Protelos - strontium ranelate

What is Protelos?

Protelos is a drug containing the active substance strontium ranelate, available in 2 g sachets containing a granule for oral suspension.

What is Protelos used for?

Protelos is indicated for the treatment of osteoporosis (a disease that makes bones fragile) in women who have passed menopause to reduce the risk of vertebral and hip fractures.

The medicine can only be obtained with a prescription.

How is Protelos used?

The recommended dose of Protelos is one sachet once a day. The contents of the sachet should be mixed in a glass of water to form a suspension to drink immediately after preparation. Protelos should be taken at least two hours after ingestion of food, milk, dairy products or calcium supplements, preferably at bedtime. Protelos is intended for long-term use. Patients being treated with Protelos should receive supplemental calcium or vitamin D if their dietary intake is insufficient.

How does Protelos work?

Osteoporosis occurs when the old bone tissue, which naturally degenerates, is not replaced with sufficient new tissue. Gradually, the bones become thin and brittle, and the chances of fractures increase accordingly. Osteoporosis is more common in postmenopausal women when levels of the female estrogen hormone, the hormone that helps keep bones healthy, fall.

The active substance in Protelos, strontium ranelate, acts on the bone structure. Once the intestine is reached, strontium ranelate releases strontium, a substance that is absorbed by the bones. The mechanism of action of strontium is not entirely known, as far as osteoporosis is concerned, but it reduces bone destruction and stimulates the formation of bone tissue.

What studies have been carried out on Protelos?

Protelos has been examined in two large studies involving nearly 7, 000 elderly women. Just under a quarter of the patients were over 80 years old. The first study involved 1, 649 women with osteoporosis with previous vertebral fractures, while the second study was carried out on over 5, 000 women with osteoporosis located in the hip and femur region. In both studies the efficacy of Protelos was compared with a placebo (a dummy treatment) and the main measure of effectiveness was the reduction of the risk of a new bone fracture with Protelos. In the first study, this parameter was the number of patients who, over the course of three years, had developed a new vertebral fracture and, in the second study, the parameter was the number of patients who underwent a new peripheral fracture (non vertebral ) due to osteoporosis.

What benefit has Protelos shown during the studies?

In the first study, Protelos was effective in reducing the risk of new vertebral fractures by 41% over three years: 21% of the 719 women treated with Protelos developed a new vertebral fracture compared to 33% of 723 patients treated with placebo.

Overall, the results of the second study alone were not sufficient to demonstrate the benefits of Protelos in the prevention of peripheral fractures. However, if only women of 74 years of age or older with a marked fragility of the femur are considered, the results indicate a reduction in the risk of hip fractures when taking Protelos.

Looking at the results of both studies together, fewer women in the Protelos group developed peripheral fractures in parts of the body other than the spine (including the hip) compared to the placebo group (331 out of 3 295 of group treated with Protelos compared to 389 out of 3 256 in the placebo group), thus demonstrating a reduction in the risk of fracture.

What is the risk associated with Protelos?

The most common side effects reported with Protelos (observed in a number of patients between 1 and 10 out of 100) are headache, consciousness disturbances (fainting), memory loss, nausea, diarrhea, loose stools, dermatitis (skin inflammation ), eczema (scaly rash), venous thromboembolism (blood clots in the veins) and increased levels of creatine kinase (an enzyme present in muscle tissue) in the blood. For the full list of all side effects reported with Protelos, see the Package Leaflet.

Protelos should not be used in people who may be hypersensitive (allergic) to strontium ranelate or any of the other components.

Why has Protelos been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that the benefits of Protelos outweigh its risks in the treatment of osteoporosis in postmenopausal women to reduce the risk of vertebral and hip fractures. The Committee therefore recommended that Protelos be given marketing authorization.

Other information about Protelos:

On 21 September 2004, the European Commission issued a marketing authorization for Protelos to Les Laboratoires Servier, valid throughout the European Union. The marketing authorization was renewed on 21 September 2009.

The full EPAR for Protelos can be found here.

Last update of this summary: 09-2009.