Got a response from Sanofi
Storage of Lantus Solostar pens
Lantus SoloStar pens which have not yet been used should be stored in the refrigerator (between 2°C and 8°C) to maintain their storage life of 3 years. They should be kept inside the box to protect them from light. Do not freeze them or keep them near the freezer compartment of the refrigerator.
Before using your Lantus SoloStar pen that has been kept in the refrigerator, it should be left at room temperature (up to 25°C), for one to two hours. Once you have started using the SoloStar pen, it is advisable to leave it at room temperature as constantly removing the device from the refrigeration temperature to room temperature can affect the mechanics of the pen.
Once Lantus Solostar pens are removed from the fridge they can be kept and used for 28 days at a temperature up to 25°C. Do not use Lantus if it has been kept for longer than 28 days out of the refrigerator or if the temperature has exceeded 25°C.
I hope that the information is of interest to you. If you have any further enquiries regarding Lantus SoloStar then please contact us.