Safety and feasibility of umbilical cord mesenchymal stem cells in treatment-refractory systemic lupus erythematosus nephritis: time for a double-blind placebo-controlled trial to determine efficacy
Arthritis Research & Therapy
Safety and feasibility of umbilical cord mesenchymal stem cells in treatment-refractory systemic lupus erythematosus nephritis: time for a double-blind placebo-controlled trial to deter- mine efficacy
Thasia G Woodworth 0
Daniel E Furst 0
0 Division of Rheumatology, David Geffen School of Medicine, University of California , Los Angeles, CA , USA
As translational clinical researchers familiar with the risk-benefit of hematopoietic stem cell transplantation in autoimmune diseases, we are intrigued by the recent report of umbilical cord mesenchymal stem cell (UC-MSC) transplantation in treatment-refractory systemic lupus erythematosus nephritis by Wang and colleagues. They report the results of an open-label single-arm multicenter phase I/II study. This stimulated us to examine whether collective data from this group provide sufficient evidence for the feasibility, safety, dose rationale, and potential efficacy of UC-MSCs to conduct a randomized controlled trial in such patients. Results, though confounded by variable baseline prednisone and immuno-suppressive treatment, appear to indicate nearterm response rates of approximately 50%, which are comparable to those seen with hematopoietic stem cell transplantation but with less morbidity and mortality.
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Protocol NCT01741857, first posted on 26 November
2012 and updated 1 November 2013, appears to be the
protocol for the study recently published in Arthritis
Research & Therapy [
1
]. The report largely reflects the
protocol, although dose is not described and patient
entry criteria required a dose of prednisone of more than
20 mg/day. In the report, only 10 of 40 patients were
receiving prednisone of more than 20 mg/day, and one
dose - 1 × 106 cells per kg, infused twice 7 days apart
was evaluated. The umbilical cord mesenchymal stem
cells (UC-MSCs) for infusion were centrally prepared by
using a well-standardized, quality-controlled method,
and infusions were well tolerated. One-year mortality
(two patients with uncontrolled SLE) and morbidity (five
serious infections) compare favorably to those seen with
hematopoietic stem cell transplantation in patients with
SLE [
6
].
Previously reported studies by this group [
2-5
]
evaluated stem cells derived from either bone marrow
of healthy relatives or umbilical cords donated by
healthy consenting mothers in patients with
treatmentrefractory SLE. Most patients had active SLE nephritis
despite receiving prednisone of more than 20 mg and
immuno-suppression with cyclophosphamide,
mycophenylate mofetil, or leflunomide or a combination of these.
In addition, they usually received ‘conditioning’ by
cyclophosphamide 0.8 to 1.8 mg/kg per day for 3 days prior
to transplant. In contrast, in the recently reported study
[
1
], only UC-MSCs were transplanted, without
‘conditioning’, in patients with active treatment-refractory SLE
nephritis receiving a more variable background of
prednisone, often less than 20 mg/day, and immunosuppression.
aPharmacodynamic (PD) markers = increased peripheral blood regulatory T (Treg) cells, balanced T helper 1 (Th1)/Th2 cytokines; b[
2
] baseline (BL) proteinuria 3.1
(±1.2) g/day versus 3 months, 1.3 (±0.9) g/day (P <0.001, n = 15); [
3
] BL proteinuria 2.7 (±1.2) g/day versus 6 months, 0.9 (±0.8) g/day (P <0.01, n = 12); cprotocol
described at ClinicalTrials.gov consistent with this study, but not explicitly noted in report. BM, bone marrow; CR, complete remission; CYC, cyclophosphamide;
MCR, major clinical response; MSC, mesenchymal stem cell; ND, not done; NR, not reported; PCR, partial clinical response; SLEDAI, Systemic Lupus Erythematosus
Disease Activity Index; SLEN, systemic lupus erythematosus nephritis; UC, umbilical cord.
Although efficacy is difficult to evaluate because major
clinical response (MCR) required that prednisone be
tapered to less than 10 mg/day, while maintaining
improvements in disease activity measured by British Isles Lupus
Assessment Group and Systemic Lupus Erythematosus
Disease Activity Index, conditioning is apparently not
needed. However, because 18 of 40 patients were receiving
prednisone of less than 20 mg/day at the start of the study,
the efficacy criterion of ‘tapered’ prednisone is difficult to
assess. Although 24 responses - 13 MCR and 11 partial
clinical response (CR) - are reported, 6 MCR and 6 partial
CR cannot be verified in the reported data, because
prednisone tapering appears not to meet criteria for response.
In addition, relapse occurred within a year in 6 patients,
most receiving at least 20 mg prednisone at baseline.
Nevertheless, there may be some evidence for potential
efficacy or perhaps corticosteroid sparing, but dose regimen
results are not sufficiently clear, or defined by relevant
pharmacodynamic activity, to identify a specific UC-MSC
dose to use for a randomized controlled trial (RCT).
Review of previous reports may provide some
additional insight (Table 1). One open-label study in (...truncated)