Somatostatin Analogues are the ‘workhorse’ treatments for those living with NETs, particularly where certain syndromes are involved. So not just for classic NETs with Carcinoid Syndrome but also for treating insulinoma, gastrinoma, glucagonoma and VIPoma (all types of pNETs) and others. They are most effective if the NETs express somatostatin receptors.
Somatostatin is actually a naturally occurring hormone produced by the hypothalamus and some other tissues such as the pancreas and the gastrointestinal tract. However, it can only handle the normal release of hormones. When NET syndromes occur, the naturally occurring somatostatin is unable to cope. The word ‘analogue’ in the simplest of terms, means ‘manufactured’ and a somatostatin analogue is made to be able to cope with the excess secretion (in most cases).
Although there is hidden complexity, the concept of the drug is fairly simple. It can inhibit insulin, glucagon, serotonin, VIP, it can slow down bowel motility and increase absorption of fluid from the gut. It also has an inhibitory effect on growth hormone release from the pituitary gland (thus why it’s also used to treat a condition called Acromegaly). You can see why it’s a good treatment for those with NET syndromes, i.e. who suffer from the excess secretions of hormones from their NETs. Clearly there can be side effects as it also inhibits digestive enzymes which can contribute to, or exacerbate, gastro-intestinal malabsorption.
Please note somatostatin analogues are not chemo. There are two major types in use:
- Octreotide – or its brand name Sandostatin. It is suffixed by LAR for the ‘long acting release’ version.
- Lanreotide – brand name Somatuline (suffixed by ‘Depot’ in North America, ‘Autogel’ elsewhere)
So what’s the difference between the two?
A frequently asked question. Here’s a quick summary:
- They are made by two different companies. Novartis manufactures Octreotide and Ipsen manufactures Lanreotide. Octreotide has been around for much longer.
- The long-acting versions are made and absorbed very differently. Octreotide has a complex polymer and must be injected in the muscle to absorb properly. Lanreotide instead uses has a novel nanotube structure and is water based (click here to see a video of how this works). It is injected deep-subcutaneously and is therefore easier to absorb and is not greatly impacted if accidentally injected into muscle.
- Their delivery systems are mainly via injections but are fundamentally different as you can see from the blog graphic which shows the differences between the long acting release versions. Octreotide long acting requires a pre-mix, whilst Lanreotide comes pre-filled.
- The long-acting versions are 60, 90 and 120 mg for Lanreotide and 10, 20 and 30 mg for Octreotide.
- Octreotide also has a daily version which is administered subcutaneously.
- Octreotide has something called a ‘rescue shot’ which is essentially a top up to tackle breakthrough symptoms. It is a subcutaneous injection.
- You can also ‘pump’ Octreotide using a switched on/off continuous infusion subcutaneously.
- Other than for lab/trial use, to the best of my knowledge, there is no daily injection, rescue shot or ‘pump’ for Lanreotide that is indicated for patient use.
- Whilst both have anti-tumour effects, there are differences in US FDA approval: Octreotide (Sandostatin) is approved for symptom control (not anti-tumor) whereas Lanreotide (Somatuline) is approved for tumour control. However, the US FDA recently added a supplemental approval for syndrome control on the basis that it is proven to reduce the need for short acting somatostatin analogues use – read more here. This supplementary approval followed the ELECT trial – results here.
Here are some interesting videos showing and explaining their administration:
Administering a Somatuline Depot (Lanreotide) injection:
Administering a Sandostatin LAR (Octreotide) injection:
This link also provides guidance on the “new formulation” Octreotide. Click here.
My own experience only includes daily injections of Octreotide (Sep-Nov 2010) and Lanreotide (Dec 2010 onwards). I’ve also had continuous infusion of Octreotide in preparation for surgical or invasive procedures over the period 2010-2012 (i.e. crisis prevention). You can read about my Lanreotide experience by clicking here. If you are interested in what might be coming downstream, please see my blog entitled ‘Somatostatin Analogues and Delivery Systems in the Pipeline’.
Injection site granulomas (lumps)
The issue of ‘granulomas‘ or ‘injection site granulomas’ seems to figure in both drugs. Gluteal injection site granulomas are a very common finding on CT and plain radiographs. They occur as a result of subcutaneous (i.e. intra-lipomatous) rather than intramuscular injection of drugs, which cause localised fat necrosis, scar formation and dystrophic calcification. But no-one seems to know why they occur with somatostatin analogues.
Personally, I find that they are more conspicuous if the injection is done slightly too high which was my initial experience and they took months to fade. I opted to stand up for the first two injections and I attribute this decision for a slightly too high injection site. I now lie down which is actually recommended for the smaller and thinner patient. Although the lumps have reduced in size, I have not seen a new lump for some time indicating location might have been the cause. They sometimes show up on scans. This is not a new problem and has been highlighted for the last 10 years in academic papers. This particular paper is useful and the conclusion confirms this is not something that should worry patients too much. Read more here
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