[Telbivudine-associated creatine kinase elevation in chronic hepatitis B patients]

To evaluate the occurrence and prognosis of telbivudine (LdT) therapy-associated elevations in creatine kinase (CK) in chronic hepatitis B (CHB) patients.

Forty-nine patients treated with LdT from 2004 to 2010 were evaluated for development of CK elevation. In particular, the occurrences of grade 3/4 CK elevations (7-times the upper limit of normal (ULN)) and muscle damage were assessed over duration of the LdT treatment.

The rate of CK elevation increased with duration of LdT treatment (1 year: 61.2%; 5 years: 95.9%). In addition, the severity of CK elevation showed a trend for increasing with duration of LdT treatment, with grade 1/2 CK elevations increasing from 57.1% at year 1 to 81.6% at year 5 and grade 4 increasing from 4.1% at year 1 to 14.3% at year 5. Grade 3/4 CK elevations were observed in seven patients between LdT treatment weeks 36 and 168, but occurred most frequently between weeks 52 and 104, when the maximum peak value occurred (35.8-times the ULN). LdT treatment was stopped in two patients due to excessive CK elevation and one patient due to myositis. The majority of cases of LdT-associated grade 3/4 CK elevations were self-limiting, transient (decreasing to grades 0 or 2 within 2-3 weeks), and present without myalgia.

Elevation of CK was not rare in CHB patients treated with LdT, but most cases resolved spontaneously. In general, the severity and persistence of CK elevation was not sufficient to warrant withdrawal of LdT.