Sumatriptan (Page 5 of 7)

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

In carcinogenicity studies in mouse and rat, sumatriptan was administered orally for 78 and 104 weeks, respectively, at doses up to 160 mg/kg/day (the high dose in rat was reduced from 360 mg/kg/day during Week 21). There was no evidence in either species of an increase in tumors related to sumatriptan administration. Plasma exposures (AUC) at the highest doses tested were 20 and 8 times that in humans at the maximum recommended human dose (MRHD) of 200 mg/day.

Mutagenesis

Sumatriptan was negative in in vitro (bacterial reverse mutation [Ames], gene cell mutation in Chinese hamster V79/HGPRT, chromosomal aberration in human lymphocytes) and in vivo (rat micronucleus) assays.

Impairment of Fertility

When sumatriptan (5, 50, 500 mg/kg/day) was administered orally to male and female rats prior to and throughout the mating period, there was a treatment-related decrease in fertility secondary to a decrease in mating in animals treated with doses greater than 5 mg/kg/day (less than the MRHD on a mg/m2 basis). It is not clear whether this finding was due to an effect on males or females or both.

When sumatriptan was administered by subcutaneous injection to male and female rats prior to and throughout the mating period, there was no evidence of impaired fertility at doses up to 60 mg/kg/day.

13.2 Animal Toxicology and/or Pharmacology

Corneal Opacities

Dogs receiving oral sumatriptan developed corneal opacities and defects in the corneal epithelium. Corneal opacities were seen at the lowest dose tested, 2 mg/kg/day, and were present after 1 month of treatment. Defects in the corneal epithelium were noted in a 60 week study. Earlier examinations for these toxicities were not conducted and no‑effect doses were not established. Plasma exposure at the lowest dose tested was approximately 2 times that in humans at the MRHD.

14 CLINICAL STUDIES

The efficacy of sumatriptan tablets in the acute treatment of migraine headaches was demonstrated in 3 randomized, double-blind, placebo-controlled trials. Patients enrolled in these 3 trials were predominately female (87%) and Caucasian (97%), with a mean age of 40 years (range: 18 to 65 years). 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 up to 4 hours after dosing. Associated symptoms such as nausea, photophobia, and phonophobia were also assessed. Maintenance of response was assessed for up to 24 hours postdose. A second dose of sumatriptan tablets or other medication was allowed 4 to 24 hours after the initial treatment for recurrent headache. Acetaminophen was offered to patients in Trials 2 and 3 beginning at 2 hours after initial treatment if the migraine pain had not improved or had worsened. Additional medications were allowed 4 to 24 hours after the initial treatment for recurrent headache or as rescue in all 3 trials. The frequency and time to use of these additional treatments were also determined. In all trials, doses of 25, 50, and 100 mg were compared with placebo in the treatment of migraine attacks. In 1 trial, doses of 25, 50, and 100 mg were also compared with each other.

In all 3 trials, the percentage of patients achieving headache response 2 and 4 hours after treatment was significantly greater among patients receiving sumatriptan tablets at all doses compared with those who received placebo. In 1 of the 3 trials, there was a statistically significant greater percentage of patients with headache response at 2 and 4 hours in the 50 mg or 100 mg group when compared with the 25 mg dose groups. There were no statistically significant differences between the 50 mg and 100 mg dose groups in any trial. The results from the 3 controlled clinical trials are summarized in Table 2.

Table 2. Percentage of Patients with Headache Response (Mild or No Headache) 2 and 4 Hours following Treatment
Sumatriptan Tablets 25 mg Sumatriptan Tablets 50 mg Sumatriptan Tablets 100 mg Placebo
2 h 4 h 2 h 4 h 2 h 4 h 2 h 4 h
Trial 1 52% a (n = 298) 67% a 61% a,b (n = 296) 78% a,b 62% a,b (n = 296) 79% a,b 27% (n = 94) 38%
Trial 2 52% a (n = 66) 70% a 50% a (n = 62) 68% a 56% a (n = 66) 71% a 26% (n = 65) 38%
Trial 3 52% a (n = 48) 65% a 54% a (n = 46) 72% a 57% a (n = 46) 78% a 17% (n = 47) 19%

a P<0.05 in comparison with placebo.

b P<0.05 in comparison with 25 mg.

The estimated probability of achieving an initial headache response over the 4 hours following treatment in pooled Trials 1, 2, and 3 is depicted in Figure 1.

Figure 1. Estimated Probability of Achieving Initial Headache Response within 4 Hours of Treatment in Pooled Trials 1, 2, and 3a

Figure 1
(click image for full-size original)

a The figure shows the probability over time of obtaining headache response (no or mild pain) following treatment with oral sumatriptan. The averages displayed are based on pooled data from the 3 clinical controlled trials providing evidence of efficacy. Kaplan-Meier plot with patients not achieving response and/or taking rescue within 240 minutes censored to 240 minutes.

For patients with migraine-associated nausea, photophobia, and/or phonophobia at baseline, there was a lower incidence of these symptoms at 2 hours (Trial 1) and at 4 hours (Trials 1, 2, and 3) following administration of sumatriptan tablets compared with placebo.

As early as 2 hours in Trials 2 and 3, or as early as 4 hours in Trial 1, through 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. The Estimated Probability of Patients Taking a Second Dose of Sumatriptan Tablets or Other Medication to Treat Migraine over the 24 Hours following the Initial Dose of Study Treatment in Pooled Trials 1, 2, and 3a

a Kaplan-Meier plot based on data obtained in the 3 clinical controlled trials providing evidence of efficacy with patients not using additional treatments censored to 24 hours. Plot also includes patients who had no response to the initial dose. No remedication was allowed within 2 hours postdose.

There is evidence that doses above 50 mg do not provide a greater effect than 50 mg. There was no evidence to suggest that treatment with sumatriptan tablets was associated with an increase in the severity of recurrent headaches. The efficacy of sumatriptan tablets was unaffected by presence of aura; duration of headache prior to treatment; gender, age, or weight of the subject; relationship to menses; or concomitant use of common migraine prophylactic drugs (e.g., beta-blockers, calcium channel blockers, tricyclic antidepressants). There were insufficient data to assess the impact of race on efficacy.

Figure 2
(click image for full-size original)

16 HOW SUPPLIED/STORAGE AND HANDLING

Sumatriptan Tablets USP, 25 mg, 50 mg, and 100 mg of sumatriptan (base) as the succinate.

Sumatriptan Tablets USP, 25 mg are yellow colored, film coated, triangular biconvex debossed with “S” on one side and “102” on the other side, supplied in Unit dose packs -Carton of 9 Unit-dose tablets (1 x 9s) each with cross perforation and individually labeled. NDC 42043-220-09

Sumatriptan Tablets USP, 50 mg are pink colored, film coated, triangular biconvex debossed with “S” on one side and “103” on the other side, supplied in Unit dose packs -Carton of 9 Unit-dose tablets (1 x 9s) each with cross perforation and individually labeled. NDC 42043-221-09

Sumatriptan Tablets USP, 100 mg are white to off white, film coated, triangular biconvex debossed with “S” on one side and “104” on the other side, supplied in Unit dose packs -Carton of 9 Unit-dose tablets (1 x 9s) each with cross perforation and individually labeled. NDC 42043-222-09

Store at 20° to 25°C (68° and 77°F). [see USP Controlled Room Temperature].

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