Swiss drugmaker Novartis and US biopharma Amgen are embroiled in a legal dispute regarding their collaboration on migraine prevention drug Aimovig.

Novartis has filed a complaint in a Manhattan federal court, alleging that Amgen is trying to “unjustifiably” end their collaboration. The company is asking the court to confirm that Amgen has no right to end the agreement, saying that it considers the termination is “without legal merit.”

Amgen has countersued, stating that Novartis has breached their agreement because the Basel-based company’s Sandoz division has formed a manufacturing partnership with potential rival AlderBiopharmaceuticals to develop, manufacture and market a competing drug.

The collaboration remains in place until a final and binding court decision is made to terminate the agreements.

Amgen originally had rights to Aimovig but partnered in August 2015 with Novartis, which said it has spent $870 million on development and commercialization since then. The companies have co-commercialization rights for Aimovig in the US, while Amgen retains exclusive commercialization rights in Japan with Novartis holding the rights to markets in Europe, Canada and the rest of the world.

Aimovig won approvals last year in Europe and the USA for the preventative treatment of migraine in adults.

Separately, Novartis completed the spin-off of its Alcon eye care business on Apr. 9. The spin-off, said Novartis, gives it a financial profile closer to its pharmaceutical industry peers, including higher group margins.

The Swiss pharma noted that it anticipates launching 10 potential blockbuster drugs in the next two years, with a further 20 on the horizon.  Four launches are planned in 2019, including RTH258 (brolucizumab) for treating age-related wet macular degeneration.

RTH258 is part of the ophthalmology pharmaceuticals business that Novartis retained. The business, which had sales of $4.6 billion in 2018, has a pipeline of potential novel treatments for presbyopia, dry eye and genetic diseases.