The investigators will treat patients (targeting enrollment of n=20) who suffer from trigeminal or glossopharyngeal nerve pain in the context of painful small fiber neuropathy. The primary pain-related objective is reduction of pain and reduced use of rescue and other anti-pain medications. Another goal is to monitor and confirm the safety profile established in the migraine population, during previous Phase 3 trials.

Inclusion Criteria:

• Age 18-80 years old.
• The patient must have an assigned diagnosis of non-neuralgic trigeminal nerve pain G50.1, with all its permutations listed in the ICD10 explicitly allowed. Co-morbid trigeminal neuralgia G50.0 and G43. … related headache codes are allowed. As an alternative to trigeminal nerve pain G50.1, glossopharyngeal nerve pain will be another inclusion criterion, with a G52.1 diagnosis and explicit mentioning of pain mediated by or in the innervation territory of the glossopharyngeal nerve.

In addition, patients have to be diagnosed with a painful small fiber neuropathy. This diagnosis is based on a skin biopsy or biopsy of an innervated surface epithelium with nerve fiber density count. The required ICD10 diagnostic codes are G63.3, G60.8, G62.8. Co-morbidity with a fibromyalgia-related disorder will be allowed, typically summarized under a diagnosis code of M79.7.

Exclusion Criteria:

• Patients that have a history of allergy or allergy-like incompatibility with a biologic that contains a human or humanized monoclonal antibody will be excluded.
• Female patients of child-bearing age who are or want to become pregnant will be excluded. In case such a patient intends to participate, then she has to commit to a pregnancy prevention regimen that is based on hormonal contraceptive or intra-uterine device.

180 days

Patient adverse events were collected from week 4 week observation period to Day 180+/-3 days. Patients were systematically asked via patient diary and regular investigator assessments. Investigator assessments were administered at week 4 of observation period, day 30, day 45, phone call #1 between days 45 and 60, day 60, day 75, phone call #2 via days 75 and 90, day 105, day 135, and day 180. In addition, patient was able contact investigator or research coordinator in between assessments.