Inclusion Criteria:
Inclusion Criteria- Study Entry
1. Subject must be able to understand and provide informed consent;
2. Is a candidate for a primary heart transplant (listed as a heart transplant only);
3. No desensitization therapy prior to transplant;
4. Agreement to use contraception: according to the FDA Office of Women's Health (http://www.fda.gov/birthcontrol), there are a number of birth control methods that are more than 80% effective.
* Female participants of child-bearing potential must consult with their physician and determine the most suitable method(s) from the above referenced list to be used for the duration of the study
* Those who choose oral contraception must agree to use a second form of contraception after administration of study drug for a period of 1 year after the last dose of study drug.
5. Mechanical support or investigational drug trials where the intervention ends at the time of transplantation are permitted;
6. In the absence of contraindication, vaccinations should be up to date for hepatitis B, influenza, pneumococcal, zoster, and Measles, Mumps, \& Rubella (MMR); and
7. Subjects from areas of endemic coccidioidomycosis are eligible for inclusion but must be treated prophylactically with fluconazole or itraconazole.
Inclusion Criteria - Randomization
1. Recipient of a primary heart transplant;
2. Negative virtual crossmatch (according to local center criteria);
3. No desensitization therapy prior to transplant;
4. Female subjects of childbearing potential must have a negative pregnancy test (serum or urine) prior to randomization; and
5. Agreement to use contraception: according to the FDA Office of Women's Health (http://www.fda.gov/birthcontrol), there are a number of birth control methods that are more than 80% effective.
* Female participants of child-bearing potential must consult with their physician and determine the most suitable method(s) from the above referenced list to be used for the duration of the study
* Those who choose oral contraception must agree to use a second form of contraception after administration of study drug for a period of 1 year after the last dose of study drug.
6. Negative SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) test result performed within 48 hours of transplant (SARS-CoV-2 is the virus that causes COVID-19)
Exclusion Criteria:
Exclusion Criteria Study Entry
1. Inability or unwillingness of a participant to give written informed consent or comply with study protocol;
2. Candidate for a multiple solid organ or tissue transplants;
3. Prior history of organ or cellular transplantation requiring ongoing systemic immunosuppression;
4. Currently breast-feeding a child or plans to become pregnant during the timeframe of the study follow up period;
5. History of severe allergic and/or anaphylactic reactions to humanized or murine monoclonal antibodies;
6. Known hypersensitivity to tocilizumab (Actemra®);
7. Previous treatment with tocilizumab (Actemra®);
8. Human Immunodeficiency Virus (HIV) positive;
9. Hepatitis B surface antigen positive;
10. Hepatitis B core antibody positive;
11. Hepatitis C virus antibody positive (anti-HCV Ab+) who are either untreated or, have failed to demonstrate sustained viral remission for more than 12 months (after anti-viral treatment);
12. Recipient of a Hepatitis C virus nucleic acid test (NAT) positive donor organ;
13. Subjects must be tested for latent TB infection (LTBI) within a year prior to transplant:
--Subjects with a positive test for LTBI must complete appropriate therapy for LTBI.
---A Subject is considered eligible only if they have a negative test for LTBI within one year prior to transplant OR
\---- if they have completed appropriate LTBI therapy within one year prior to transplant.
14. Subjects with a previous history of active Tuberculosis (TB);
15. Subjects with a history of splenectomy;
16. Known active current viral, fungal, mycobacterial or other infections not including (left ventricular assist device \[LVAD\]) driveline infections;
17. History of malignancy less than 5 years in remission.
--Any history of adequately treated in-situ cervical carcinoma, low grade prostate carcinoma, or adequately treated basal or squamous cell carcinoma of the skin will be permitted.
18. History of hemolytic-uremic syndrome/ thrombotic thrombocytopenia purpura;
19. History of demyelinating disorders such as:
* multiple sclerosis,
* chronic inflammation,
* demyelinating polyneuropathy.
20. History of gastrointestinal perforations, active inflammatory bowel disease or diverticulitis;
21. Any previous treatment with alkylating agents such as chlorambucil or, total lymphoid irradiation;
22. Radiation therapy within 3 weeks before enrollment.
--Enrollment of subjects who require concurrent radiotherapy should be deferred until the radiotherapy is completed and 3 weeks have elapsed since the last date of therapy.
