Shares in NicOx sank nearly 35% following news that the French drugmaker has pulled back a European filing seeking to market its painkiller Beprana for osteoarthritis of the knee and hip.

The company was intending to market Beprana (naproxcinod) for the relief of signs and symptoms associated with these conditions, but decided to withdraw its application after European regulators said the data it has provided in the submission "do not allow it to conclude on a positive benefit-risk balance".

Despite the blow NicOx said it is now evaluating its options for the potential further development of Beprana in Europe alongside its own advisors and with Grupo Ferrer Internacional, which has an option for rights to the drug in certain European territories.

But some analysts fear Beprana's future is bleak, particularly as the US Food and Drug Administration rejected the drug last year recommending further clinical trials. 

NicOx is currently appealing this decision, but analysts believe the chances of the rejection being overturned are minimal.

An anonymous Paris, France-based analyst told Reuters that Beprana is "dead", adding that "now it will be wait and see what steps management will take next, how they could approach potential merger partners."