International, multicenter, Phase IIIb study of subcutaneous every-other-day treatment of patients with relapsing multiple sclerosis with (Phase A) double-blind Betaseron/Betaferon 250 µg or 500 µg or open-label Betaseron/Betaferon 250 µg and (Phase B) open-label Betaseron/Betaferon 500 µg version: final internal approved