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Cardio-Oncology, Meet Your New Neighbor: Immunology

In this AHA session, an international group of physician scientists discussed ways to mitigate immune checkpoint inhibitor (ICI) induced myocarditis and future therapies. The session, moderated by Dr. Sakima Smith MD, MPH, FAHA (from THE Ohio State), and Dr. Doug Tiley highlighted studies by Drs. Burkhard Ludewig, DVM, Dr. Han Zhu, MD, Dr. Alcaide, PhD, Dr. Peter Liu, MD and Dr. Joe-Elie Salem, MD, PhD. The talk began with presenting the problem, basic-science T-cell mechanisms including involvement of microbiota, and ended with a possible targeted therapy, Abatacept. This is a hot topic in the cardio-oncology world considering the high mortality in those affected (up to 50%!) [1].

Source: Cardio-Oncology, Meet Your New Neighbor: Immunology| American Heart

ICIs (eg. ipilimumab, pembrolizumab) are effective targeted therapies in patients with PDL-1/PD-1 expression on tumor cells. Many cancer phenotypes are FDA approved for treatment which includes melanoma, renal cell carcinoma, non-small-cell lung cancer, Hodgkin lymphoma, and more[2]. Although these agents have shown to extend cancer survivorship[3] , they have inadvertent side effects that can lead to myocarditis and cardiomyopathy. ICIs act by “releasing the brake” of T cell immune proliferation. These monoclonal antibodies block PD1/PDL-1 ligands/receptors and allow for T cells to bind to tumor cells leading to reduced tumor burden[3]. Understanding the mechanism for ICI induced myocarditis is partially based on PDL1 knockout mice[4]. Unfortunately, there is cross-reactivity that occurs via binding to cardiac antigens (eg. myosin) leading to the inflammatory response[4].

Dr. Zhu informed us that the risk of this effect includes dual ICI treatment. In addition, early identification is key, considering 50% mortality. Patients may have a drop in their ejection fraction (EF), but have other signs of cardiac injury including brady and tachyarrhythmias. She highlighted that our current data is from FDA sponsored pharmacovigilance databases collected by Dr. Javid Moslehi, who is a pioneer and leading investigator on this subject. A registry created by Dr. Tom Neilan’s lab at Massachusetts General Hospital demonstrated an increased risk of MI and stroke after treatment with ICI[5]. Her group at Stanford along with renowned Dr. Ronald Witteles is using biobanking to identify patients with autoimmune myocarditis and controls to conduct downstream high-throughput immune repertoire analysis. Dr. Alcaide supplemented this talk by adding a novel mechanism. She discussed that reactive oxygen species (ROS) play a role in triggering downstream T cell expansion in the heart. Therefore, there may be a role in anti-oxidant therapy to reduce T cell response. Dr. Liu acknowledged our current pandemic and discussed the added risk of inflammation in the setting of concomitant COVID19 viral infection associated with myocarditis.

During this session, we learned about possible therapies to mitigate myocarditis. Dr. Ludewig discussed his teams work with an ICI mouse model. They explored T cell cross-reactivity that led to the lethality of the disease. There was a heart-gut connection! They found elevation of Bacteroides-specific CD4+ T cells in disease models which suggests that mimic peptides from commensal bacteria can promote inflammatory cardiomyopathy in genetically susceptible patients (those with HLA DQB1*03:01 polymorphisms) by showing increased reactivity against myosin 6 (MYH6) (cardiac antigen). His study suggests that the genetic susceptibility along with cross-reactivity antigens in the heart and potentially the intestine put patients at risk for fulminant myocarditis. Therefore, he proposed the use of antibiotics as a cardioprotective agent by blocking the cross-reactivity that leads to ICI induced myocarditis.

Source:  Ludewig: ‘Dangerous gut-heart liaison’| When it comes to matters of the heart, don’t always trust your gut/ Cruz et al. Microbiota-derived peptide mimics drive lethal inflammatory cardiomyopathy. Science 2019; 336, 881-886.

