Thus, a recent animal study suggested that a possible alternative strategy might be to administer Hematide to patients with PRCA due to anti-rhEPO antibodies, which should enable ongoing stimulation of erythropoiesis. Future prospects: proposal for a ﬁrst-line therapy in primary acquired PRCA There are several options for inducing remission of PRCA, but many patients with acquired PRCA require immunosuppres- sive therapy to maintain remissions. As summarized in Table I, CS, CsA and CY plus CS are almost equally effective for inducing remissions of PRCA, but the most important difference between these agents is the feasibility of long-term maintenance. Although the relapsed patients can be re-treated with the same agents, such as CS or CS plus CY, the cumulative side effects and toxicity become unacceptable. Considering the recurrent nature of acquired PRCA, we suggest CsA as ﬁrst- line therapy for these patients at a dose of 2Æ5–3 mg/kg twice daily to achieve trough CsA levels of 150–250 ng/ml for a maximum of three to four months. This trough CsA level has been empirically determined according to a consensus from a multicentre randomized study in Japan for aplastic anaemia (Teramura et al, 2007). Maintenance therapy with CsA is a requisite for most patients to prevent relapse. Since nephro- toxicity constitutes the major limiting side effect of CsA, careful and progressive decrease of the dosage to the minimum required for maintenance of remission is appropriate. The mean maintenance dose of CsA in Japanese patients who were continuing their ﬁrst remission for more than 24 months was 2Æ2 ± 0Æ8 mg/kg per day with a range of 1Æ1–3Æ8 mg/kg per day, 40% of the initial dose (Sawada et al, 2007), which suggests difﬁculty in reducing CsA under this dosage to maintain remissions. 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