Rituximab Therapy Is Effective for Posttransplant
Lymphoproliferative Disorders after Solid Organ
Results of a Phase II Trial
Anne H. Blaes, M.D.1
Bruce A. Peterson, M.D.2
Nancy Bartlett, M.D.3
David L. Dunn, M.D., PhD.4
Vicki A. Morrison, M.D.2,5
1Department of Medicine, The University of Min-
nesota, Minneapolis, Minnesota.
2Department of Hematology, Oncology, and
Transplantation, The University of Minnesota, Min-
3Department of Oncology, Washington University
School of Medicine, St. Louis, Missouri.
4Department of Surgery, The University of Minne-
sota, Minneapolis, Minnesota.
5Veterans Affairs Medical Center, Minneapolis,
Address for reprints: Anne H. Blaes, M.D., Depart-
ment of Medicine, The University of Minnesota,
14-100 Phillips Wangensteen Building, MMC 284,
420 Delaware Street S.E., Minneapolis, MN 55455;
Fax: (612) 625-3238; E-mail: firstname.lastname@example.org
Received February 28, 2005; revision received
May 24, 2005; accepted May 31, 2005.
uncommon complication of solid organ transplantation with a high mortality rate
reported after conventional therapies. Alternative treatments such as rituximab
have been explored.
Eleven patients with PTLD, who were CD20 positive, received an
intravenous dose of rituximab, 375 mg/m2, weekly ? 4 weeks, repeated every 6
months for 2 years in responding patients. The median age of the patients was 56
years (range, 43–68 yrs), and 9 patients were male. The type of solid organ
transplantation that these patients received included lung (five patients), kidney
(four patients), heart (one patient), and kidney/pancreas (one patient). The median
time from transplantation to a PTLD diagnosis was 9 months (range, 1–122 mos).
Diagnostic B-cell histology was diffuse large cell lymphoma or polymorphous
process. No patient had bone marrow or central nervous system involvement.
Primary extranodal disease was noted in 82% of patients. Immunosuppressive
therapy was decreased at the time of diagnosis.
Rituximab was well tolerated, with mild infusional blood pressure
alterations noted in two patients. The median follow-up period was 10 months
(range, 1–32 mos). The overall response rate was 64%, with 6 complete responses
(CR), 1 partial response, 2 cases of progressive disease, and 2 deaths. The median
duration of CR was 8 months (range, 2–19? mos). The median time to treatment
failure was 10 months (range, 5–25? mos). The median survival was 14 months
(range, ? 1–32? mos). Four patients were alive at the time of last follow-up.
CONCLUSIONS. Single-agent rituximab may offer a response and survival advan-
tage in patients with PTLD. Further evaluation of rituximab in these disorders,
potentially in combination with other therapies, is warranted. Cancer 2005;104:
1661–7. © 2005 American Cancer Society.
Posttransplant lymphoproliferative disorders (PTLD) remain an
KEYWORDS: posttransplant lymphoproliferative disorders, rituximab, solid organ
transplantation, extranodal disease.
reported incidence varies from 1% to 20%,1–3depending on factors
such as type of immunosuppression, type of organ transplanted, and
immune status for Epstein–Barr virus (EBV) infection.4–6PTLD may
be of variable histology, not always fitting International Working
Formulation criteria. Most patients develop B-cell (CD20 positive)
malignancies, either monoclonal or polyclonal. These malignancies
tend to behave more aggressively, and in general, to have poorer
osttransplant lymphoproliferative disorders (PTLD) are a serious
complication arising in solid organ transplant recipients. The
© 2005 American Cancer Society
Published online 7 September 2005 in Wiley InterScience (www.interscience.wiley.com).
outcomes than lymphomas occurring in nonimmuno-
compromised patients.7Despite the use of a variety of
therapies, including a reduction in immunosuppres-
sive therapy, surgical resection, chemotherapy, and
radiation therapy,8–11mortality rates remain high. As a
result of the poor response to conventional therapies
in these patients, alternative treatment options such
as therapy with monoclonal antibodies (MoAbs) have
Immunotherapy with MoAbs (anti-CD20, anti-
CD21, and anti-CD22) has demonstrated some effi-
cacy, offering a potentially safe and effective treat-
ment.5,12,13Rituximab, a MoAb targeted against CD20,
was first approved in 1997 for the treatment of B-cell
non-Hodgkin lymphoma (NHL). Although rituximab
is widely used in the treatment of NHL, reports con-
cerning the safety and efficacy of rituximab in solid
organ transplant recipients with PTLD are to our
knowledge limited.14–21We report our experience with
rituximab as therapy in a series of patients with PTLD
after solid organ transplantation.