Dr. Joe Elie-Salem (making us jealous by Zooming in from Paris; Ca alors!) ended the session with the introduction of abatacept for therapeutic use in ICI induced myocarditis.  Corticosteroids are the mainstay of treatment; however steroid therapy is nonspecific and there are unintended off-target side effects. Specifically, there is a high association with concurrent myasthenia gravis-like syndrome with ICI myocarditis that presents a challenge with the use of steroids. Steroids can lead to an exacerbation of myasthenia crisis which can lead to significant respiratory failure[6].  Based on work with Dr. Moslehi, abatacept (a cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] agonist, they found that in anti-CTLA4 and Anti—PDL-1  treated disease mouse models, treatment with abatacept reduced myocarditis induced death. This agent will be further explored in a Phase II trial titled: ACHLYS-trial: Phase II trial testing abatacept for ICI-myocarditis.

The take-home points for this session include: 1) ICI used to treat many cancer phenotypes are associated with incident myocarditis with up to 50% mortality 2) Cross-reactivity with cardiac antigens leads to myocyte dysfunction and the clinical sequelae of this includes cardiomyopathy (not always!) and brady/tachyarrhythmias 3) Understanding predisposing immune variants and microbiota (Bacteroides- B. theta) related to immune response associated with this disease is key to identifying all the possible therapies including antibiotics 4) Abatacept is a known T cell immunomodulator and it has a potential role in treating ICI induced myocarditis; especially in those at risk for corticosteroid effects (eg. myasthenia gravis), which will be further explored in a clinical trial.

REFERENCE

  1. Ball, S., et al., Cardiovascular Toxicities of Immune Checkpoint Inhibitors: JACC Review Topic of the Week. J Am Coll Cardiol, 2019. 74(13): p. 1714-1727.
  2. Zhou, Y.W., et al., Immune Checkpoint Inhibitor-Associated Cardiotoxicity: Current Understanding on Its Mechanism, Diagnosis and Management. Front Pharmacol, 2019. 10: p. 1350.
  3. Ferris, R.L., et al., Nivolumab for Recurrent Squamous-Cell Carcinoma of the Head and Neck. N Engl J Med, 2016. 375(19): p. 1856-1867.
  4. Nishimura, H., et al., Autoimmune dilated cardiomyopathy in PD-1 receptor-deficient mice. Science, 2001. 291(5502): p. 319-22.
  5. Drobni, Z.D., et al., Association Between Immune Checkpoint Inhibitors with Cardiovascular Events and Atherosclerotic Plaque. Circulation, 2020.
  6. Xing, Q., et al., Myositis-myasthenia gravis overlap syndrome complicated with myasthenia crisis and myocarditis associated with anti-programmed cell death-1 (sintilimab) therapy for lung adenocarcinoma. Ann Transl Med, 2020. 8(5): p. 250.

“The views, opinions and positions expressed within this blog are those of the author(s) alone and do not represent those of the American Heart Association. The accuracy, completeness and validity of any statements made within this article are not guaranteed. We accept no liability for any errors, omissions or representations. The copyright of this content belongs to the author and any liability with regards to infringement of intellectual property rights remains with them. The Early Career Voice blog is not intended to provide medical advice or treatment. Only your healthcare provider can provide that. The American Heart Association recommends that you consult your healthcare provider regarding your personal health matters. If you think you are having a heart attack, stroke or another emergency, please call 911 immediately.”

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Bending the Curve for CV Disease- Precision or PolyPill?

Source: https://www.phri.ca/

Drs. Yusuf and Pais from the Population Health Research Institute in Ontario, Canada presented data from the International Polycap Study (TIPS)-3 study[1] as part of the Late-Breaking Science Session: Bending the Curve for CV Disease-Precision or PolyPill? at the AHA20 Scientific Sessions. The aim of this study was to try to simplify primary prevention via a ‘polypill’ (Polycap) for not only cardiovascular disease (CVD) but also conditions with similar risk profiles, such as breast cancer and osteoporosis. The polypill contains 3 blood pressure medications (hydrochlorothiazide (25mg), atenolol (100 mg), ramipril (10mg)) and a statin (simvastatin (40 mg). They are searching for a ‘magic bullet’ if you will, to reduce these chronic diseases with a high burden in the U.S and around the world. Precision medicine can be effective but is costly. The use of a polypill can help to reduce the curve of disease burden or at least shift it towards reducing the number of high cardiovascular risk people worldwide.

