Updated from 8:54 a.m. EDT

Human Genome Sciences ( HGSI) said Monday that its long-acting interferon cured hepatitis C patients at statistically comparable rates to the current standard of care, and with only half the required injections, according to final data from a phase III study.

However, treatment with Human Genome Sciences' drug, known as Albuferon, resulted in numerically fewer hepatitis C cures than did treatment with Roche's interferon Pegasys. Albuferon also caused more serious side effects than Pegasys, according to data from the study.

Albuferon is a longer-acting form of interferon that can be given to hepatitis C patients every two weeks. Current interferons -- Pegasys from Roche and Schering-Plough's ( SGP) PEG-Intron -- require weekly injections.

Human Genome Sciences and Novartis ( NVS) are co-developing Albuferon. The companies plan to seek regulatory approval for the drug in the fall, based on the results from the phase III study released.

The trial, known as ACHIEVE 1, showed that 48.2% of hepatitis C patients treated every two weeks with Albuferon plus ribavirin for 48 weeks achieved a clinical cure. This compared with 51% of patients treated with Pegasys and ribavirin. While Albuferon produced a numerically lower cure rate, the results were statistically comparable, which met the primary endpoint of the study, according to Human Genome Sciences.

The rate of serious adverse events in the study was 24% for the Albuferon patients compared with 23.1% for Pegasys patients. For serious and/or severe pulmonary side effects, the rate was 1.8% for Albuferon patients and 1.1% for Pegasys patients.

The discontinuation rate for Albuferon patients was 10.4% in the study compared to 4.1% for Pegasys patients.

Human Genome Sciences shares closed Friday at $1.70 a share.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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