MATERIALS AND METHODS
Between January 1999 and July 2001, 11 patients with
newly diagnosed PTLD were identified and evaluated
at the University of Minnesota, Washington University
School of Medicine (St. Louis, MO), and the Veterans
Affairs Medical Center (Minneapolis, MN). All patients
had previously undergone solid organ transplantation
at one of these sites.
Each of these patients was enrolled on a protocol
designed to evaluate the efficacy of rituximab in pa-
tients with PTLD. Inclusion criteria included a histo-
logic diagnosis of PTLD of a B-cell immunophenotype
(CD20 positive), with histopathologic features consis-
tent with malignant lymphoma, and measurable dis-
ease. Patients were age ? 18 years, with an expected
survival of ? 3 months, and a Cancer and Leukemia
Group B performance status of 0, 1, or 2. Adequate
bone marrow, renal, and hepatic function was re-
quired for study entry. Patients with human immuno-
deficiency virus infection, uncontrolled infection, lym-
phomatous meningitis, or women who were pregnant
were not eligible. Patients may have received previous
chemotherapy, but no chemotherapy was permitted
in the 4 weeks prior to study entry, and no previous
All patients were staged using computed tomog-
raphy (CT) scans of the chest, abdomen, and pelvis.
Central nervous system (CNS) involvement was eval-
uated by lumbar puncture or a head CT scan. All
patients received a bone marrow biopsy.
The primary study endpoints were disease re-
sponse, duration of disease remission, time to treat-
ment failure, and survival. Secondary endpoints were
safety, hematologic toxicity, and infectious complica-
After signed informed consent was obtained from
all patients, rituximab (Genentech, Inc., South San
Francisco, CA) was administered as a continuous in-
travenous (i.v.) infusion over 1–4 hours at an initial
dose of 375 mg/m2on Days 1, 8, 15, and 22. In patients
with responsive disease, this 4-week cycle of therapy
was repeated every 6 months for a maximum of 4
cycles of therapy over 2 years. The pretreatment reg-
imen was comprised of acetaminophen at a dose of
650 mg orally, diphenhydramine at a dose of 50 mg
orally or i.v. 30 minutes before rituximab infusion, and
antiemetics as needed. Patients were reassessed at
3-month intervals with laboratory evaluations and CT
scans. No patient was lost to follow-up.
Chronic immunosuppressive therapy for the solid
organ transplantation patients included combinations
of prednisone, azathioprine, cyclosporine, mycophe-
nolate, and tacrolimus, which varied by institution
and care provider. No patient received OKT3. At the
time of PTLD diagnosis, immunosuppressive therapy
was reduced in dose or discontinued in all patients at
the discretion of the primary managing physician. The
concomitant use of acyclovir was also left to the dis-
cretion of the primary managing physician.22
A complete response (CR) was defined as no evi-
dence of disease by standard laboratory, radiographic,
or histopathologic parameters, which persisted for ? 4
weeks. A partial response (PR) was defined as a ? 50%
decrease in the sum of the products of the perpendic-
ular dimensions of all measurable disease sites, with-
out the appearance of new lesions. Stable disease or
no response was defined as a ? 50% decrease in the
sum of the products of the perpendicular dimensions
of all measurable disease sites, and lasting for ? 8
weeks. Progressive disease (PD) was defined as a
? 25% increase in any lesion, the reappearance of
measurable disease, a clear worsening of evaluable
disease, or the appearance of any new lesions. Disease
remission duration was the interval from the time of
documentation of a response to the first evidence of
disease recurrence or disease progression. Time to
failure was the interval from the initiation of therapy
to either progressive disease, disease recurrence, or
death from any cause. Survival was defined as the time
from PTLD diagnosis to death. Patients who went off
study for disease progression or to receive other ther-
apy were considered as treatment failures. All subjects
who received at least one dose of medication were
assessed for clinical safety, tolerability, and efficacy.
The planned target sample size for the current
study was 14 patients. However, the study was closed
1662CANCER October 15, 2005 / Volume 104 / Number 8
after the accrual of 11 patients due to the relative
success of the treatment regimen in this patient pop-
ulation, and the desire to build on these findings in a
subsequent treatment trial. The planned statistical
analysis was descriptive only.
The 11 patients enrolled in the current study were
diagnosed with PTLD at a median of 9 months after
solid organ transplantation (range, 1–122 mos). The
patient and transplant characteristics are summarized
in Tables 1 and 2. There were four kidney transplant
patients, one heart transplant patient, one kidney-
pancreas transplant patient, four single-lung trans-
plant patients, and one bilateral lung transplant pa-
tient. The median age of the patients was 56 years
(range, 43–69 yrs).
