OBJECTIVETo investigate the effectiveness, safety and possible mechanism of recombinate human interleukin 11 (rhIL-11) in the treatment of chemotherapy-induced thrombocytopenia.

METHODSThirty-four patients (totally 76 cycles) with chemotherapy-induced thrombocytopenia received subcutaneous injection of rhIL-11 at the dose of 25 microg.kg(-1).d(-1) for 4 to 16 days. Serum IL-11 level was measured by ELISA, and IL-11 R alpha expression was detected by RT-PCR.

RESULTSThe mean baseline platelet count before chemotherapy was (135.0 +/- 54.3) x 10(9)/L for the 1st cycle and (259.4 +/- 64.5) x 10(9)/L for the 2nd cycle. The time to administer rhIL-11 was 7 to 16 days (median 12 days) in the 1st cycle and 4 to 10 days (median 6 days) in the 2nd, respectively (P < 0.05). The duration of post-chemotherapy platelet count below 50 x 10(9)/L was 7 to 13 days (median 10 days) for the 1st cycle and 3 to 8 days (median 5 days) for the 2nd, respectively (P < 0.05). Platelet count reached 300 x 10(9)/L or above in 30 chemotherapy cycles. The maximum platelet count was found to appear at D10 to D 17 (median D14), and negatively correlated with the pre-chemotherapy serum IL-11 level after administration of rhIL-11. Major adverse reactions included edema, headache, muscle and joint pain.

CONCLUSIONrhIL-11 is effective and safe for the treatment of chemotherapy-induced thrombocytopenia, with a relatively slow but sustained effect on the recovery of platelet count. Pre-chemotherpy serum IL-11 level might predict the efficacy of rhIL-11.