Minoclonal Antibodies Against Clostridium Difficile

While probiotics may be a good choice for Clostridium difficile prevention, antibiotics may be required for infection.  Antibiotic resistance is becoming a problem.  Here is an interesting study on monoclonal antibody therapy for this difficult infection.  Abstract:

Background Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients. Recurrences are common after antibiotic therapy. Actoxumab and bezlotoxumab are human monoclonal antibodies against C. difficile toxins A and B, respectively. Methods We conducted two double-blind, randomized, placebo-controlled, phase 3 trials, MODIFY I and MODIFY II, involving 2655 adults receiving oral standard-of-care antibiotics for primary or recurrent C. difficile infection. Participants received an infusion of bezlotoxumab (10 mg per kilogram of body weight), actoxumab plus bezlotoxumab (10 mg per kilogram each), or placebo; actoxumab alone (10 mg per kilogram) was given in MODIFY I but discontinued after a planned interim analysis. The primary end point was recurrent infection (new episode after initial clinical cure) within 12 weeks after infusion in the modified intention-to-treat population. Results In both trials, the rate of recurrent C. difficile infection was significantly lower with bezlotoxumab alone than with placebo (MODIFY I: 17% [67 of 386] vs. 28% [109 of 395]; adjusted difference, -10.1 percentage points; 95% confidence interval [CI], -15.9 to -4.3; P<0.001; MODIFY II: 16% [62 of 395] vs. 26% [97 of 378]; adjusted difference, -9.9 percentage points; 95% CI, -15.5 to -4.3; P<0.001) and was significantly lower with actoxumab plus bezlotoxumab than with placebo (MODIFY I: 16% [61 of 383] vs. 28% [109 of 395]; adjusted difference, -11.6 percentage points; 95% CI, -17.4 to -5.9; P<0.001; MODIFY II: 15% [58 of 390] vs. 26% [97 of 378]; adjusted difference, -10.7 percentage points; 95% CI, -16.4 to -5.1; P<0.001). In prespecified subgroup analyses (combined data set), rates of recurrent infection were lower in both groups that received bezlotoxumab than in the placebo group in subpopulations at high risk for recurrent infection or for an adverse outcome. The rates of initial clinical cure were 80% with bezlotoxumab alone, 73% with actoxumab plus bezlotoxumab, and 80% with placebo; the rates of sustained cure (initial clinical cure without recurrent infection in 12 weeks) were 64%, 58%, and 54%, respectively. The rates of adverse events were similar among these groups; the most common events were diarrhea and nausea. Conclusions Among participants receiving antibiotic treatment for primary or recurrent C. difficile infection, bezlotoxumab was associated with a substantially lower rate of recurrent infection than placebo and had a safety profile similar to that of placebo. The addition of actoxumab did not improve efficacy. (Funded by Merck; MODIFY I and MODIFY II ClinicalTrials.gov numbers, NCT01241552 and NCT01513239 .).

Bezlotoxumab seems to be a promising therapeutic agent against this problem infection.

Immune Checkpoint Inhibitor Therapy Biomarkers

Immune checkpoints dampen the immune system’s ability to detect and fight cancer; thus, inhibits of such checkpoints, usually antibodies to checkpoint factors, have utility for immunotherapy against cancer.  Clinical success has been varied, and it would be helpful to identify biomarkers to ascertain what patients would most benefit by this therapeutic approach.  This study identifies some prospective markers that require more conformation.  Abstract:

Immune checkpoint blockers (ICB) have become pivotal therapies in the clinical armamentarium against metastatic melanoma (MMel). Given the frequency of immune related adverse events and increasing use of ICB, predictors of response to CTLA-4 and/or PD-1 blockade represent unmet clinical needs. Using a systems biology-based approach to an assessment of 779 paired blood and tumor markers in 37 stage III MMel patients, we analyzed association between blood immune parameters and the functional immune reactivity of tumor-infiltrating cells after ex vivo exposure to ICB. Based on this assay, we retrospectively observed, in eight cohorts enrolling 190 MMel patients treated with ipilimumab, that PD-L1 expression on peripheral T cells was prognostic on overall and progression-free survival. Moreover, detectable CD137 on circulating CD8+ T cells was associated with the disease-free status of resected stage III MMel patients after adjuvant ipilimumab + nivolumab (but not nivolumab alone). These biomarkers should be validated in prospective trials in MMel. The clinical management of metastatic melanoma requires predictors of the response to checkpoint blockade. Here, the authors use immunological assays to identify potential prognostic/predictive biomarkers in circulating blood cells and in tumor-infiltrating lymphocytes from patients with resected stage III melanoma.

