studied using an in vitro model of staphylococcal endocarditis, with the results being promising in terms of efficacy and resistance prevention (25, 26). To date, clinical experience with the activity of the drug at doses higher than 6 mg/kg/day is limited (15, 28), whereas good safety and tolerance profiles for daptomycin at up to 12 mg/kg/day in volunteers have been reported (4).Foreign-body infections are difficult to treat because of the presence of bacterial biofilm and tolerance to antibiotics (10,39). MRSA is commonly involved in such infections, and daptomycin may be a pro...

The efficacy of daptomycin, imipenem, or rifampin with fosfomycin was evaluated and compared with that of daptomycin-rifampin in a tissue cage model infection caused by methicillin-resistant Staphylococcus aureus (MRSA). Strain HUSA 304 was used. The study yielded the following results for MICs (in g/ml): fosfomycin, 4; daptomycin, 1; imipenem, 0.25; and rifampin, 0.03. The study yielded the following results for minimum bactericidal concentration (MBC) (in g/ml): fosfomycin, 8; daptomycin, 4; imipenem, 32; and rifampin, 0.5. Daptomycin-rifampin was confirmed as the most effective therapy against MRSA foreign-body infections. Fosfomycin combinations with high doses of daptomycin and rifampin were efficacious alternative therapies in this setting. Fosfomycin-imipenem was relatively ineffective and did not protect against resistance. The results of animal tissue cage infection models (1, 2) support the use of the combination daptomycin-rifampin as the reference treatment in patients with difficult-to treat foreign-body infections (FBI) caused by methicillin-resistant Staphylococcus aureus (MRSA).However, if daptomycin or rifampin cannot be administered in clinical practice, recent experimental and clinical results propose fosfomycin as a potential alternative, always in combined therapies, to prevent resistance (3-6). Among these combined therapies, the fosfomycin-beta-lactam combination showed enhanced efficacy (7-10), even though the use of beta-lactams against MRSA is discouraged.We tested the efficacy of fosfomycin combined with standard and high doses of daptomycin (equivalent to 6 and 10 mg/kg of body weight/day in humans, respectively), imipenem, or rifampin in comparison with the reference treatment (daptomycin-rifampin) in a tissue cage model of MRSA infection.MRSA strain HUSA 304 (ATCC BAA-39) was used for all in vitro and in vivo studies. MICs and minimal bactericidal concentrations (MBCs) for bacteria in the log phase (inoculum of 10 5 CFU/ml) were determined using standard recommendations (11), and MBCs for bacteria in the log phase at a higher inoculum (10 8 CFU/ml) and in the stationary phase were determined using methodology described elsewhere (12, 13). The results are presented in Fig. 1.Kill curves were also determined in the log phase (inocula of 10 5 CFU/ml and 10 8 CFU/ml) and in the stationary phase using methodology described elsewhere (12,14). Fosfomycin and rifampin alone showed similar behavior and were bactericidal only with the standard inoculum adjusted to 10 5 CFU/ml. Their efficacy was altered by inoculum size, stationary phase, and emergence of resistance; however, both showed a notable final killing of 2 log CFU/ml in the stationary phase. Imipenem had bactericidal activity only with low inocula but with an MBC as high as 32 g/ml. Corroborating previous reports (15), daptomycin was the only drug with bactericidal activity in the log and stationary phases. The results of some combinations are shown in Fig. 1. To our knowledge, the activity of these combinations in the stationary ph...

Afghanistan has made progress moving closer to eliminating polio. The program struggles to reach all children because of management and accountability problems in the field, inaccessible populations, and inadequate social mobilization. Consequently, too many children are missed during SIAs. Afghanistan adopted a national emergency action plan in 2012 to address these issues, but national elimination will require consistent and complete implementation of proven strategies.

Despite the use of daptomycin alone at high doses (greater than 6 mg/kg of body weight/day) against difficult-to-treat infections, clinical failures and resistance appeared. Recently, the combination daptomycin-cloxacillin showed enhanced efficacy in clearing bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to evaluate the efficacy of daptomycin at usual and high doses (equivalent to 6 and 10 mg/kg/day in humans, respectively) in combination with cloxacillin in a rat tissue cage infection model by MRSA and to compare its efficacy to that of daptomycin-rifampin. We used MRSA strain ATCC BAA-39. In the log-and stationary-phase kill curves, daptomycin-cloxacillin improved the bactericidal activity of daptomycin, especially in log phase. For in vivo studies, therapy was administered intraperitoneally for 7 days with daptomycin at 100 mg/kg/day and 45/mg/kg/day (daptomycin 100 and daptomycin 45), daptomycin 100-cloxacillin at 200 mg/kg/12 h, daptomycin 45-cloxacillin, and daptomycin 100-rifampin at 25 mg/kg/12 h. Daptomycin-rifampin was the best therapy (P < 0.05). Daptomycin 45 was the least effective treatment and did not protect against the emergence of resistant strains. There were no differences between the two dosages of daptomycin plus cloxacillin in any situation, and both protected against resistance. The overall effect of the addition of cloxacillin to daptomycin was a significantly greater cure rate (against adhered bacteria) than that for daptomycin alone. In conclusion, daptomycin-cloxacillin enhanced modestly the in vivo efficacy of daptomycin alone against foreignbody infection by MRSA and was less effective than daptomycin plus rifampin. The benefits of adding cloxacillin to daptomycin should be especially evaluated against infections by rifampin-resistant MRSA and for protection against the emergence of daptomycin nonsusceptibility.

BackgroundRenal epithelioid angiomyolipomas (EAML) are rare tumors with aggressive behavior. EAML can be sporadic or develop within the tuberous sclerosis complex syndrome, where mutations of TSC1 or TSC2 genes (critical negative regulators of mTOR Complex 1) result in an increased activation of mTOR pathway. Optimal EAML treatment, including mTOR inhibitors, remains undetermined.Case presentationHere we present the case of a young adult with a renal EAML that after radical nephrectomy developed metastases, first in liver and then in lumbar vertebrae. After complete surgical resection of these lesions, liver recurrence was detected, this time with incomplete surgical resection. After finding a new liver lesion, systemic treatment with sirolimus started. The patient exhibited a complete and durable response to this drug, being disease free at the time of publication, after 36 months of treatment. Targeted next generation sequencing (NGS) of MTOR, TSC1 and TSC2 genes in the primary tumor, metastasis and blood of the patient, revealed one inactivating TSC2 mutation (c.2739dup; p.K914*) in the tumor cells. Immunohistochemistry revealed decreased TSC2 protein content and increased phospho-S6 in the tumor cells, demonstrating mTOR pathway activation.ConclusionNGS on an EAML patient with an extraordinary response to sirolimus uncovered TSC2 inactivation as the mechanism for the response. This study supports NGS as a useful tool to identify patients sensitive to mTOR inhibitors and supports the treatment of malignant EAML with these drugs.

Daptomycin at standard doses, and especially at high doses, may be a useful alternative for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis.