Short answer: Usually a few percent more than placebo. The labels report injection site reactions in 7.2% on Praluent vs 5.1%, 3.2% on Repatha vs 3.0%, and 4.9% on Evenity vs 2.8% on its comparison group. Leqvio, which is not an antibody, reports 8% vs 2%. Redness, pain, itching, swelling and bruising are the usual signs, and few people stopped because of them.
Praluent (alirocumab), Repatha (evolocumab), Evenity (romosozumab) and Prolia (denosumab) are monoclonal antibodies given under the skin. Leqvio (inclisiran) is a small interfering RNA, included here because it is often compared with the PCSK9 antibodies.
| Medicine and trials | Medicine | Comparison | Stopped because of it |
|---|---|---|---|
| Praluent 75 or 150 mg every 2 weeks, pooled placebo trials | 7.2% | 5.1% placebo | 0.2% vs 0.4% |
| Praluent 300 mg every 4 weeks (48-week trial) | 16.6% | 7.9% placebo (9.6% on 75 mg) | 0.7% vs 0% |
| Praluent, ODYSSEY OUTCOMES | 3.8% | 2.1% placebo | 0.3% vs under 0.1% |
| Repatha, 8 pooled trials | 3.2% | 3.0% placebo | 0.1% vs 0% |
| Evenity, 2 trials in women with osteoporosis | 4.9% | 2.8% control | 0.1% vs under 0.1% |
| Leqvio, 3 trials (not an antibody) | 8% | 2% placebo | 0.2% vs 0% |
The Praluent label adds that people on Praluent had more reactions, more symptoms with them, and reactions that lasted longer on average than on placebo. The 300 mg dose is given as two 150 mg injections at two different sites, which may be part of why its rate is higher. Prolia lists injection site reactions among reports after approval, without a rate.
The labels name the same few signs: redness (erythema), pain or tenderness, itching, swelling and bruising. On Evenity, the most common were pain (1.7% vs 1.3%) and redness (1.4% vs 0.3%). On Repatha, redness, pain and bruising.
A local reaction is different from an allergic reaction. The Praluent and Repatha labels warn about allergic reactions, including swelling under the skin (angioedema), and the Evenity label warns about hives, rash and angioedema. Swelling of the face, lips, tongue or throat, trouble breathing, or a widespread rash is the kind of reaction the labels say to stop for and get treated right away.
The Praluent and Repatha labels say to inject into the thigh, abdomen or upper arm, into skin that is not tender, bruised, red or hard, and to rotate sites at each dose. Repatha adds avoiding scars and stretch marks; Evenity gives the same skin rules and says to choose a different spot each time. The Leqvio instructions say not to inject into areas of active skin disease or injury such as sunburn, rashes, inflammation or infection.
Several of these labels also ask for a warm-up out of the fridge before injecting; see should injections warm to room temperature.
A reaction that keeps coming back, grows from one dose to the next or does not fade is worth showing to the prescriber. Dose Track logs the site of every injection and can attach a side-effect note to the dose, so it is clear which spots reacted and when.
Read more on Dose Track: Injection site reaction · Praluent side effects · Repatha side effects · Evenity side effects · Injection site rotation guide