Cycle 3 Data Shows Continued Efficacy for SGX301 in Phase 3 CTCL Trial
On October 22, 2020, Soligenix, Inc. (NASDAQ:SNGX) announced data from Cycle 3 of the Phase 3 FLASH clinical trial of SGX301 in cutaneous T cell lymphoma (CTCL) shows continued efficacy for the product along with being safe and well tolerated. The FLASH (Fluorescent Light Activated Synthetic Hypericin) trial was a randomized, double blind, placebo controlled study that enrolled 169 patients with either Stage IA, IB, or IIA mycosis fungoides (the most common type of CTCL) (NCT02448381). In Cycle 1, patients were randomized 2:1 (n=116 for SGX301; n=50 for placebo) to receive twice weekly treatment of either 0.25% SGX301 or placebo (an ointment with the same light exposure as for SGX301) for six weeks, with treatment response determined at the end of the eighth week. In Cycle 2, a total of 155 patients received 0.25% SGX301 on their target lesions (110 receiving 12 weeks of SGX301 and 45 receiving six weeks of placebo treatment followed by six weeks of SGX301 treatment), and for those that decided to continue in the trial there was a third treatment cycle where 0.25% SGX301 was applied to all of the patient’s lesions.
Response rates further improved in Cycle 3 with 49% of patients electing to receive SGX301 for 18 weeks demonstrating a 50% or greater reduction in the combined CAILS (Composite Assessment of Index Lesion Score). This compares to 40% of patients demonstrating a similar reduction after completing 12 weeks of treatment (P=0.046). The company had previously reported a statistically significant treatment response in the CAILS primary endpoint assessed at 8 weeks for Cycle 1 with 16% of patients receiving SGX301 responding compared to only 4% receiving placebo responding (P=0.04). We are very encouraged by the robust increased response to treatment over time.
Continued analysis of Cycle 1 and 2 data shows that following 12 weeks of treatment with SGX301, there is a similar response on both patch (37% response; P=0.0009) and plaque (42% response; P<0.001) lesions when compared to Cycle 1 placebo lesion responses. This is likely due to the wavelength of light used for SGX301, which penetrates deeper into the skin compared to UV light, as shown in the following image. In addition, the ability of SGX301 to be effective against harder to treat plaque lesions could have positive implications for its potential use in treating psoriasis.
The important takeaways for investors are that SGX301 is a safe and well tolerated CTCL treatment that shows positive effects in a relatively short period of time and has increasing efficacy with continued use. Since CTCL is a long-lasting condition, safety and tolerability are at the forefront of prescribing physicians concerns when treating patients, and many other CTCL therapies have a number of potential serious side effects, particularly with extended use. We believe the data that Soligenix has compiled for SGX301 in treating CTCL positions it as a promising front-line therapy for a large percentage of patients.
Now that the trial is concluded, the company will turn its attention to identifying a suitable commercialization partner and preparing a New Drug Application, which we anticipate occurring in the first half of 2021.
We remind investors that the company will be announcing Phase 3 clinical data for SGX942 in oral mucositis (OM) before the end of 2020. Thus far, the stock has not responded favorably to the positive data for SGX301 in CTCL, which may indicate that investors are waiting on the OM data. However, we believe the stock is exceptionally undervalued at its current price, even if SGX301 was the only product in development. Our current valuation is $15 and at the current depressed price we view an investment in Soligenix as offering a very positive risk/reward profile.
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