Evaluation of injection-site-related adverse events with galcanezumab: a post hoc analysis of phase 3 studies in participants with migraine



Injection-site reactions have been reported with biologicals. In this post hoc analysis of Phase 3 studies in participants with migraine, we provide a comprehensive overview and detailed summary of injection-site reaction with galcanezumab.


Data were obtained from two randomised clinical studies in participants with episodic migraine (EVOLVE-1 and EVOLVE-2), one randomised study in participants with chronic migraine (REGAIN) and one open-label study (Study CGAJ) in participants with episodic or chronic migraine. The injection-site reactions were measured for two different cohorts: 1) six-month double-blind treatment phase in the EVOLVE-1 and EVOLVE-2 studies and three-month double-blind treatment phase in the REGAIN study, where participants received placebo and galcanezumab (placebo-controlled analysis set); 2) three month double-blind (Month 0 to Month 3; 1:1:placebo:galcanezumab) + 9 months open-label extension phase (Month 3 to Month 12) of REGAIN and twelve month open-label phase of Study CGAJ, where participants received only galcanezumab (galcanezumab exposure analysis set).


A total of 477 participants in the placebo-controlled analysis set (galcanezumab 240 mg, 166/730 [22.7%]; galcanezumab 120 mg, 128/705 [18.2%]; placebo, 183/1451 [12.6%]) reported at least one injection-site reaction. Most of the injection-site reactions were reported as injection-site pain, unspecified injection-site reaction, injection-site erythema, and injection-site pruritus. The incidence of injection-site pain was highest among all reported injection-site reactions and were reported with similar frequency by participants receiving galcanezumab (galcanezumab 120 mg, 10.1%; galcanezumab 240 mg, 11.6%) and placebo (9.5%) and was the most common injection-site reaction reported within 60 min of injection (~ 86% of participants). The frequency of unspecified injection-site reaction, injection-site erythema and injection-site pruritus was significantly (P < 0.001) higher in participant receiving galcanezumab versus placebo. In the galcanezumab exposure analysis set participants received up to 12 doses and the frequency of injection-site reactions reported for both doses combined was 21.8%. The reporting of injection-site reactions did not increase with the number of doses received. No ISR-related serious adverse events were reported in both the placebo-controlled and galcanezumab exposure analysis sets.


The most common adverse event of galcanezumab is injection-site reactions. However, these events were generally mild-to-moderate in severity, non-serious, resolved spontaneously, and discontinuations due to injection-site reactions were low (1%).



Background
People with migraine have been shown to have elevated blood levels of calcitonin gene-related peptide (CGRP) and targeting the CGRP pathway using antibodies has been demonstrated to be effective in preventing migraine attacks [1][2][3][4]. Three such biological therapies including galcanezumab have been approved as preventive treatments for migraine [5]. Galcanezumab, erenumab and fremanezumab are administered subcutaneously, and adverse events (AEs) related to injection-sites were the most frequently reported AEs in their respective Phase 3 programs [6][7][8]. Injection-site reactions are local skin reactions occurring after an injection and include injection-site pain, erythema, pruritus and induration [6][7][8]. The aetiology of injection-site-related adverse events maybe multifocal, ranging from immunological to non-immunological factors including injection volume, temperature, pH, speed of injection, needle size, and injection excipients [9,10].
Therefore, in this post hoc analysis of Phase 3 migraine studies of galcanezumab, we provide a comprehensive overview and detailed summary of injection-site reactions.
Briefly, EVOLVE-1 and EVOLVE-2 studies had a 6month double-blind (DB) treatment phase wherein participants were randomised 2:1:1 to receive monthly placebo, galcanezumab 120 mg or galcanezumab 240 mg. The RE-GAIN study had a 3-month DB treatment phase, wherein participants were randomised 2:1:1 to receive monthly placebo, galcanezumab 120 mg, or galcanezumab 240 mg. The DB phase was followed by an optional nine month openlabel extension (OLE) phase wherein either galcanezumab 120 mg or galcanezumab 240 mg was administered based on the investigator's discretion. Study CGAJ comprised a 12-month open-label (OL) phase wherein participants were randomised 1:1 to receive galcanezumab 120 mg or galcanezumab 240 mg. All four studies had a four-month safety follow-up period immediately after the treatment phase.
In the EVOLVE and REGAIN studies, study site personnel administered the injections using prefilled syringes. In Study CGAJ, injections were self-administered by participant or caregiver using prefilled syringes for up to 9 months, and then participants were switched to self-administer galcanezumab using an autoinjector [15]. Notably the autoinjector was not available for administration at the time of study initiation and was available approximately 1 year after the start of the study. As such all participants in Study CGAJ used an autoinjector from approximately Month 10 onwards. All participants and caregivers in the Study CGAJ who continued the treatment were trained to use the autoinjector before switching at Month 9 [15].