At the time of diagnosis, two patients had disease
in the transplanted organ. Disease was classified as
Ann Arbor Stage I in two patients, Stage II in three
patients, Stage III in three patients, and Stage IV in
three patients. No patient had CNS or bone marrow
involvement. Extranodal disease was found in 9 of 11
patients (82%) in the following sites: lung, stomach,
small bowel, skin, liver, and spleen. Creatinine levels
ranged from 1.0 to 2.6 mg/dL. Hemoglobin levels
ranged from 8.3 to14.4 g/dL. The median lactate de-
hydrogenase (LDH) level was 518 IU/L (range, 189–
1644 IU/L) (normal LDH values, 325–750 IU/L). Titers
for EBV or stains by in situ hybridization were positive
in six patients, negative in one patient, and not per-
formed in four patients. Three patients received a brief
course of acyclovir. Immunosuppressive therapy was
reduced in dose or discontinued in all patients at the
discretion of the primary managing physician. None
of the patients achieved a decrease in tumor size at the
time immunosuppression was decreased or discontin-
ued or acyclovir was used. Ten of the 11 patients
received rituximab as primary therapy for PTLD. One
patient with small bowel involvement underwent je-
junal resection and received two cycles of chemother-
apy with cyclophosphamide, doxorubicin, vincristine,
and prednisone (CHOP) before the initiation of ritux-
Response and outcome data are summarized in
Table 3. The median follow-up period was 10 months
(range, 1–32 mos). The overall response rate was 64%
(55% CR and 9% PR), with 6 CR, 1 PR, 2 cases of PD,
and 2 deaths. The 2 deaths occurred in patients who
died of disease progression within 1–3 weeks after the
intiation of rituximab. Three patients went on to re-
ceive other therapies after initial treatment with ritux-
imab. Patient 2, who developed disease progression
while receiving initial rituximab, achieved a CR to
CHOP chemotherapy (5 cycles), and was disease free
at time of death from massive hemorrhage 18 months
after diagnosis.10,23Patient 8, who achieved only a
brief (3 mos) PR to initial rituximab therapy, subse-
quently received an infusional regimen of 4 cycles of
cyclophosphamide, doxorubicin, vincristine, pred-
nisone, and etoposide (CHOPE), and remained in a
stable PR at the time of last follow-up, 17 months
after diagnosis.24Patient 9, who had a small bowel
perforation after 3 doses of rituximab, went on to
receive 4 cycles of infusional CHOPE, achieving a
PR, and was alive at the time of last follow-up, 15
months after diagnosis. Of the six patients who
achieved a CR with rituximab, two occurred after
one cycle of rituximab and four occurred after two
cycles of rituximab. No patient developed a disease
recurrence during the follow-up period. The median
duration of a CR was 8 months (range, 2–25? mos).
The time to treatment failure was found to range
from 5 to 25? months (median, 10 mos). The me-
dian survival of the patients was 14 months (range,
? 1–32? mos) (Fig. 1). Four patients remained alive
at the time of last follow-up.
Rituximab was generally well tolerated with mild
blood pressure changes noted in two patients. One
patient had brief infusion-related hypotension that
resolved with fluid administration, and the other pa-
tient developed mild hypertension during infusion
that was controlled with medication.
It has been observed that the risk of malignancies in
recipients of solid organ transplants is up to 100 times
that of the general population when matched by
Age at PTLD
PTLD diagnosis in
F: female; M: male; PTLD: posttransplant lymphoproliferative disorders; F: female; M: male.
Treatment of PTLD with Rituximab/Blaes et al. 1663
age.8,25–28The most common malignancies found are
skin or lip carcinomas followed by lymphoprolifera-
tive disorders. A number of hypotheses have been
proposed to explain this trend in an excess of lympho-
proliferative disorders: antigenic stimulation from the
allograft, chronic immunosuppression, an oncogenic
effect of immunosuppression, as well as an associa-
tion with EBV infection.29The lymphoproliferative
disorders have been found to have a different histol-
ogy, to be more clinically aggressive, and, in general,
to result in poorer outcomes than “de novo” lympho-
mas.7The overall mortality, despite treatment, of
PTLD has reportedly varied from 60–81%, with a me-
dian survival of 14–19 months.7,30
Historically, there have been a number of thera-
FIGURE1. Overall survival of patients with posttransplant lymphoproliferative
disease who were treated with rituximab.
Outcome and Response Data
Response to rituximab
duration in mos
in mosCause of deathb
Alive in CR
Alive in CR
Alive in PR after CHOPE
Alive in PR after CHOPE
PR: partial disease remission; CR: ? complete disease remission; PD ? progressive disease; D ? death; ARDS: acute respiratory distress syndrome; CHOPE: cyclophosphamide, doxorubicin, vincristine, prednisone,
and etoposide; RSV: respiratory syncytial virus.
aResponse after first cycle of rituximab.
bPatients were in complete disease remission at the time of death unless otherwise specified.
