Peginterferon alfa-2b/Ribavirin(Merck & Co., Inc.)

Temozolomide (TMZ) is an oral alkylating agent used in the treatment of central nervous system neoplasms and metastatic melanoma. Preclinical and clinical data suggested that combining TMZ with interferon alpha-2b (IFN-alpha-2b) may result in increased anti-tumour efficacy.

This was a phase I, dose-escalation study to define the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of cyclical oral TMZ (days 1-7 and 15-21) in combination with pegylated IFN-alpha-2b (PEG-IFN-alpha-2b) in patients with advanced solid tumours.

We treated 19 patients (10 female and nine male), median age 58 years (range: 41-79 years). Ten patients tolerated TMZ at 100 mg/m² on days 1-7 and 15-21 plus PEG-IFN-alpha-2b at 1.5 mcg/kg/week on 28-day cycles which was the MTD of the combination. The pharmacokinetic parameters of PEG-IFN-alpha-2b were not altered by TMZ, at the MTD.

The MTD of cyclical oral TMZ was 100 mg/m² on days 1-7 and 15-21 when combined with weekly subcutaneous PEG-IFNα-2b at 1.5 mcg/kg/week on 28 days cycles. The PK of PEG-IFN-alpha-2b appeared consistent with those when it is used as monotherapy.

A 62-year-old woman with a past history of chronic hepatitis C virus infection presented an atypical predominantly painful polymyositis following a flu-like syndrome, persisting despite the withdrawal of PEG-interferon alpha-2b therapy. Clinical assessment, then immunological, electrophysiological and iconographic investigations including myositis antibodies, electromyography, pulmonary functions assessment and thoracic CT-scan found respectively "mechanic hands", arthralgia, presence of antisynthetase anti-PL7 antibody, typical myographic features of hip and shoulder girdles involvement, pulmonary fibrosis and restrictive syndrome features. A deltoid muscle biopsy revealed an unclassified myositis getting closer to anti-J0-1 and connective tissue disease associated myositis featuring: some components of polymyositis, dermatomyositis, and the following peculiar pathological aspects: noncaseous granulomatous infiltrate, endomysial microangiopathy and vascular and sarcolemic deposition of complement membrane attack complex. The diagnosis of interferon induced anti-PL7 antisynthetase syndrome with microangiopathic and granulomatous overlap myositis was retained. A treatment associating intravenous immunoglobulin and moderate tapered oral corticosteroids allowed a complete long-term resolution of myositis and a clear improvement of pulmonary involvement. This case points out the wide range of interferon alpha-associated disorders and call for a precise and detailed immunopathological analysis of myositis, instead of the usual vague classification as idiopathic polymyositis or dermatomyositis about antisynthetase syndrome.