Zolmitriptan (Page 5 of 7)

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

Zolmitriptan was administered to mice and rats at doses up to 400 mg/kg/day. Mice were dosed for 85 weeks (males) and 92 weeks (females); rats were dosed for 101 weeks (males) and 86 weeks (females). There was no evidence of drug-induced tumors in mice at plasma exposures (AUC) up to approximately 700 times that in humans at the maximum recommended human dose (MRHD) of 10 mg/day. In rats, there was an increase in the incidence of thyroid follicular cell hyperplasia and thyroid follicular cell adenomas in male rats receiving 400 mg/kg/day. No increase in tumors was observed in rats at 100 mg/kg/day, a dose associated with a plasma AUC≈700 times that in humans at the MRHD.

Mutagenesis

Zolmitriptan was positive in an in vitro bacterial reverse mutation (Ames) assay and in an in vitro chromosomal aberration assay in human lymphocytes. Zolmitriptan was negative in an in vitro mammalian gene cell mutation (CHO/HGPRT) assay and in oral in vivo micronucleus assays in mouse and rat.

Impairment of Fertility

Studies of male and female rats administered zolmitriptan prior to and during mating and up to implantation showed no impairment of fertility at oral doses up to 400 mg/kg/day. The plasma exposure (AUC) at this dose was approximately 3000 times that in humans at the MRHD.

14 CLINICAL STUDIES

14.1 Adults

The efficacy of zolmitriptan nasal spray 2.5 mg and 5 mg in the acute treatment of migraine headache with or without aura in adults was demonstrated in Study 1, a randomized, outpatient, double-blind, placebo-controlled trial.

In Study 1, patients were instructed to treat a moderate to severe headache. Headache response, defined as a reduction in headache severity from moderate or severe pain to mild or no pain, was assessed 15, 30, 45 minutes and 1, 2, and 4 hours after dosing. Pain-free response rates and associated symptoms such as nausea, photophobia, and phonophobia were also assessed. A dose of escape medication was allowed 4 to 24 hours after the initial treatment for persistent and recurrent headache.

In Study 1, of the patients taking zolmitriptan nasal spray 2.5 mg or 5 mg, 83% were female and 99% were Caucasian, with a mean age of 41 years (range 18 to 65 years).

The two-hour headache response rates in patients treated with zolmitriptan nasal spray were significantly higher among patients receiving zolmitriptan nasal spray at all doses, compared with placebo (see Table 3).

Table 3: First Attack Data: Percentage of Adult Patients with Headache Response to Zolmitriptan Nasal Spray (Mild or No Headache) 2 Hours Following Treatment in Study 1

PLACEBO (N=218)	Zolmitriptan 2.5 mg (N=219)	Zolmitriptan 5 mg (N=228)
31%	55%*	69%*

*p < 0.001 in comparison with placebo

The estimated probability of achieving an initial headache response following treatment with zolmitriptan nasal spray is depicted in Figure 1.

Figure 1: Estimated probability of achieving an initial headache response after treatment in Study 1

Note: Figure 1 shows the Kaplan-Meier plot of the probability over time of obtaining headache response (moderate or severe headache improving to mild or no pain) following treatment with zolmitriptan nasal spray. The estimates displayed are based on a placebo controlled, outpatient trial providing evidence of efficacy. Patients not achieving headache response or taking additional treatment prior to 4 hours were censored to 4 hours.

For patients with migraine associated photophobia, phonophobia, and nausea at baseline, there was a decreased incidence of these symptoms following administration of zolmitriptan nasal spray as compared with placebo.

Four to 24 hours following the initial dose of study treatment, patients were allowed to use additional treatment for pain relief in the form of a second dose of study treatment or other medication. The estimated probability of patients taking a second dose or other medication for migraine over the 24 hours following the initial dose of study treatment is summarized in Figure 2.

Figure 2: Estimated probability of patients taking an escape medication within the 24 hours following the initial dose of study treatment in Study 1

*This Kaplan-Meier plot is based on data obtained from the placebo controlled clinical trial. Patients not using additional treatments were censored at 24 hours. The plot includes both patients who had headache response at 2 hours and those who had no response to the initial dose. It should be noted that the protocol did not allow remedication within 4 hours post dose.

The efficacy of zolmitriptan was unaffected by presence of aura; presence of headache upon awakening, relationship to menses; gender, age or weight of the patient; or presence of pre-treatment nausea.

The efficacy of zolmitriptan nasal spray 5 mg was further supported by an interim analysis of another similarly designed trial. The 2-hour headache response rates for the first 210 subjects in that study for zolmitriptan 5 mg and placebo were 70% and 47%, respectively (N=108 and 102, respectively, p=0.0006).

14.2 Pediatric Patients 12 to 17 Years of Age

The efficacy of zolmitriptan nasal spray in the acute treatment of migraine headache with or without aura in pediatrics patients 12 to 17 years of age was demonstrated in Study 2, a randomized, double-blind, placebo-controlled trial with a single-blind run-in period.

Patients had to have an established diagnosis of migraine (history indicating the presence of migraine for at least 1 year) with or without aura with a typical untreated migraine headache attack lasting 3 hours or more. The study included treatment of a single migraine headache attack with 1 dose of single-blind placebo during the 30-day run-in period. If the patient met all conditions for randomization, including a lack of response to the placebo run-in, a subsequent single migraine headache attack was treated with 1 blinded dose of either zolmitriptan nasal spray 5 mg, 2.5 mg, or matching placebo.

In Study 2, of the patients taking zolmitriptan nasal spray 2.5 mg or 5 mg, 62% were female and 93% were Caucasian, with a mean age of 14 years (range 12 to 17 years).

Study 2 evaluated the proportion of pediatric patients 12 to 17 years of age who had no headache pain at 2 hours following treatment. Headache response (defined as a reduction in migraine-related headache pain severity from moderate or severe pain to mild or no pain) and the absence of nausea, photophobia, and phonophobia at 2 hours post treatment were also assessed. As shown in Table 4, the percentage of pediatric patients 12 to 17 years of age with no headache pain at 2 hours following treatment was significantly higher for zolmitriptan nasal spray 5 mg than placebo.

Table 4: Percentage of Pediatric Patients 12 to 17 Years of Age with No Headache Pain, With Headache Response, No Nausea, No Photophobia, and No Phonophobia Two Hours after Treatment in Study 2

Two Hours Following Treatment
	Placebo (N=253)	Zolmitriptan 2.5 mg (N=81)	Zolmitriptan 5 mg (N=229)
No Headache Pain	17%	25%	30%*
With Headache Response	39%	53%*	51%*
No Photophobia	44%	66%*	56%*
No Phonophobia	48%	61%*	58%*
No Nausea	66%	70%	72%

*p < 0.05 in comparison with placebo

Two to 24 hours following the initial dose of study treatment, patients were allowed to use their usual medication for pain relief. The estimated probability of patients taking escape medication during the first 24 hours following the initial dose of study treatment is summarized in Figure 3.

Figure 3: Estimated Probability of Pediatric Patients 12 to 17 Years of Age Taking an Escape Medication Within the 24 Hours Following the Initial Dose of Study Treatment in Study 2