Biosimilars of Rituxan, MabThera, Herceptin and Erbitux will erode $8.2 billion in US and European sales in 2018

The US and European (France, Germany, Italy, Spain and U.K.) sales of Roche/Biogen Idec's Rituxan/MabThera (rituximab), Bristol-Myers Squibb/Merck' KGaA's Erbitux (cetuximab) and Roche's Herceptin (trastuzumab) will peak at almost $16 billion in 2014, before falling to roughly $10 billion in 2018, according to forecasts by research and advisory firm Decision Resources. Biosimilars ' generic versions 'of these three branded agents are forecasted to erode $8.2 billion in US and European sales in 2018 but they are expected to capture only $4.6 billion in sales due to their lower prices.

"Biosimilars of the five brands covered in this report (Rituxan/MabThera, Erbitux, Herceptin, Amgen's Neupogen (filgrastim) and Neulasta (pegfilgrastim) will erode $34.3 billion in brand sales during our 2008-2018 forecast period across the USA and Europe and save health care systems $17.3 billion in the process," stated Michael Malecki, analyst and product manager at Decision Resources.

The new special report entitled Biosimilars: G-CSFs and Monoclonal Antibodies in Oncology also finds that oncologists are expected to demand clinical data for biosimilars demonstrating equivalence in multiple subpopulations. That is, although a biosimilar may be labeled for use in multiple sub-populations, oncologists will not feel comfortable prescribing a biosimilar without clinical validation.

Over time, oncologists are expected to become more comfortable using biosimilars in sub-populations and/or indications for which the reference product is approved but not clinically validated. In order to slow the growth of physician comfort in this regard, makers of branded biologics should emphasize the proven efficacy records of their agents and the importance of using a fully validated therapy for patients with life-threatening disease.

"Although surveyed oncologists are the most aggressive in treating cancers, they are hesitant to prescribe a biosimilar if it has not been clinically studied for the indication they are treating, even if the biosimilar is labeled for the indication in question," added Dr Malecki.