Evaluation of injection site reactions
Two cohorts from the integrated analysis sets of four studies (EVOLVE-1, EVOLVE-2, REGAIN and CGAJ) were analysed. These studies included: 1) all participants from the six-month DB treatment phase in the EVOLVE-1 and EVOLVE-2 studies and three-month DB treatment phase in the REGAIN study (placebo-controlled analysis set); 2) galcanezumab-treated participants from the DB + OLE phase of REGAIN, Month 0 to Month 12, and OL phase of Study CGAJ, Month 0 to Month 12, where participants received galcanezumab (galcanezumab exposure analysis set). Of note, participants who were randomized to placebo in the REGAIN study received up to 9 monthly doses of galcanezumab and participants who were randomized to galcanezumab received up to 12 monthly doses of galcanezumab.
The injection-site reactions are treatment-emergent adverse events (TEAEs) that occurred or worsened at any time after treatment initiation and were coded based on the Medical Dictionary for Regulatory Activities (https://www.med dra.org/). The injection-site reactions (plural) refer to the high-level grouping of different preferred terms (PT) used to describe various injection-site reactions. The reported verbatim terms collected during the study was mapped to a PT that best characterised the reported adverse event at the injection-site, such as "pain", "erythema", "rash" and "swelling". When the site recorded the event as "injection-site reaction" the event was mapped to an unspecified PT of injection-site reaction (singular). An injection-site adverse event follow-up form was used to further characterise the reported unspecified event of injection-site reaction.

Statistical analysis
The placebo-controlled analysis set was used to evaluate injection-site reactions for up to six-month of DB treatment and the galcanezumab exposure analysis set was used to evaluate injection-site reactions up to 12 months of galcanezumab treatment.
For both analysis sets, the number of participants with injection-site reactions, discontinuations due to AEs, and serious AEs (SAEs) were summarized. For the placebocontrolled analysis set, inferential statistics was provided. Treatment comparisons were evaluated using the Cochran-Mantel-Haenszel test stratified by study. In addition, patients with injection-site reactions were summarized by maximum severity as "mild", "moderate" or "severe". The reaction timings from the last injection to the occurrence of injection-site reactions were summarised as follows: immediate reaction (< 60 min); acute reaction (1 to 6 h); delayed reaction (classified as injection-site reactions post 6 h on the day of the injection up to 14 days after the day of injection); and reactions ≥14 days. The duration of injection-site reactions were also summarized.
For the galcanezumab exposure data set, to determine if injection-site reactions excluding pain were reported more frequently with repeated doses of galcanezumab, the number of TEAEs were assessed by the total number of doses received.
Among patients who reported injection-site reactions, most reported injection-site reactions of mild-to-moderate severity (Table 3). No injection-site reactions were reported as SAEs. Overall seven participants discontinued due to injection-site reactions (galcanezumab 120 mg, n = 2; galcanezumab 240 mg, n = 5). Among these participants, four participants discontinued due to moderate unspecified injection-site reaction (galcanezumab 120 mg,  Table 3. Injection-site pain was the most common immediate injection-site reaction reported within 60 min of injection) and was observed in approximately 86% of participants reporting injection-site pain ( Table 4). Majority of unspecified-injection-site reaction (placebo, 100.0%; galcanezumab, 88.0%), injection-site erythema (placebo, 95.0%; galcanezumab, 79.0%) and injection-site pruritus (placebo, 100%; galcanezumab. 74.4%) occurred on the day of injection (  Table 5). Overall nine patients discontinued the treatment due to injection-site reactions (Study CGAJ, Abbreviations: GMB galcanezumab, ISR injection-site reaction, N number of participants in the intent-to-treat population, n number of participants within each specific category, SD standard deviation a N = 729 Note: All values are for injection-site reactions during the double-blind treatment phase from study start up to 6 months for EVOLVE-1 and EVOLVE-2 and up to 3 months for REGAIN n = 5; REGAIN, n = 4). All discontinuations were observed following multiple doses of galcanezumab (fourth, n = 1; fifth injection, n = 1; sixth injection, n = 1; seventh injection, n = 3; ninth injection, n = 1; 10th injection, n = 2). To evaluate if galcanezumab-treated patients reported multiple injection-site reactions (excluding pain) over consecutive monthly injections, the number of TEAEs related to injection-sites (excluding pain) by total number of doses is provided in Table 6. In summary 81% of patients received 9 doses or more of galcanezumab and most patients reported 1 to 3 events with monthly injections over 9 to 12 months suggesting that the reporting of injection-site reactions (excluding pain) did not increase with multiple dose administrations.

Discussion
In Phase 3 studies demonstrating efficacy and safety of galcanezumab as a treatment option for management of migraine, injection-site reactions were the most commonly reported AEs. The incidence of injection-site pain was highest among all reported injection-site reactions and was reported equally by participants receiving galcanezumab and placebo. Unspecified injection-site reaction, injection-site erythema and injection-site pruritus were significantly (P < 0.001) higher in participants being treated with galcanezumab compared with placebo. Overall, the incidence of injection-site reactions were higher in the galcanezumab dose groups (240 mg > 120 mg) compared with placebotreated participants and appear to be driven by AEs related to injection-sites including unspecified injection-site reaction, injection-site erythema, and injection-site pruritus. These reactions are commonly observed with other approved monoclonal antibodies for subcutaneous use, including adalimumab, denosumab, ixekizumab, and canakinumab [16][17][18] as well as CGRP monoclonal antibodies [7,19,20].
In this post hoc analysis of four Phase 3 studies, we provide a more comprehensive summary of injectionsite reactions with short-term and long-term exposure

