Maintenance of complete remission after allogeneic stem cell transplantation in leukemia patients treated with Wilms tumor 1 peptide vaccine

Citation: Blood Cancer Journal (2013) 3, e130; doi:10.1038/bcj.2013.29

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LETTER TO THE EDITOR

Maintenance of complete remission after allogeneic stem cell transplantation in leukemia patients treated with Wilms tumor 1 peptide vaccine

Blood Cancer Journal (2013) 3, e130; doi:http://dx.doi.org/10.1038/bcj.2013.29

Web End =10.1038/bcj.2013.29 ; published online 2 August 2013

The prognosis of patients after allogeneic hematopoietic stem cell transplantation (HSCT) is still not satisfactory because, while treatment-related mortalities have decreased, relapse after HSCT remains a major concern. The effectiveness of allogeneic HSCT for hematological malignancies is the result of immunologic rejection of recipient leukemia cells by donor T cells, known as the graft-versus-leukemia (GVL) effect.1 It is thus obviously important to be able to exploit the GVL effect while minimizing graft-versus-host disease (GVHD). A targeted anti-leukemic immunotherapy, such as use of a leukemia vaccine,2 is a promising strategy to boost the GVL effect.

Wilms tumor 1 (WT1) protein is one of the best targets for leukemia vaccines. Overexpression of the wild-type WT1 gene has been detected in all types of human leukemia.35 We performed a phase I clinical study of immunotherapy targeting the WT1 protein in patients with leukemia, and were able to show that WT1 vaccination was safe and could induce WT1-specic cytotoxic T lymphocyte (CTL).6 Furthermore, reduction of minimal residual disease and long-lasting complete remission (CR) was observed in some leukemia patients who were given the WT1 vaccine.7

This report presents the results of phase I clinical study of WT1 vaccination for HLA-A*2402-positivie post-HSCT patients who were at high risk of relapse (HSCT in non-CR and 2nd HSCT for post-transplant relapse) or had already relapsed. The HLA-A*2402-restricted modied 9-mer WT1 peptide (amino acids 235243 CYTWNQMNL)8 was emulsied with Montanide ISA51 adjuvant. Patients were intradermally injected with 1.0 mg (three patients: UPNs 1, 4 and 6) or 3.0 mg (other six patients) of WT1 peptide four times weekly. When no adverse effects and no obvious disease progression were observed after the fourth injection, further WT1 vaccinations at 2-week intervals were administered.

Nine patients (ve with acute myeloid leukemia (AML), one each with acute lymphoblastic leukemia, chronic myelomonocytic leukemia, multiple myeloma and T-cell lymphoblastic lymphoma) were enrolled in this study (Supplementary Tables 1 and 2). Local inammatory response was observed at the vaccine injection sites of all patients. One patient (UPN5) suffered mild hypoxia (PaO2 65 mm Hg at room air) and restrictive pulmonary dysfunction (FEV1.0 40%) 65 days after the start of WT1 vaccination (day 199 after HSCT; Figure 1a). He was diagnosed with bronchioleitis obliterans (BO), which was a symptom of chronic GVHD. The patient recovered soon after administration of inhaled steroids. While early and sudden discontinuation of prednisolone and tacrolimus (day 103 after HSCT) were considered to be the reason for development of BO, the possibility of an association between BO and WT1 vaccination cannot be entirely ruled out. In other eight patients, no severe toxicities related to WT1 vaccine were observed (Table1).

Three AML patients (UPN13), who had undergone HSCT in non-CR, started WT1 vaccine in CR (Supplementary Tables 1 and 2). They started WT1 vaccination on post-HSCT days 141, 76 and 93

and have remained in CR for 1038, 973 and 662 days, respectively (as of 8 April 2013; Table1), suggesting the potential of WT1 vaccination as a maintenance therapy after HSCT.

