Due to the COVID-19 pandemic. With a second wave just beginning, and considering that we are testing an immunosuppressant in patients with high risk for COVID-19 complications, we would not be able to re-start recruitment safely in the near future.

Prospective, randomized, double-blind, placebo-controlled, proof of concept study. Patients with first anterior wall STEMI will be randomized with 4±2 days after symptoms beginning to receive ddMTX-LDE at the dose of 40 mg/m2 IV or placebo-LDE weekly for 6 weeks. All study participants will additionally receive folic acid (5 mg po qd) once a week, one day after the study drug. The primary and main secondary endpoints will be analyzed by CMR 3±1 days and at 90±7 days after randomization.

Patients will undergo clinical and laboratory safety evaluations before each study drug administration and 90-day post-randomization. Safety evaluations will include assessment of adherence, side effects, safety laboratory tests, and existing medical conditions or planned procedures that might alter study drug dosing. These visits also include screening for the occurrence of clinical events of interest. An algorithm for drug suspension based on clinical and laboratory finding will be followed.

Pre-specified unblinded interim analyses by an independent investigator will be developed when 20% and 50% of the inclusions are reached.

Inflammation is extremely important in atherosclerosis and atherothrombosis pathophysiology. It is similarly important after acute myocardial infarction (AMI), with a special participation on healing response and, consequently, on left ventricular remodeling (LVR).

Early successful reperfusion is highly effective for limiting tissue necrosis and improving outcomes in AMI, but many of these patients show microcirculation dysfunction, phenomenon related to inflammation, leading to worse LVR. Additionally, inflammation may extend into the noninfarcted remote myocardium, which also contribute to adverse LVR.

As pointed out by Westman et al in a recent review publication, although infarct size correlates with the development of adverse LVR, some patients with relatively small infarcts have adverse LVR, while others with larger infarcts do not. Individual differences in the inflammatory response, perhaps in part genetically, epigenetically, environmentally, or pathogenically modulated, may contribute to this phenomenon.

The use of inflammatory biomarkers to predict risk, monitor treatments and guide therapy, has shown substantial potential for clinical applicability. Many studies in primary and secondary prevention of cardiovascular disease (CVD) showed that individuals with lower high sensitive C-reactive protein (hsCRP) have better clinical outcomes than those with higher levels.

So, anti-inflammatory therapies may be useful in preventing left ventricular dysfunction following AMI despite reperfusion and anti-remodeling treatments.

Among those, methotrexate (MTX) is an anti-inflammatory drug widely used in rheumatology and oncology. It reduces several inflammatory biomarkers including hs-CRP, interleukin 6 (IL-6), and tumor necrosis factor α (TNF α), without affecting negatively lipid, homocysteine or glucose levels, or blood pressure. Besides that, there are reports showing that MTX directly or indirectly releases endogenous anti-inflammatory adenosine, which could be especially useful in AMI patients.

In a systematic review with rheumatologic patients (including rheumatoid arthritis, psoriasis or polyarthritis), methotrexate was associated with 21% lower risk for total cardiovascular disease (CVD) and 18% lower risk for AMI, suggesting that a direct treatment of inflammation with this drug may reduce the risk of CVD in general.

To explore this option of treatment, the CIRT (Cardiovascular Inflammation Reduction Trial) was designed to evaluate the effect of methotrexate for secondary prevention on high risk patients with chronic stable coronary disease; this study is currently ongoing.

Although a potent anti-inflammatory drug, special attention must be given to methotrexate contraindications and numerous potential adverse effects. To overcome this issue, Moura et al developed a new formulation using a lipophilic derivative of methotrexate, ie, didodecyl methotrexate (ddMTX), associated with a lipid nanoemulsion (ddMTX-LDE).