23. Subjects with a hemoglobin \<7.0gm/dL (last measurement within 7 days prior to transplant);
24. Subjects with a platelet count of less than 100,000/mm\^3 (last measurement within 7 days prior to transplant);
25. Subjects with an absolute neutrophil count (ANC) of less than 2,000/mm\^3 (last measurement within 7 days prior to transplant);
26. Subjects with Aspartate Aminotransferase (AST) or Alanine Aminotransferase (ALT) levels \>3 x Upper Limit of Normal (ULN);
27. Subjects who are administered or intended to be administered cytolytic or anti-cluster of differentiation 25 (CD25) monoclonal antibody agents as induction therapy in the immediate post-transplant period;
28. Intent to give the recipient a live vaccine within 30 days prior to randomization;
29. Past or current medical problems or findings from physical examination or laboratory testing that are not listed above, which, in the opinion of the investigator, may:
* pose additional risks from participation in the study,
* may interfere with the participant's ability to comply with study requirements, or
* that may impact the quality or interpretation of the data obtained from the study.
Exclusion Criteria - Randomization
1. Recipient of multiple solid organ or tissue transplants;
2. Recipient of ex vivo preserved hearts and hearts donated after cardiac death (DCD);
3. Currently breast-feeding a child or plans to become pregnant during the timeframe of the study follow up period;
4. History of severe allergic anaphylactic reactions to humanized or murine monoclonal antibodies;
5. Known hypersensitivity to tocilizumab (Actemra®);
6. Previous treatment with tocilizumab (Actemra®);
7. HIV positive;
8. Hepatitis B surface antigen positive;
9. Hepatitis B core antibody positive;
10. Hepatitis B negative transplant recipient that received a transplant from a hepatitis B core antibody positive donor;
11. HCV+ subject(s) who are either untreated or have failed to demonstrate sustained viral remission for more than 12 months after anti-viral treatment;
12. Recipient of a hepatitis C virus nucleic acid test (NAT) positive donor organ;
13. Subject's organ donor tests positive for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (SARS-CoV-2 is the virus that causes COVID-19).
14. Subjects with a previous history of active (TB);
15. Subjects must be tested for latent TB infection (LTBI) within a year prior to transplant:
--Subjects with a positive test for LTBI must complete appropriate therapy for LTBI.
---A Subject is considered eligible only if they have a negative test for LTBI within one year prior to transplant OR
\---- if they have completed appropriate LTBI therapy within one year prior to transplant.
16. Subjects with a history of splenectomy;
17. Known active current viral, fungal, mycobacterial or other infections, not including (left ventricular assist device \[LVAD\]) driveline infections;
18. History of malignancy less than 5 years in remission.
--Any history of adequately treated in-situ cervical carcinoma, low grade prostate carcinoma, or adequately treated basal or squamous cell carcinoma of the skin will be permitted.
19. History of hemolytic-uremic syndrome/ thrombotic thrombocytopenia purpura;
20. History of demyelinating disorders;
21. History of gastrointestinal perforations, active inflammatory bowel disease or diverticulitis;
22. Any previous treatment with alkylating agents such as chlorambucil, or with total lymphoid irradiation;
23. Radiation therapy within 3 weeks before randomization.
--Enrollment of subjects who require concurrent radiotherapy should be deferred until the radiotherapy is completed and 3 weeks have elapsed since the last date of therapy.
24. Subjects with a hemoglobin \<7.0gm/dL within 7 days prior to randomization;
25. Subjects with a platelet count of less than 100,000/mm\^3 within 7 days prior to randomization;
26. Subjects with an absolute neutrophil count (ANC) of less than 2,000/mm\^3 within 7 days prior to randomization;
27. Subjects with AST or ALT levels \>3 x ULN;
28. Subjects who are administered or intended to be administered cytolytic or anti- CD25 monoclonal antibody agents as induction therapy in the immediate post- transplant period;
29. Receipt of a live vaccine within 30 days prior to randomization;
30. Use of investigational drugs after transplantation;
31. Past or current medical problems or findings from physical examination or laboratory testing that are not listed above, which, in the opinion of the investigator,
* may pose additional risks from participation in the study,
* may interfere with the participant's ability to comply with study requirements, or
* that may impact the quality or interpretation of the data obtained from the study.
32. Subjects with known donor-specific antibody at the time of evaluation of antibodies for heart transplant surgery (within 6 months).
