Combating Coronavirus: Key Role of Cyclodextrins in Treatment and Prevention

Background

A new strain of coronavirus (2019-nCoV) started to emerge in late December 2019 from Wuhan, the capital of Hubei Province in central China, which is a city with a population of 11 million. The pneumonialike illness, which has spread rapidly since first appearing in late December 2019, was declared a ‘public health emergency’ by the World Health Organization. As of 10 Feb 2020, the virus has infected over 40,000 people in China, over 300 in other countries, and killed more than 900 people. According to the US CDC, “person-to-person spread is thought to occur mainly via respiratory droplets produced when an infected person coughs or sneezes, similar to how influenza and other respiratory pathogens spread. These droplets can land in the mouths or noses of people who are nearby or can possibly be inhaled into the lungs.” At the molecular level, the sequence analysis and high sequence similarity of 2019-nCoV to that of SARS-CoV suggests that angiotensin-converting enzyme 2 (ACE2) is the receptor for entry into human cells. 1 Roquette is committed to helping patients in need. Roquette has extensive experience and a long history of supplying KLEPTOSE® hydroxypropyl beta-cyclodextrins (HPβCD) as a functional excipient and a specialty active pharmaceutical ingredient (API). It is approved for oral and parenteral administration in humans by the EU, US, and Chinese regulatory authorities. In this short communication, we will review treatment strategies and the potential role of cyclodextrins in combating the illness as an excipient, adjuvant and potentially an API.

Antivirals

Combinations of antivirals have been repurposed to treat 2019-nCoV and have shown positive results. However, the development of antiviral drugs can be hampered by formulation challenges, most notably poor aqueous solubility of the active compound.2 Adequate drug solubility is imperative to ensure bioavailability and consequently, the efficacy of oral antiviral treatments. In the case of parenteral therapy, which offers the benefit of rapid onset in critically-ill patients, drug solubility is even more critical, given that intravenous solutions must be particulate-free and buffered to physiological pH. Table 1 shows antiviral drugs currently being tested or in development to treat 2019-nCoV. Cyclodextrin drug delivery systems can effectively overcome formulation challenges of antiviral drugs by offering improved solubility and bioavailability. HPβCD is cited in the FDA’s list of Inactive Pharmaceutical Ingredients, and is approved for use in oral and parenteral formulations due to its high aqueous solubility and excellent safety profile even at relatively high doses.3

Vaccines

Accelerated measures are being taken by companies and institutions to develop vaccines against 2019- nCoV infection as there are currently no approved vaccines. Since the release of the 2019-nCoV genetic sequence in early January 2020, scientists have been working around the clock to produce stable versions of the vaccines mainly based on non-living subunit vaccine and mRNA vaccine technologies. Companies including Johnson & Johnson,7 Clover Pharmaceuticals,8 and Novavax9 are developing virus subunit vaccines.Other companies like Moderna and CureVac are developing messenger RNA-based vaccines.10,11 Non-living vaccine antigens, especially subunit vaccines, are poorly immunogenic and require additional adjuvant components to stimulate immunity. Finding an adjuvant to stimulate efficient, long-lasting and safe immune response is challenging. As an adjuvant, HPβCD induces Type 2 T-helper (Th2) cell response, enhances antigen (vaccine)-specific antibody titers, and maintains longer immune response. Moreover, unlike commonly used adjuvants in human vaccine, such as aluminum salt, HPβCD induces little Immunoglobulin E (IgE) production, which is a risk factor affecting the allergenic potential of vaccines.12,13 HPβCD can act as a safe and efficient adjuvant in developing successful vaccinesfor 2019-nCoV prevention. Daiichi Sankyo is conducting a Phase I clinical trial in Japan for their HPβCD adjuvanted influenza split vaccine.14

Modified Cyclodextrin with Virucidal Activity

Modified beta-cyclodextrin can be rendered with antiviral activities. For example, to mimic heparin sulfates, which is a broad-spectrum antiviral agent but inefficient when diluted, β-cyclodextrin is modified with mercaptoundecane sulfonic acid. The new functional molecules are broad-spectrum, biocompatible, and virucidal at micromolar concentrations in vitro and in vivo (mouse model) against many viruses.21 Due to its safety, biocompatibility, and unique structure, cyclodextrins can be modified to provide nontoxic virucidal action.

Conclusion

The 2019-nCoV is spreading rapidly across the globe and effective treatments are in urgent need.
Companies are accelerating their drug development to combat 2019-nCoV infection; nevertheless,
formulation development for any drug candidate is critical and challenging. HPβCD can effectively act as
a safe, enabling excipient for solubility enhancement of antiviral drugs, stability improvement of
therapeutic monoclonal antibodies, and as a vaccine adjuvant. Cyclodextrins can potentially be used for
infection containment or as virucidal agents after structural modification.

For more information on how Roquette can share its expertise on HPβCD with your specific formulation,
please contact WEN-CHIN.FOO@roquette.com.

To order samples of KLEPTOSE® HPBCD, please visit:

https://www.roquette.com/product-finder-pharma-and-nutraceuticals/family/cyclodextrins