Patient no.Prednisone Azathioprine
therapy CyclosporineMMF TacrolimusHistology Stage
MMF: mitoxantrone, methotrexate, and 5-fluorouracil; E: extranodal; DLCL: diffuse large cell lymphoma;NHL: non-Hodgkin lymphoma.
1664CANCER October 15, 2005 / Volume 104 / Number 8
peutic approaches to PTLD. A reduction in immuno-
suppression has been shown to be helpful in select
patients.1,3,8,30Surgical resection and radiotherapy
have been implemented and shown to be effective
primarily in patients with limited-stage disease.1,3,9In
the 1980s, acyclovir therapy was evaluated and shown
to have some benefit in individuals with EBV infec-
tion.22,23,29Combination chemotherapy regimens in-
cluding CHOP, COMP (cyclophosphamide, vincris-
arabinoside), and proMACE-cytaBOM (cyclophospha-
mide, doxorubicin, etoposide, cytosine arabinoside,
nisone), and CHOPE have all been used with anec-
dotal success.1,3,10,24,31–33As a result of the limited
efficacy noted with chemotherapy as well as the in-
creased morbidity associated with treatment,31–35al-
ternative therapies have been investigated.
Rituximab is a genetically engineered chimeric
murine/human MoAb directed at the CD20 antigen
found on normal and malignant B lymphocytes. It
initially was approved in 1997 for the treatment of
recurrent or refractory low-grade or follicular, CD20-
positive, B-cell NHL. B-cell MoAbs such as rituximab
have demonstrated increased response rates and a
decrease in morbidity in these patients when com-
pared with conventional therapies.5,13
As a result of the success of rituximab in low-
grade NHL, this agent has been utilized in the ther-
apy of small samples of transplant patients with
PTLD. Several case reports have been described in
which recipients of liver, heart, intestinal, kidney,
and lung transplants have achieved a CR with sin-
gle-agent rituximab (Table 4).14–21Additional small
case series have been reported. In a series reported
by Ganne et al.,17in which eight solid organ trans-
plant recipients with PTLD were treated with ritux-
imab therapy, seven of these eight patients achieved
a CR, with one patient requiring two courses of
therapy to achieve this response. All 8 patients re-
mained alive at a mean follow-up period of 22.5
months, with 3 patients reported to be in disease
remission for ? 2.5 years. Preliminary reports of
several larger series of patients with PTLD who were
treated with rituximab have been reported in ab-
stract form.36–40The response rates have varied
from 37–69% (median, 64%) with a follow-up of
8–32 months. Few side effects of rituximab therapy
were reported from these case reports and series.
Preliminary results of the use of rituximab in
combination with chemotherapy such as CHOP (R-
CHOP) also have been reported in the literature.
Shammo et al.34reported that of 7 patients with
PTLD who were treated with chemotherapy (R-
CHOP in 6 patients and CHOP in 1 patient), 6
achieved a CR and remained disease free at 18–60
months. In a second report, four patients received
R-CHOP and three received single-agent rituximab.
The mean overall survival in this group was 18
months, compared with 14 months in the 11 pa-
tients who received CHOP chemotherapy.35
In the current study, as well as in preliminary
reports of other series, rituximab therapy appears to
be a promising treatment for PTLD. We treated 11
patients with PTLD with rituximab, with a 64% over-
all response rate and a 55% CR rate reported. The
median survival period was 14.5 months. Rituximab
was well tolerated with few side effects in this very
sick population. Based on these data, rituximab ap-
pears to be beneficial as first-line therapy for PTLD.
Because it has been shown that rituximab adds to
the efficacy of chemotherapy in de novo diffuse
lymphoma, further studies to investigate the use of
chemotherapy in conjunction with rituximab in pa-
tients with PTLD are warranted.
Case Reports of Single-Agent Rituximab Therapy in PTLDa
StudyNo. of patients Type of organ transplantedCR response CR duration
Yedibela et al.14
Verschuuren et al.15
Oertel et al.16
Ganne et al.17
6 Kidney, 1 kidney/pancreas, 1 liver
2, 6, 16 mos
In 3 patients, ? 2.5 yrs
In 4 patients, ? 10 mos
? 10 mos
Median 8 mos (range 3–30)
6, 8 mos
Pham et al.18
Berney et al.19
Cook et al.20
Zilz et al.21
PTLD: posttransplant lymphoproliferative disorders; CR: complete disease remission; mos: months; yrs: years.
aAll patients received rituximab 375 mg/m2weekly for 4 weeks.
Treatment of PTLD with Rituximab/Blaes et al. 1665
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Treatment of PTLD with Rituximab/Blaes et al.1667