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Post-transplant Lymphoproliferative DisorderPhase 1/2PLUTONCT07573436

Loncastuximab Tesirine and Rituximab as First-line Therapy in Patients With Post-transplant Lymphoproliferative Disorder (PLUTO)

A Phase 1/2 study testing Loncastuximab tesirine and Rituximab or rituximab biosimilar in people with Post-transplant Lymphoproliferative Disorder, run by University of Utah at 1 site in United States.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

The purpose of phase I of this clinical trial is to learn the recommended dose of the drugs loncastuximab tesirine and rituximab in participants with post-transplant lymphoproliferative disorders (PTLD). Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Loncastuximab tesirine and Rituximab or rituximab biosimilar
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
23 participants
Where
1 siteUnited States
Study dates
Nov 2026to Jun 2031
Phase
Phase 1/2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Subject aged ≥ 18 years.
  • Histologically confirmed B-cell PTLD (monomorphic and polymorphic) following solid organ transplantation; with or without EBV association.
  • --Note: Subjects with classic Hodgkin-like PTLD are excluded.
  • Measurable disease as defined by the 2014 Lugano Classification as assessed by positron-emission tomography (PET)- computed tomography (CT) or by CT or magnetic resonance imaging (MRI) if the tumor is not fluorodeoxyglucose (FDG)-avid on screening
  • ECOG Performance Status ≤ 2.
  • Adequate organ function as defined as:
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  • Hematologic:
  • Absolute neutrophil count (ANC) ≥ 1000/mm3
  • Platelet count ≥ 75,000/mm3
  • Hemoglobin ≥ 8 g/dL
  • Hepatic:
  • Bilirubin ≤1.5 x upper limit of normal (ULN) or ≤3 x ULN with document liver involvement and/ or Gilbert's disease
  • Transaminases (AST or ALT) ≤ 3 x ULN or ≤ 5 x ULN with documented liver involvement
  • Renal:
  • Estimated creatinine clearance ≥ 60 mL/min by Cockcroft-Gault formula.
  • For female subjects: Negative pregnancy test or evidence of post-menopausal status. The post-menopausal status will be defined as having been amenorrheic for 12 months without an alternative medical cause or having undergone surgical sterilization (bilateral oophorectomy or hysterectomy). The following age-specific requirements apply:
  • Women < 50 years of age:
  • Amenorrheic for ≥ 12 months following cessation of exogenous hormonal treatments; and
  • Luteinizing hormone and follicle-stimulating hormone levels in the post-menopausal range for the institution; or
  • Underwent surgical sterilization (bilateral oophorectomy or hysterectomy).
  • Women ≥ 50 years of age:
  • Amenorrheic for 12 months or more following cessation of all exogenous hormonal treatments; or
  • Had radiation-induced menopause with last menses >1 year ago; or
  • Had chemotherapy-induced menopause with last menses >1 year ago; or
  • Underwent surgical sterilization (bilateral oophorectomy, bilateral salpingectomy, or hysterectomy).
  • Female subjects of childbearing potential and male subjects with a sexual partner of childbearing potential must agree to use a highly effective method of contraception and the lactation requirements as described in Sections 5.4.1 and 5.4.2.
  • Subjects or their legal representatives must be able to read, understand, and provide informed consent to participate in the trial.
  • Willing and capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol

Who cannot join

  • PTLD following liquid transplantation
  • CNS involvement
  • Prior treatment for PTLD with the exception of radiation, antivirals, steroids and reduced immunosuppression
  • Human immunodeficiency virus (HIV) infection
  • Major surgery within 4 weeks prior to enrolment
  • History of bleeding diathesis (e.g., von Willebrand's disease), hemophilia, or active bleeding.
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  • Subjects with chronic liver disease with hepatic impairment Child-Pugh class C
  • Pregnant or lactating or intending to become pregnant during the study
  • Active autoimmune disease which, in the opinion of the investigator, may negatively impact subject safety or interfere with study participation.
  • The diagnosis of another malignancy which, in the opinion of the investigator, is likely to negatively impact subject safety or interfere with study participation.
  • Significant medical diseases or conditions including those requiring substantial changes in concomitant medications, as assessed by the investigator, that would substantially increase the risk-to-benefit ratio of participating in the study. This includes, but is not limited to the following conditions:
  • Cardiovascular disorders:
  • Congestive heart failure New York Heart Association Class III or IV, unstable angina pectoris, serious cardiac arrhythmias.
  • Myocardial infarction (MI) within 6 months before the first dose.
  • QTc prolongation defined as a QTcF > 480 ms.
  • Congenital long QT syndrome or a corrected QT measure (QTc) interval of >480 ms at screening (unless secondary to pacemaker or bundle branch block).
  • Grade 2 or higher edema (peripheral, pleural or ascites)
  • Grade 1 or higher pericardial effusion
  • Severe pulmonary disease
  • Uncontrolled diabetes mellitus
  • Severely immunocompromised state
  • Any other condition that would, in the Investigator's judgment, contraindicate the subject's participation in the clinical study due to safety concerns or compliance with clinical study procedures.
  • Active systemic bacterial, viral, fungal, or other infection requiring systemic treatment at time of screening
  • Subjects with evidence of active hepatitis B infection, based on positive surface antigen or Hepatitis B DNA PCR are excluded. Subjects who are Hepatitis B core antibody positive must take prophylaxis with entecavir or equivalent and be willing to undergo monthly Hepatitis B DNA PCR testing
  • Active hepatitis C infection
  • Grade 2 or higher rash
  • Clinically significant fluid accumulation in the third space
  • Subjects taking prohibited medications as described in Section 6.8.1. A washout period of prohibited medications for a period of at least five half-lives or as clinically indicated should occur before the start of treatment.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Narendranath Epperla, MD contact

801-585-0255

naren.epperla@hci.utah.edu

United States1 site
  • Huntsman Cancer Institute at University of Utah

    Salt Lake City, Utah, 84112

    Rachel Kingsford, 801-585-0115, rachel.kingsford@hci.utah.edu

Other trials in United States

About this study

Official title: A Phase 1/2 Study of Loncastuximab Tesirine and Rituximab as First-line Therapy in Patients With Post-transplant Lymphoproliferative Disorder (PLUTO)

The purpose of phase I of this clinical trial is to learn the recommended dose of the drugs loncastuximab tesirine and rituximab in participants with post-transplant lymphoproliferative disorders (PTLD).

The purpose of phase II of this clinical trial is to learn if the drugs loncastuximab tesirine and rituximab are effective in participants with post-transplant lymphoproliferative disorders (PTLD).

Being tested
Loncastuximab tesirine, Rituximab or rituximab biosimilar

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Loncastuximab tesirineDrug

    Lonca will be administered by IV at 75µg/kg every 3 weeks (DL1).

  • Rituximab or rituximab biosimilarDrug

    Also called RITUXAN, Truxima, Ruxience, Riabni

    Rituximab or rituximab biosimilar will be administered by IV at 375 mg/m2 on Day 1 of every cycle. Lonca will be administered first, followed by rituximab (with a 30 min wait time between the two agents)

