Krystal Biotech, Inc. (Nasdaq: KRYS), a gene therapy company dedicated to developing and commercializing novel treatments for patients suffering from rare dermatological diseases, today announced positive results from its Phase 2 placebo-controlled clinical trial of KB103 (GEM-2) study and an update on results from Phase 1 (GEM-1) study.
GEM-2 Study of KB103
In the Phase 2 trial, four additional patients (two adults (ages 22 and 19) and two pediatric (ages 14 and 15)) with severe generalized recessive dystrophic epidermolysis bullosa ("RDEB") were enrolled in December 2018. Prior to dosing, three wounds of size up to 20cm2were selected on each patient for the trial and subsequently randomized to receive either KB103 or placebo in a 2:1 (KB103: placebo) ratio. A total of four KB103-treated recurring wounds and two KB103-treated chronic wounds were included in the trial results. Having established the presence of type VII collagen (COL7) and anchoring fibrils in the Phase 1 portion of the trial and acknowledged by the FDA, the endpoints of the Phase 2 portion were revised toward a focus on clinical improvement.
One of the four patients (aged 19) voluntarily dropped out of the trial after 30 days due to an inability to travel to the clinical trial site. The dropout was unrelated to any safety or efficacy issues with KB103. Data from this patient was excluded from the overall analysis. The Phase 2 analysis was conducted on remaining three patients (six KB103 treated wounds and three placebo treated wounds) in the Phase 2 trial. With respect to the six KB103 treated wounds on patients enrolled for the duration of the Phase 2 trial, two were categorized as chronic and four as recurring based on patient reporting. Chronic wounds remain open for greater than 12 weeks while recurring wounds open and close spontaneously.
Earlier in the Phase 1 trial, two adult patients with severe generalized RDEB were evaluated. In each patient, two wounds with an approximate surface area of 10 cm2 were randomized to receive either topical KB103 or placebo.
Clinical Data Update
Safety data from all patients in Phase 2 trial at 90 day timepoint show that KB103 was well tolerated. No serious adverse events, and no drug-related adverse events were reported. No inflammation or irritation was observed in KB103-treated wounds. In addition, no antibody response was noted for COL7.
Clinical Endpoint: Percent of Wound Closure
1. Five out of six wounds (four recurring and two chronic) treated with KB103 in the Phase 2 trial closed 100% during the trial.
2. The wound that did not close completely has been reported by the patient to be a chronic deep wound that has remained open for more than four years. It was closed 35% at the 30 day measurement and 42% at the 90 day measurement timepoint. The other chronic wound treated with KB103 in the trial took 41 days to close completely.
3. In the combined Phase 1 and Phase 2 trials, seven out of eight wounds treated with KB103 closed 100%.
4. None of the placebo treated wounds closed fully during the duration of the study to determine time to 100% wound closure. At 90 day timepoint, all three placebo wounds remained fully open.
Clinical Endpoint: Time to 100% wound closure
5. The average time to 100% wound closure on all KB103 treated wounds (five out of six) in the Phase 2 trial was 23.4 days (median 22 days). On the four recurring wounds, the average time to 100% wound closure was 19 days (median 21 days).
6. The average time to 100% wound closure on all KB103 treated wounds (two out of two) in the Phase 1 trial was 12 days (median 12 days).
7. The average time to 100% wound closure on all KB103 treated wounds in the combined Phase 1 and Phase 2 trials (seven out of eight) was 20.14 days (median 20 days).
Clinical Endpoint: Duration of wound closure
8. In Phase 1 trial, the duration of wound closure on two patients following 100% wound closure as of the last follow up was 184 days (6.6 months) and 174 days (6.2 months).
9. The average duration of wound closure at 90 day timepoint in Phase 2 trial on all recurring wounds was 71 days (median 68 days) which is the most up to date measurement available. We will continue to monitor the ongoing duration of wound closure in the Phase 2 trial.
10. The dur...
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