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Abbreviations: AE adverse events, GMB galcanezumab, IS injection-site, ISR injection-site reaction, N number of participants in the safety population, n number of participants within each specific category, SAE serious adverse event, SD standard deviation, TEAE treatment-emergent adverse event a one galcanezumab 240 mg participant discontinued due to injection-site swelling Note: All values include AEs related to ISR during the double-blind treatment phase from study start up to 6 months for EVOLVE-1, and EVOLVE-2 and up to 3 months for REGAIN Table 4 Time to onset of injection-site reactions in pooled EVOLVE-1, EVOLVE-2 and REGAIN (placebo-controlled analysis set)

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Abbreviations: GMB galcanezumab, IS injection-site, ISR injection-site reaction, n number of patients with non-missing reaction timings Note: All values are for ISR during the double-blind treatment phase from study start up to 6 months for EVOLVE-1 and EVOLVE-2 and up to 3 months for REGAIN to galcanezumab. Of the most commonly reported injection-site reactions in galcanezumab-treated participants, 70 to 100% were reported on the day of injection, were generally mild-to-moderate in severity, non-serious, and resolved spontaneously. In total 16/1705 (< 1%) treatment discontinuations were observed due to injection-site reactions; seven were observed in placebo-controlled analysis set and nine (Study CGAJ, n = 5; REGAIN, n = 4) were observed in the galcanezumab exposure analysis set. Most participants reported onset of injection-site pain within 60 min of injection, and approximately 50% of injection-site pain was reported as injection-site burning.
Of interest, 17.5% of patients reported a history of hypersensitivity, however only 5.2% of those patients reported injection-site related AEs other than pain. During exposure to galcanezumab up to 12 months of treatment, the number of injection-site reactions reported by the same patient does not increase with more doses received.
Notably, therapeutic monoclonal antibodies (mAb), including galcanezumab, have the potential to have antidrug antibody (ADA) formation, which in turn can block the active mAb site. The formation of ADA can be associated with changes to pharmacokinetic and pharmacodynamic parameters, resulting in a range of effects from no clinically important effects to reduced drug efficacy and/or increased risk of adverse events (AEs) [21,22]. A recently published post hoc analysis of EVOLVE-1, EVOLVE-2, REGAIN and CGAJ studies, showed that approximately 2.6 to 12.4% of galcanezumab-treated patients developed treatment-emergent ADA. The characteristics of the immune response observed were not related to any clinically meaningful consequences on pharmacokinetic, pharmacodynamics, efficacy, or safety of galcanezumab. There were no differences in injectionsite reactions reported in patients who developed treatment emergent ADA compared to those who did not.
Therapeutic proteins are typically administered in the subcutaneous tissue, especially when the treatment is required frequently, on a long-term basis and requires self-administration [23]. Injection-site reactions with therapeutic proteins may arise from participant-related factors such as variability in injection speed (association of injection-site pain with fast injections), participant-toparticipant differences in pain tolerance. The injectionsite reactions with therapeutic proteins may also arise from variations in formulation-related factors such as formulation temperature (which should ideally be close to body temperature), type of injectable device used (prefilled syringe versus autoinjector), injection volume (ideally should be ≤3 mL [24]), pH (ideally should be physiological) and excipients [23,25]. For galcanezumab, the pH of the formulation is between 5.3 and 6.3, the injection volume is 1 mL, the inactive excipient contains polysorbate 80, L-histidine, histidine hydrochloride monohydrate, and sodium chloride [26]. During shortterm exposure to galcanezumab, we observed similar incidence of injection-site pain between placebo-and galcanezumab-treated participants. This may explain the possibility that formulation-based factors, such as nonphysiological pH (i.e. < 7) and presence of polysorbate   , who have cited injection-site pain associated with Kineret (anakinra) owing to its non-physiological pH and presence of polysorbate 80 in the formulation [25,27]. This post hoc analysis, which was not pre-specified at the time of design of the EVOLVE-1, EVOLVE-2, RE-GAIN and Study CGAJ, limits its ability to make definitive conclusions. There could also be some under-reporting possibly as all AEs were reported spontaneously by the study participants, and use of analgesic, and histamine creams, and potential comfort measures were not excluded. Lastly, galcanezumab injections were administered by study site personnel in the galcanezumab Phase 3 studies, with the exception of Study CGAJ. In Study CGAJ, patients self-administered galcanezumab either with the prefilled syringe or the autoinjector devices. The injection experience and tolerability of self-administration with both devices has been published elsewhere [15].

Conclusions
In conclusion, galcanezumab-treated participants reported a significantly higher frequency of injection-site reactions versus placebo. Most of these events were self-limiting; no SAEs related to injection-site were reported in any of the Phase 3 migraine studies. Future post-marketing study evidence is warranted to augment these findings.
Additional file 1. List of ethics committee.