Study groups in NCT07573436
Study groupRoleWhat they receive
Dose Level 1 (starting dose): SD or PDExperimentalDose Level 1: * Loncastuximab tesirine: 0.075 mg/kg IV every 3 weeks * Rituximab: 375 mg/m2 IV This arm included participants who had SD (Stable Disease) or PD (Progressive Disease) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they do not achieve a response, they will come off the study but will be monitored for survival.
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar
Dose Level 1 (starting dose): PRExperimentalDose Level 1: * Loncastuximab tesirine: 0.075 mg/kg IV every 3 weeks * Rituximab: 375 mg/m2 IV This arm included participants who had a Partial Response (PR) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they achieve PR, they will have the option to receive either rituximab consolidation or R-CHOP (at the physician's discretion).
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar
Dose Level 1 (starting dose): CRExperimentalDose Level 1: * Loncastuximab tesirine: 0.075 mg/kg IV every 3 weeks * Rituximab: 375 mg/m2 IV This arm included participants who had a Complete Response (CR) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they achieve a CR after 4 cycles of Lonca-R, they will receive rituximab consolidation (SOC).
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar
Dose Level 2: SD or PDExperimentalDose Level 2: * Loncastuximab tesirine: 0.15 mg/kg IV every 3 weeks for the first 2 cycles, then 0.075 mg/kg starting C3 * Rituximab: 375 mg/m2 IV This arm included participants who had SD (Stable Disease) or PD (Progressive Disease) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they do not achieve a response, they will come off the study but will be monitored for survival.
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar
Dose Level 2: PRExperimentalDose Level 2: * Loncastuximab tesirine: 0.15 mg/kg IV every 3 weeks for the first 2 cycles, then 0.075 mg/kg starting C3 * Rituximab: 375 mg/m2 IV This arm included participants who had a Partial Response (PR) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they achieve PR, they will have the option to receive either rituximab consolidation or R-CHOP (at the physician's discretion).
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar
Dose Level 2: CRExperimentalDose Level 2: * Loncastuximab tesirine: 0.15 mg/kg IV every 3 weeks for the first 2 cycles, then 0.075 mg/kg starting C3 * Rituximab: 375 mg/m2 IV This arm included participants who had a Complete Response (CR) after the first 6 weeks of treatment. Lonca-R will be administered for 4 cycles with response assessment at 6 weeks (+/- 1 week) following the last Lonca-R treatment. If they achieve a CR after 4 cycles of Lonca-R, they will receive rituximab consolidation (SOC).
Receives: Drug: Loncastuximab tesirine; Drug: Rituximab or rituximab biosimilar

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Phase I: Define Maximum Tolerated Dose (MTD) based on the rate of dose-limiting toxicities (DLTs) during the DLT evaluation period.

    To assess the Recommended Phase 2 Dose (RP2D) of loncastuximab tesirine and rituximab in participants with post-transplant lymphoproliferative disorders (PTLD).

    Measured: 4 years

  2. Phase II: The complete response (CR) rate after 4 cycles of lonca-R per Lugano 2014 criteria1.

    To assess the efficacy of the combination of lonca-R based on CR rate after 4 cycles.

    Measured: 4 years

Secondary outcomes (5)
  1. The frequency of adverse events (AEs) and serious adverse events (SAEs) characterized by type, severity (as defined by the NIH CTCAE, version 6.0), seriousness, duration, and relationship to study treatment.

    To assess the safety and tolerability of lonca-R in subjects with B-cell PTLD.

    Measured: 4 years

  2. The overall response rate (ORR) after 4 cycles of lonca-R.

    To determine ORR after 4 cycles of lonca-R in subjects with B-cell PTLD.

    Measured: 4 years

  3. The best complete response (CR) rate is defined as CR at the completion of 4 cycles of lonca-R or 4 cycles of lonca-R and 4 cycles of consolidation of rituximab monotherapy (every 3 weeks) in subjects with B-cell PTLD.

    To determine the best CR rate in subjects with B-cell PTLD.

    Measured: 4 years

  4. Median and two year progression-free survival (PFS). PFS will be as defined as the time from study drug initiation to the time of documented disease progression (as assessed by Lugano Criteria), or death from any cause.

    To assess PFS.

    Measured: 4 years

  5. Median and two year overall survival (OS). OS is defined as the time from initiation of treatment until death from any cause.

    To assess OS.

    Measured: 4 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 May 2026
  2. Study startNov 2026 (estimated)
  3. Primary completionJun 2030 (estimated)
  4. Study completionJun 2031 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1/2
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
23 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07573436
Sponsor's protocol ID
HCI198713
Acronym
PLUTO
Status last verified
Oct 2026
First submitted
30 Apr 2026
Last updated
9 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 1/2 study testing Loncastuximab tesirine and Rituximab or rituximab biosimilar in people with Post-transplant Lymphoproliferative Disorder, run by University of Utah at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 28 inclusion and 28 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 9 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Rachel Kingsford (801-585-0115, rachel.kingsford@hci.utah.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Phase I: Define Maximum Tolerated Dose (MTD) based on the rate of dose-limiting toxicities (DLTs) during the DLT evaluation period. (time frame: 4 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Oct 2026.

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