Against Colitis And Cancer

Chronic inflammation of the colon can increase risk for cancer; an antibody to a pro-inflammatory mediator can reduce inflammation in a mouse model, reducing cancer risk through the modulation of important cancer- related signaling pathways that can be affected by inflammation.  This is a promising therapeutic approach.  Abstract:

The association between chronic inflammation and cancer has long been recognized. The inflammatory bowel disease ulcerative colitis frequently progresses to colon cancer; however, the underlying mechanism is still unclear. S100a9 has been emerged as an important pro-inflammatory mediator in acute and chronic inflammation, and the aberrant expression of S100a9 also contributes to tumorigenic processes such as cell proliferation, angiogenesis, metastasis, and immune evasion. We previously revealed that S100a8 and S100a9 are highly activated and play an important role in the process of colitis-associated carcinogenesis, which suggests an attractive therapeutic target for ulcerative colitis and related colon cancer. Here, we report that administration of a neutralizing anti-S100a9 antibody significantly ameliorated dextran sulfate sodium (DSS)-induced colitis and accompanied by diminished cellular infiltrate of innate immunity cells (macrophages, neutrophils, and dendritic cells) and production of pro-inflammatory cytokines (Tnfα, Il1β, Ifnγ, Il6, Il17a, Il23a, Il4, and Il12a). The protective effect of anti-S100a9 antibody treatment was also observed in azoxymethane (AOM)/DSS-induced colitis-associated cancer (CAC) mouse model. The inflammatory response, tumor cell proliferation, and immune cells infiltration in the colon tissues were suppressed by anti-S100a9 antibody. Gene expression profiling showed that key pathways known to be involved in CAC development, such as Wnt signaling pathway, PI3K-Akt signaling pathway, cytokine-cytokine receptor interaction, and ECM-receptor interaction pathway, were suppressed after treatment with anti-S100a9 antibody in CAC mice. In view of the protective effect of neutralizing anti-S100a9 antibody against DSS-induced colitis and AOM/DSS-induced CAC in mouse model, this study suggests that anti-S100a9 antibody may provide a novel therapeutic approach to treat ulcerative colitis and may decrease the risk for developing CAC.

Expanding The Immunotherapy Arsenal

A review on cancer immunotherapy is here, including the interesting approach of viruses that target and destroy tumor cells. Abstract:

Malignant cells have the capacity to rapidly grow exponentially and spread in part by suppressing, evading, and exploiting the host immune system. Immunotherapy is a form of oncologic treatment directed towards enhancing the host immune system against cancer. In recent years, manipulation of immune checkpoints or pathways has emerged as an important and effective form of immunotherapy. Agents that target cytotoxic T lymphocyte-associated molecule-4 (CTLA-4), programmed cell death receptor-1 (PD-1), and programmed cell death ligand-1 (PD-L1) are the most widely studied and recognized. Immunotherapy, however, extends beyond immune checkpoint therapy by using new molecules such as chimeric monoclonal antibodies and antibody drug conjugates that target malignant cells and promote their destruction. Genetically modified T cells expressing chimeric antigen receptors are able to recognize specific antigens on cancer cells and subsequently activate the immune system. Native or genetically modified viruses with oncolytic activity are of great interest as, besides destroying malignant cells, they can increase anti-tumor activity in response to the release of new antigens and danger signals as a result of infection and tumor cell lysis. Vaccines are also being explored, either in the form of autologous or allogenic tumor peptide antigens, genetically modified dendritic cells that express tumor peptides, or even in the use of RNA, DNA, bacteria, or virus as vectors of specific tumor markers. Most of these agents are yet under development, but they promise to be important options to boost the host immune system to control and eliminate malignancy. In this review, we have provided detailed discussion of different forms of immunotherapy agents other than checkpoint-modifying drugs. The specific focus of this manuscript is to include first-in-human phase I and phase I/II clinical trials intended to allow the identification of those drugs that most likely will continue to develop and possibly join the immunotherapeutic arsenal in a near future.

Monoclonal Antibodies For Severe Asthma

By Adenosine - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9659630

Monoclonal antibodies are being used to treat many diseases, particularly cancer, and in this paper we see their utility for treating severe asthma. Different types of antibodies can be used dependent upon asthma type and characteristics, suggesting hope for people with the more serious forms of this disease.  Abstract:

Among the monoclonal antibodies (mAbs) developed for severe asthma treatment, three have already been marketed. Omalizumab was the first, more than 10 years ago; today, mepolizumab and reslizumab are also available in the European Union and the US. Omalizumab blocks free immunoglobulin E (IgE), mepolizumab and reslizumab block an interleukin (IL-5). In the near future, dupilumab and benralizumab are expected to emerge as two new alternatives. Benralizumab blocks the receptor for IL-5 (IL5-Rα) and has a direct cytotoxic effect on eosinophils, and dupilumab blocks the α-unit of the heterodimeric receptor for IL-4 and IL-13 (IL-4Rα); as a result, dupilumab can block both IL-4 and IL-13. The purpose of this manuscript is to present the pathophysiology of some immunological aspects of severe asthma, describe the adaptive and innate immunity arms as well as their interrelations (stressing the subordination of the adaptive arm to the innate arm), outline the pharmacologic effects of these mAbs, clarify the overlapping effects of the different mAbs, and discuss the differences between mAbs based on their target molecules. Based on the data presented, I propose omalizumab for patients with an allergic phenotype regardless of their peripheral eosinophilic count, and anti-IL-5 as an alternative in allergic patients with blood eosinophilia in which omalizumab has failed; anti-IL5 for patients with an eosinophilic phenotype and omalizumab as an alternative in patients in whom anti-IL5 fails and IgE ≥30 IU/mL (compassionate use). Omalizumab is also proposed for patients with severe chronic asthma allergic to seasonal allergens.

