Octreotide and Lanreotide are medicines that are called "Somatostatin Analogues". They are synthetic versions of a natural hormone we all make called somatostatin. It's like the brake pedal of your body. It slow digestion, hormonal function, and a lot more. Unfortunately, the natural stuff only lasts 2 minutes and is broken down quickly. Octreotide and lanreotide, on the other hand can last for 4-6 hours, and when given in the depot version, last for a month. Both medicines bind to the somatostatin receptor on NETs and help them to both decrease hormone secretion and growth. Their bindings are very similar, but not exactly the same, so they may have slightly different effects in individuals, but not by much.
The biggest difference is in the formulation of the medications and the research that was performed on them. Octreotide (Sandostatin) has been the workhorse medication for NET patients for the past 25 years. It was truly a blessing for many patients. It comes as a short acting version which is given as "little shots", but only last 4-6 hours. The big shot is given monthly in the big muscle of the buttock to help it absorb over about 28 days. Unfortunately, it has been a difficult medication to mix-up and administer. It comes as a complex polymer and must be injected in the muscle. If it does not get there, it gels up like a rock and the medicine is never really absorbed. It comes as 10, 20, 30 mg.
Lanreotide (Somatuline), on the other hand is much more forgiving. It is a "deep subcutaneous" injection, which means that it can go into muscle or fat. It does not have polymers so it can be absorbed more easily because it has a novel nanotubule structure and is water based. It seems to have a steadier release also. It's also MUCH easier for the nurse to mix and administer. It comes prepackaged and just needs to be brought up to body temperature and injected. It comes as 60, 90, 120 mg.
There are slight differences in FDA approval: octreotide (Sandostatin) is approved for symptoms of carcinoid/VIPoma syndrome and Lanreotide (Somatuline) is approved for tumor control.
In my opinion, it is best to have options. If you've been on Sandostatin and it's working, no need to rock the boat. If it has been difficult to mix, administer, and absorb, then Somatuline might be a better option. If you've had bad reactions to either, the other might work better. I'm always happy to have more tools to help NET patients live better, longer lives.
Eric Liu, M.D.