Source: Joseph et al. The International Polycap Study-3 (TIPS-3): Design, baseline characteristics and challenges in conduct. Am Heart J. 2018 206:72-79

This study enrolled 5,713 middle aged participants from 10 different countries (Including India, Tanzania, and Tunisia). With a 2x2x2 factorial design, randomized controlled trial investigators aimed to assess the effectiveness of PolyCap the ‘Polypill’.  Participants were eligible for the study if they did not have prior heart disease or stroke. Participants were excluded if they had any contraindications to the study medications, low and symptomatic  hypotension, history of malignancy, and inability to attend follow-up. There were three treatment arms. The participants were randomized to the polypill vs placebo. In addition, participants were also randomized to receive aspirin (75 mg) and vitamin D (60,000 IU monthly) each vs. placebo. The primary outcome was major cardiovascular disease (CVD) (CV death, non-fatal stroke, non-fatal MI), plus heart failure, resuscitated and cardiac arrest, or revascularization with evidence of ischemia in participants taking Polycap versus placebo. For the aspirin arm, the primary outcome was composite CV events ( CV death, MI or stroke) and cancer. For vitamin D arm, the primary outcome was risk of fractures in participants taking Vitamin D. The data presented at AHA2020 Scientific Sessions was for the Polypill with and without aspirin alone vs. placebo. This was an intention to treat analysis. Investigators also conducted a sensitivity analysis for those who were not able to adhere to medications and identified outcomes at 30 days in the active and placebo groups.

Source: Joseph et al. The International Polycap Study-3 (TIPS-3): Design, baseline characteristics and challenges in conduct. Am Heart J. 2018 206:72-79

After a follow-up time up to 5 years, the investigators enrolled a cohort of 53% women with intermediate CVD risk based on the IH (INTERHEART) risk score (1.5 % per year risk of CVD). For participants taking the Polypill vs. placebo, there was a significant mean reduction in systolic blood pressure by approximately 5 mm Hg and LDL-C by approximately 19 mg/dL. There was a 21% reduction in the primary outcome; however, overall mortality was not significantly different. The greatest reduction was seen with revascularization with a 60% reduction compared to the placebo. There was a reduction in cancer outcomes as well, but not significantly; this is likely related to low events. The bleeding risk profile was low. With the combination of aspirin and the Polypill, there was a 31 % risk reduction compared to placebo, aspirin alone, and the Polypill alone ( compared to 14% with aspirin vs. placebo alone)  in the composite primary outcome but no overall mortality benefit. This was mainly driven by a reduction in stroke. CVD death and cancer were significantly reduced by 30% compared to placebo. There was also a reduction with systolic blood pressure and LDL-C as seen with the Polypill alone. Aspirin alone did not show any difference with major/minor bleeding or GI bleeding likely related to having a run-in period and a lower dose of asa (75 mg). In both cases, the heart failure rate was higher in both groups but this was not significant with a wide confidence interval with low event. It is important to note that lifestyle modification teaching was also instituted and the reduction in outcomes is therefore contributed to both the medication and education.  One main issue was adherence to the medications (just two pills) up to 43%! This was in part due to COVID19 by the end of the study.  Per the sensitivity analysis, the outcomes of those with some adherence (<30 days) were still significantly lower than the placebo. Taking something for even a short period of time is better than nothing.

The authors highlight the significant limitation of non-adherence which can create a selection bias in the data. However,  if only half eligible people adhere to this regimen, 3-5 million CVD events can be avoided each year globally. They note that the challenge of adherence lies in social determinants of health, which have a great impact on CVD outcomes. More needs to be done to understand cost-effective ways to ‘bend the CVD curve’ by identifying effective implementation programs (including telehealth) to distribute this combination of medications.

References:

Joseph et al. The International Polycap Study-3 (TIPS-3): Design, baseline characteristics and challenges in conduct. Am Heart J. 2018 206:72-79