Lipid nanoemulsions (LDE) that bind to low-density lipoprotein receptors was first developed and studied in the cancer scenario by Maranhão et al, who demonstrated that it concentrates the chemotherapeutic agents in tissues with low-density lipoprotein receptor overexpression, decreasing the toxicity of the treatment. The lipid nanoemulsion was already tested in patients with acute leukaemia, multiple myeloma and Hodgkin's and non-Hodgkin's lymphoma, suggesting that LDE is taken up by malignant cells with increased LDL receptors and that LDE, as drug-targeting vehicle, is suitable for patient use.

The ddMTX-LDE formulation was shown to be stable and uptake of the formulation by neoplastic cells in vitro was remarkably greater than of commercial methotrexate preparation, with much lower haematological toxicity. A study with intravenous ddMTX-LDE in rabbits showed anti-inflammatory effects on the synovia of arthritic joints that were clearly superior to the effects of a commercial methotrexate preparation. These results are conceivably due to greater methotrexate uptake by the joints when the drug is associated with a nanoemulsion. Another study with rabbits fed with high cholesterol diet showed that ddMTX-LDE reduced vessel inflammation and atheromatous lesions.

In Wistar rats with induced AMI treated with LDE without drug, commercial MTX and ddMTX-LDE, we demonstrated significant improvement in LVR along with infarct size reduction in the group ddMTX-LDE, in comparison with the groups commercial MTX and LDE without drug.

The above rational is the basis for the present project, where by the first time the role of LDE methotrexate formulation in humans, regarding LV remodelling post ST-segment elevation myocardial infarction (STEMI), will be tested.

Inclusion Criteria:

• Patients with type 1 STEMI, documented by: ischemic symptoms, new ST-elevation at the J-point in two contiguous leads (0.2 mV in men or 0.15 mV in women in leads V2-V3 and/or 0.1 mV in other leads or new left bundle branch block [LBBB]) and cardiac biomarkers (troponin and/or creatine kinase MB) with at least one value above the 99th percentile of the upper reference limit (URL).
• Submitted to any successful repercussion strategy (thrombolysis or angioplasty).
• Coronary angiography showing successful reperfusion therapy (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3 in the infarct-related artery) and residual obstruction in the infarct-related artery < 50%.
• Asymptomatic, without signs of clinical decompensation (heart rate < 100bpm, systolic blood pressure > 90mmHg, without vasoactive dor inotropic drugs, pulse oximetry > 95% with FiO2 21%).
• Signing the study informed consent.

Exclusion Criteria:

• History of AMI.
• Estimated glomerular filtration rate < 40 mL/min/1.73 m2.
• Contraindications for CMR: pacemaker, metallic devices, claustrophobia, obesity over 150 kg total weight.
• Prior history of chronic infectious disease, including tuberculosis, severe fungal disease, or known HIV positive.
• Chronic hepatitis B or C infection.
• Interstitial pneumonitis, bronchiectasis, or pulmonary fibrosis.
• Chest x-ray evidence in the past 12 months of interstitial pneumonitis, bronchiectasis, or pulmonary fibrosis.
• Prior history of nonbasal cell malignancy or myeloproliferative or lymphoproliferative disease within the past 5 years.
• White blood cell count <4000/mm3, hematocrit <32%, or platelet count <75000/mm3.
• Alanine aminotransferase levels (ALT) greater than 2-fold the upper limit of normal.
• History of alcohol abuse or unwillingness to limit alcohol consumption to < 4 drinks per week.
• Pregnancy or breastfeeding.
• Women of child bearing potential, even if currently using contraception.
• Men who plan to father children during the study period or who are unwilling to use contraception.
• Requirement for use of drugs that alter folate metabolism (trimethoprim/sulfamethoxazol) or reduce tubular excretion (probenecid) or known allergies to antibiotics making avoidance of trimethoprim impossible.
• Current indication for methotrexate therapy.
• Chronic use of oral steroid therapy or other immunosuppressive or biologic response modifiers.
• Known chronic pericardial effusion, pleural effusion, or ascites.
• New York Heart Association class III-IV congestive heart failure.
• Life expectancy of < 1 years.
• Active infection.

IPD can be shared after reasonable request approved by the study coordination.