Calcitonin Gene-related Peptide Antibody in Acute Mountain Sickness

Acute mountain sickness (AMS) is a common condition that can occur when healthy people travel quickly to high altitude. Typical symptoms include headache, nausea, tiredness, dizziness, and poor sleep. In most cases, AMS improves with rest and by not climbing higher, but it can make mountaineering difficult and, in severe cases, can lead to dangerous complications. The biological mechanisms that cause high-altitude headache and AMS are not yet fully understood. Some symptoms of AMS are similar to migraine, suggesting that both conditions may share common pathways in the nervous system. One possible pathway involves calcitonin gene-related peptide (CGRP), a substance known to play an important role in migraine. Fremanezumab is an approved monoclonal antibody used to prevent migraine. It works by binding to CGRP and reducing its biological activity. This study will investigate whether a single dose of fremanezumab can also help prevent symptoms of AMS and high-altitude headache in healthy adults exposed to high altitude. To date, there are no clinical data on the effect of fremanezumab in AMS or high-altitude headache. This is a prospective, randomized, double-blind, placebo-controlled, parallel-group clinical trial. A total of 30 healthy adult volunteers will participate. Participants will be randomly assigned in a 1:1 ratio to receive either a single subcutaneous injection of fremanezumab 225 mg or placebo (saline). Neither the participants nor the investigators will know which treatment was given during the study. The study medication will be administered 1 week before ascent to Capanna Regina Margherita at 4554 meters above sea level. Participants will remain there for 46 hours under hypobaric hypoxic conditions. The main goal is to determine whether fremanezumab reduces the severity of AMS compared with placebo. AMS symptoms will be measured using the Lake Louise Score, a standard questionnaire commonly used in altitude medicine. Additional assessments will include the incidence of AMS, headache characteristics, safety outcomes, vital signs, oxygen saturation, and the use of rescue medication. Symptoms will be assessed repeatedly during the high-altitude stay. Only healthy adults aged 18 to 60 years living below 1000 meters will be eligible. People with important medical conditions, chronic headache or migraine, relevant cardiovascular or lung disease, pregnancy, or recent high-altitude exposure will be excluded. Participants will be closely monitored during the study. Rescue medication, oxygen, and descent to lower altitude will be available if needed. This study may help improve understanding of how AMS develops and whether CGRP blockade could become a new preventive strategy for high-altitude headache and AMS. It may also improve understanding of links between altitude-related headache and migraine.

Inclusion Criteria: * Age 18-60 years * No relevant previous illnesses in the preliminary examination * Written consent to participate in the study * Permanent residence \6 cigarettes/d) or equivalent nicotine substitution * Alcohol (\>30 g/d) or other drug abuse * Overweight (BMI \>30 kg/m2) * Other pre-existing conditions considered relevant by the investigators (liver disease, kidney disease, thyroid disease, Parkinson's disease, pheochromocytoma) * Stay \>2000 m altitude within the last 8 weeks before the first study day * Medication taken within the last 2 months before the first study day, which could influence the data quality (e.g. corticosteroids) or the safety of the subjects (e.g. anticoagulation). * Blood donation within the last 2 months before the first study day * Pregnancy or breastfeeding * Participation in other clinical studies