General and Administrative
General and administrative expenses increased by $0.9 million, or 29.8% for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. The primary contributor was an increase of $0.8 million in personnel-related costs and consulting fees for general and administrative expenses.
General and administrative expenses increased by $1.9 million, or 33.8% for the six months ended June 30, 2022 compared to the six months ended June 30, 2021. The primary contributor was an increase of $1.7 million in personnel-related costs and consulting fees for general and administrative expenses.
Commercial
For the three months ended June 30, 2022, commercial expenses increased by $0.4 million, or 21.1%, compared to the three months ended June 30, 2021. The increase is due to consulting and marketing analytics.
Commercial expenses increased by $0.7 million, or 20.5%, for the six months ended June 30, 2022, compared the same period in 2021. The increase is due to personnel related costs.
Starting approximately six months to one year before we file our new drug application, or NDA with the FDA, we anticipate our commercial expenses will increase substantially as we invest in the infrastructure, personnel and operational expenses required to launch our first product in the United States, if approved.
Interest Income, net
Interest income, net, was $0.2 million and $0.1 million for the three months ended June 30, 2022 and 2021, respectively. Interest income, net of bank charges, was $0.2 million and $0.1 million for the six-month periods ended June 30, 2021 and 2020, respectively. The increase in interest income was due to higher interest rates earned on investments in 2022 when compared to 2021.
Liquidity and Capital Resources
Sources of Liquidity
We have incurred operating losses and experienced negative operating cash flows since our inception, and we anticipate continuing to incur losses for at least the next several years. As of June 30, 2022, we had cash, cash equivalents and short-term investments of $86.2 million and an accumulated deficit of $237.0 million.
We have evaluated whether material uncertainties exist relating to clinical trials, the COVID-19 pandemic and the impact on market conditions. The COVID-19 pandemic has had an impact on our business, operations and clinical development timelines. Government orders and restrictions in order to control the spread of the disease have impacted patient recruitment, enrollment and follow-up visits at clinical sites. At the date of the publication of our quarterly report on form 10-Q, it is not possible to reliably estimate the length and severity of these developments. We expect that our current operating plan, existing cash and cash equivalents and access to financing sources to be sufficient to fund our operations and determined that there are no events or conditions that may cast substantial doubt on our ability to continue as a going concern for at least the next 12 months from the date of this filing. Based on our cash and cash equivalents as of June 30, 2022, we expect to be able to support our ongoing operations into second-half of 2023.
Funding Requirements
We use our cash primarily to fund research and development expenditures. We expect our total research and development expenses to increase as we continue the development of etripamil and prepare to pursue regulatory approval. We expect to incur an increase in general and administrative expenses, and a continued increase in expenses related to commercial activities in 2022 as we focus our efforts on the clinical pathway and potential commercialization of etripamil. We expect to incur increasing operating losses for the foreseeable future as we continue the clinical development of our product