Six patients started WT1 vaccination in non-CR and two of them became CR after WT1 vaccination. One B-ALL patient (UPN4) with MLL-AF4 underwent bone marrow transplantation from an HLA-matched unrelated donor during the rst CR. On post-HSCT day 111, MLL-AF4 and WT1 mRNA in peripheral blood (PB) had increased to 16 000 and 15 000 copies/mg RNA, indicating that the disease had relapsed. Tacrolimus and prednisolone doses were tapered off to induce GVL effects. The expression levels of MLL-AF4 and WT1 mRNA in PB had decreased to 2700 and 190

UPN5: AML(M5)

MCNU/ L-PAM/

TBI

uBMT

WT1 vaccine

mPSL/PSL

FK506

Inhaled steroid

1600

0 -50 0 50 100 150 200 250 300

Skin tumor

(Relapse)

1400

aGVHD

WT1 mRNA in PB

(copies/ gRNA)

1200

1000

%SpO2 91.8 97

800

Amy(U/L)128 220 300 74

BO

600

400 WT1

200

Days post transplant

UPN4: ALL (MLL/AF4+)

1

VP16/ CY/

TBI

uBMT WT1 vaccine

FK506

PSL

WT1CTL (% of MNCs)

MLL/AF4 (copies/ gRNA)

Blasts in BM (%)

0.02

0.01

0

104

1

WT1(copies/ gRNA)

aGVHD

102

106

103

4

0 -20 0 20 40 60 80 100 120 140 160 180 200

Days post transplant

Figure 1. Clinical course of patients who attained CR after the start of WT1 peptide vaccination. (a) Clinical course of UPN5 who achieved CR after administration of WT1 vaccine but stopped vaccination because of the development of bronchioleitis obliterans. (b) Clinical course of UPN4. Residual leukemia cells that were detected by MLL/AF4 expression disappeared after the start of WT1 vaccination. In both cases, rapid tapering of immune-suppressive drugs preceded WT1 peptide vaccination.

Letter to the Editor

2

Table 1. Patient outcomes

UPN Disease Status before vaccination

Adverse events

Number of vaccine doses

Outcome Additional therapy Survival

Post-HSCT

After start of vaccination

1 AML (M4) CR None 54 CR 1179 1038

2 AML(M4, DEK/CAN ) CR PLTk 52 CR 1049 973

3 AML CR None 38 CR 759 662

4 B-ALL (MLL/AF4 ) Molecular

relapse

None 71 CR 1312 1179

5 AML (M4) Relapse Amylasem, bronchileitis obliterans (cGVHD)a

2 CR 972 842 b

6 CMMoL Relapse None 25 PDc Chemo 2265 381

7 MM PD None 19 PD Chemo 1301 804

8 T-LBL Relapse None 4 PD Second transplant 955 656

9 AML (M2) Relapse None 17 PD Second transplant 1544 749

Abbreviations: ALL, acute lymphoblastic leukemia; AML, acute myeloid leukemia; CMMoL, chronic myelomonocytic leukemia; CR, complete remission; cGVHD, chronic graft-versus-host disease; HSCT, hematopoietic stem cell transplantation; MM, multiple myeloma; PD, progressive disease; T-LBL, T-cell lymphoblastic lymphoma. (8 April 2013). aA causal relationship between vaccination and this event was not strongly suspected, but could not be ruled out. bVaccination was discontinued. (The last injection was on post-HSCT day 60). cSize of the subcutaneous tumor decreased, but the disease relapsed in axial lymph nodes and stomach.

copies/mg RNA by day 132, and WT1 vaccination was started on day 133. MLL-AF4 mRNA had become undetectable by day 146, and had never appeared until post-HSCT day 1312 (day 1179 after the start of WT1 vaccination as of 8 April 2013; Figure 1b).

Skin tumors appeared in UPN5 (AML-M5) on post-HSCT day 103 and was diagnosed by biopsy as leukemia relapse. Tacrolimus was discontinued on day103, and WT1 vaccination was started on day 130. Cutaneous tumors had regressed 2 weeks after the start of WT1 vaccination, but vaccination was terminated after the second injection because of the development of BO as described earlier (Figure 1a). This patient has been remained in CR until post-HSCT day 972 (day 842 after the start of WT1 vaccination at 8 April 2013). While the exact contribution of the vaccination effect to the disease remission in addition to the GVL effect was unclear, the fact that both of these two patients still have remained in CR until now is encouraging to continue this trial. In the following phase II trials, the enumeration of WT1-specic CTLs should be performed more frequently after the start of vaccination to clarify the relationship between the effect of WT1 peptide vaccination and leukemia regression.