Antibodies To Watch In 2018

For those of you who like to keep track of such things, here is a list of clinically relevant antibodies that may prove therapeutically useful in 2018 and beyond. Abstract:

The pace of antibody therapeutics development accelerated in 2017, and this faster pace is projected to continue through 2018. Notably, the annual number of antibody therapeutics granted a first approval in either the European Union (EU) or United States (US) reached double-digits (total of 10) for the first time in 2017. The 10 antibodies granted approvals are: brodalumab, dupilumab, sarilumab, guselkumab, benralizumab, ocrelizumab, inotuzumab ozogamicin, avelumab, duvalumab, and emicizumab. Brodalumab, however, had already been approved in Japan in 2016. As of December 1, 2017, nine antibody therapeutics (ibalizumab, burosumab, tildrakizumab, caplacizumab, erenumab, fremanezumab, galcanezumab, romosozumab, mogamulizumab) were in regulatory review in the EU or US, and regulatory actions on their marketing applications are expected by the end of 2018. Based on company announcements and estimated clinical study primary completion dates, and assuming the study results are positive, marketing applications for at least 12 antibody therapeutics that are now being evaluated in late-stage clinical studies may be submitted by the end of 2018. Of the 12 candidates, 8 are for non-cancer indications (lanadelumab, crizanlizumab, ravulizumab, eptinezumab, risankizumab, satralizumab, brolucizumab, PRO140) and 4 are for cancer (sacituzumab govitecan, moxetumomab pasudotox, cemiplimab, ublituximab). Additional antibody therapeutics to watch in 2018 include 19 mAbs undergoing evaluation in late-stage studies with primary completion dates in late 2017 or during 2018. Of these mAbs, 9 are for non-cancer indications (lampalizumab, roledumab, emapalumab, fasinumab, tanezumab, etrolizumab, NEOD001, gantenerumab, anifrolumab) and 10 are for cancer indications (tremelimumab, isatuximab, BCD-100, carotuximab, camrelizumab, IBI308, glembatumumab vedotin, mirvetuximab soravtansine, oportuzumab monatox, L19IL2/L19TNF). Positive clinical study results may enable marketing application submissions in 2018. Brief summaries of these antibody therapeutics are provided in this installment of the 'Antibodies to watch' article series.

Nivolumab Vs. Ipilimumab For Melanoma

Nivolumab and ipilimumab are monoclonal antibodies useful in the treatment of advanced melanoma; these target "immune checkpoints" - the activity that suppresses immune system recognition of cancer.  Thus, these antibodies inhibit the checkpoints and allow the patient's immune system to better fight the cancer.  It seems that nivolumab is superior to ipilimumab in at least this study. Abstract:

Background Nivolumab and ipilimumab are immune checkpoint inhibitors that have been approved for the treatment of advanced melanoma. In the United States, ipilimumab has also been approved as adjuvant therapy for melanoma on the basis of recurrence-free and overall survival rates that were higher than those with placebo in a phase 3 trial. We wanted to determine the efficacy of nivolumab versus ipilimumab for adjuvant therapy in patients with resected advanced melanoma. Methods In this randomized, double-blind, phase 3 trial, we randomly assigned 906 patients (≥15 years of age) who were undergoing complete resection of stage IIIB, IIIC, or IV melanoma to receive an intravenous infusion of either nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks (453 patients) or ipilimumab at a dose of 10 mg per kilogram every 3 weeks for four doses and then every 12 weeks (453 patients). The patients were treated for a period of up to 1 year or until disease recurrence, a report of unacceptable toxic effects, or withdrawal of consent. The primary end point was recurrence-free survival in the intention-to-treat population. Results At a minimum follow-up of 18 months, the 12-month rate of recurrence-free survival was 70.5% (95% confidence interval [CI], 66.1 to 74.5) in the nivolumab group and 60.8% (95% CI, 56.0 to 65.2) in the ipilimumab group (hazard ratio for disease recurrence or death, 0.65; 97.56% CI, 0.51 to 0.83; P<0.001). Treatment-related grade 3 or 4 adverse events were reported in 14.4% of the patients in the nivolumab group and in 45.9% of those in the ipilimumab group; treatment was discontinued because of any adverse event in 9.7% and 42.6% of the patients, respectively. Two deaths (0.4%) related to toxic effects were reported in the ipilimumab group more than 100 days after treatment. Conclusions Among patients undergoing resection of stage IIIB, IIIC, or IV melanoma, adjuvant therapy with nivolumab resulted in significantly longer recurrence-free survival and a lower rate of grade 3 or 4 adverse events than adjuvant therapy with ipilimumab. (Funded by Bristol-Myers Squibb and Ono Pharmaceutical; CheckMate 238 ClinicalTrials.gov number, NCT02388906 ; Eudra-CT number, 2014-002351-26 .).

Why not combine them?  Someone has thought of that, and it works well.

More on checkpoints here.