Inclusion Criteria:
* Biologic male or female, 18 to 70 years of age at the time of informed consent.
* Capable of and willing to provide signed informed consent (ICF); subject must sign ICF indicating that he or she understands the purpose of procedures required for the study and is willing to participate in the study. Consent is to be obtained prior to the initiation of any study-related tests or procedures that are not part of standard-of-care for the subject's disease.
* Willing and able to comply with the visits, treatments, procedures, laboratory tests, and other requirements according to the current protocol, with a high probability for adherence and completion of the study.
* Presensitized patient
1. Deceased kidney donor transplant candidate Broadly sensitized recipient on deceased donor waiting list: inclusion in the AM program (\>85% vPRA) for ≥24 months or inclusion in the ETKAS scheme and \>95% vPRA for ≥24 months, but not fulfilling the criteria in the AM program (panel reactivity includes specificities that are not acceptable by the local center; e.g. HLA antibodies with an MFI \>10.000 but no prior sensitizing event documented).
AND:
A dilution of the baseline serum obtained at screening by 1:100 must lead to a considerable decrease in HLA antibody MFI, with a decrease in vPRA levels by at least 1.0%.
OR
2. Living donor kidney transplant candidate Living donor transplant candidate with, according to local policy, unacceptable DSA against the scheduled donor and no option of kidney paired donation (KPD) transplantation, or within a KPD program with no transplant offer after 12 months of listing.
AND:
A dilution of the baseline serum obtained at screening by 1:100 must lead to a negative DSA result or to a considerable decrease in DSA MFI to permissive levels per local lab.
* Women of childbearing potential (WOCBP) must have a negative pregnancy test at screening using a highly sensitive pregnancy test. Women of childbearing potential and fertile men who are sexually active must agree to use a highly effective method of contraception (\<1% / year failure rate) during the study and for 150 days after the last dose of study drug. Women and men must agree not to donate eggs (ova, oocytes) or sperm, respectively, during the study and for 90 days after the last dose of study drug.
* Within 4 weeks prior to inclusion, participants should be up to date on all vaccinations recommended by the local country or regional public health authority, as determined by the Investigator.
Exclusion Criteria:
* Prior treatment with any therapy that is targeted to BCMA or any other CD3-redirecting drug.
* Treatment with prohibited medications during the timeframes detailed below.
* History of severe allergic reaction (per investigator judgment) or anaphylactic reaction to monoclonal antibody-based therapies or any components of OM336.
* Congenital immunodeficiency with recurrent severe infections over the last 12 months.
* Prior desensitization treatment within 6 months prior to inclusion:
1. Apheresis therapy (plasmapheresis or immunoadsorption)
2. CD20 mAb, e.g. rituximab or other
3. CD38 mAb, e.g. daratumumab or other
4. Proteasome inhibitor (bortezomib, carfilzomib)
5. Tocilizumab
6. Imlifidase
7. Any other investigational agent
* WOCBP: Pregnant, or breastfeeding, unwilling to practice adequate contraception.
* Pulmonary compromise requiring chronic supplemental oxygen use to maintain adequate oxygenation.
* Systemic herpes simplex (HSV) or symptomatic herpes zoster virus (HZV) (infection within 3 months prior to screening, or a history of disseminated or ophthalmic or central nervous system (CNS) infection with herpes zoster.
* Active or latent tuberculosis based on a positive QuantiFERON-TB Gold Plus test or equivalent test, medical history, examination, and chest X-ray.
* Active infection with hepatitis B (HBV), hepatitis C (HCV), or human immunodeficiency virus (HIV).
* Clinically significant infection (e.g., requiring hospitalization or parenteral antimicrobial therapy) within 3 months prior to screening.
* Any infection requiring oral antimicrobial therapy within 2 weeks prior to inclusion.
* A history of malignancy within the past 5 years (except for successfully treated basal or squamous cell carcinoma of the skin, or successfully treated carcinoma in situ of the cervix, with no evidence of recurrence). Note: low-grade prostate cancer (Gleason score of 6 or less, confined to the prostate and under surveillance/monitoring without need for imminent surgical intervention) is permitted, per judgment of the investigator.
* Live vaccine within 3 months prior to screening.
* Uncontrolled psychiatric conditions (eg, alcohol or drug abuse), dementia, or altered mental status precluding study enrollment according to the judgment of the investigators
* Inadequate liver function at Screening: Total bilirubin \>2 × the upper limit of normal (ULN) except if due to Gilbert syndrome; Alanine transaminase (ALT) and/or aspartate aminotransferase (AST) \>3 × ULN
* Currently enrolled in or participated in another clinical research study with investigational drug or device within 30 days or 5 drug half-lives of the investigational product (whichever is longer), prior to screening.
* Any clinically significant underlying illness that, in the opinion of the Investigator, may compromise study participation, present a safety risk to the participant, or may confound the interpretation of the study results, including general non-adherence to medication
* Known allergy to dexametasone and its excipients, diphenhydramine and its excipients, acetaminophen and its excipients or to valacyclovir and its excipients.