WT1 (a natural 9-mer WT1 peptide) HLA-A*2402 tetramer assays could be performed with peripheral blood mononuclear cell in seven of the nine patients to determine whether WT1235 peptide-specic CD8 T cells had increased after WT1 vaccination. The gates for WT1 tetramer cells were drawn as o0.1% of CD8

T cells were included in the tetramer-positive gate in multiple healthy individuals (Supplementary Figure 1A). WT1235 tetramer cells increased after the start of vaccination in three (UPNs1, 2 and 4) of the four patients who have remained in CR (Figure 1b and Supplementary Figure 1B). In the cases with progressive disease, continuous increase in the frequencies of WT1235 tetramer cells was not observed (Supplementary

Figure 1B).

Our results suggest that WT1 vaccination should be started when the leukemia burden is minimal. The timing of the start of WT1 vaccination may be also important. For the cases with good outcomes, WT1 vaccination was started 76140 days after transplantation (UPNs15), and at later times (days 2991815) for PD cases (UPNs 69). A lymphopenic environment a few months after transplantation may be favorable for rapid and extensive expansion of tumor antigen-specic CTLs.

In summary, this report suggests that WT1 vaccine can be safely administrated for post-HSCT patients with hematological malignancies and has potential as a maintenance therapy. Clinical benet of WT1 vaccination for post-HSCT patients will be evaluated in the subsequent phase II trials.

CONFLICT OF INTEREST

The authors declare no conict of interest.

T Maeda1, N Hosen2,3, K Fukushima1, A Tsuboi4, S Morimoto2, T Matsui1, H Sata1, J Fujita1, K Hasegawa2, S Nishida4, J Nakata5,

Y Nakae5, S Takashima5, H Nakajima6, F Fujiki6, N Tatsumi3, T Kondo7, M Hino8, Y Oji3, Y Oka5, Y Kanakura1, A Kumanogoh5 and H Sugiyama2

1Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Osaka, Japan;

2Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Osaka, Japan;

3Department of Cancer Stem Cell Biology, Osaka University Graduate School of Medicine, Osaka, Japan;

4Department of Cancer Immunotherapy, Osaka University Graduate School of Medicine, Osaka, Japan;

5Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Osaka University Graduate School of Medicine,

Osaka, Japan;

6Department of Cancer Immunology, Osaka University Graduate School of Medicine, Osaka, Japan;

7Department of Hematology and Oncology, Kyoto University Graduate School of Medicine, Kyoto, Japan and

8Department of Hematology and Oncology, Osaka City University Graduate School of Medicine, Osaka, Japan

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REFERENCES

1 Weiden PL, Flournoy N, Thomas ED, Prentice R, Fefer A, Buckner CD et al.

Antileukemic effect of graft-versus-host disease in human recipients of allogeneic-marrow grafts. N Engl J Med 1979; 300: 10681073.2 Rezvani K, Yong AS, Mielke S, Savani BN, Musse L, Superata J et al. Leukemia-associated antigen-specic T-cell responses following combined PR1

Blood Cancer Journal & 2013 Macmillan Publishers Limited

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and WT1 peptide vaccination in patients with myeloid malignancies. Blood 2008; 111: 236242.3 Cilloni D, Gottardi E, De Micheli D, Serra A, Volpe G, Messa F et al. Quantitative assessment of WT1 expression by real time quantitative PCR may be a useful tool for monitoring minimal residual disease in acute leukemia patients. Leukemia 2002; 16: 21152121.4 Miwa H, Beran M, Saunders GF. Expression of the Wilms tumor gene (WT1) in human leukemias. Leukemia 1992; 6: 405409.5 Inoue K, Sugiyama H, Ogawa H, Nakagawa M, Yamagami T, Miwa H et al. WT1 as a new prognostic factor and a new marker for the detection of minimal residual disease in acute leukemia. Blood 1994; 84: 30713079.6 Oka Y, Tsuboi A, Taguchi T, Osaki T, Kyo T, Nakajima H et al. Induction of WT1 (Wilms tumor gene)-specic cytotoxic T lymphocytes by WT1 peptide

vaccine and the resultant cancer regression. Proc Natl Acad Sci USA 2004; 101: 1388513890.7 Tsuboi A, Oka Y, Kyo T, Katayama Y, Elisseeva OA, Kawakami M et al. Long-term WT1 peptide vaccination for patients with acute myeloid leukemia with minimal residual disease. Leukemia 2012; 26: 14101413.8 Tsuboi A, Oka Y, Udaka K, Murakami M, Masuda T, Nakano A et al. Enhanced induction of human WT1-specic cytotoxic T lymphocytes with a 9-mer WT1 peptide modied at HLA-A*2402-binding residues. Cancer Immunol Immunother 2002; 51: 614620.

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