Turning now to our financial results. I’ll first discuss the results for the full year 2023 before turning to discuss the fourth quarter of 2023. Total revenues for the full year 2023 were $192.6 million, a 24% decrease compared to $254.4 million for the same period in 2022. HETLIOZ net product sales were $100.2 million for the full year 2023 and saw a 37% decrease compared to $159.7 million for the same period in 2022. The at-risk launch of generic versions of HETLIOZ had a significant impact on HETLIOZ performance during 2023. The decrease to net product sales was attributable to a decrease in price net of deductions and a decrease in volume. Our HETLIOZ net product sales for the first quarter of 2023 reflected higher unit sales as compared to recent prior periods and has resulted in a significant increase of inventory stocking at specialty pharmacy customers throughout 2023.
Turning now to Fanapt. Fanapt net product sales of $90.9 million for the full year 2023 reflect a 4% decrease compared to $94.7 million for the same period in 2022. PONVORY net product sales were $1.6 million for the full year 2023. These net product sales reflect the revenue generated during the period between the product acquisition date of December 7th, 2023, and the year-end on December 31st, 2023. For the full year 2023, Vanda recorded net income of $2.5 million compared to net income of $6.3 million for the same period in 2022. Net income for the full year 2023 included an income tax provision of $3.8 million as compared to an income tax provision of $5 million for the same period in 2022. Operating expenses for the full year 2023 were $206.6 million compared to $248.1 million for the same period in 2022.
The $41.5 million decrease was primarily driven by lower R&D expenses, lower SG&A expenses, and lower cost of goods sold. The decrease in R&D expenses was primarily driven by decreases related to our late-stage Fanapt development program, partially offset by increases related to our tradipitant and VHX-896 also referred to as PDA development programs. The decrease in SG&A expenses was primarily driven by lower expenses associated with marketing, sales, and commercial support activities for our commercial products. The lower cost of goods sold is due to lower HETLIOZ net product sales and the decrease in the royalty rate owed to BMS on HETLIOZ net product sales from 10% to 5% effective in December 2022. Vanda’s cash, cash equivalents, and marketable securities referred to as cash as of December 31st, 2023, was $388.3 million representing a decrease of $101.6 million compared to cash as of September 30th, 2023, and a decrease of $78.6 million compared to December 31st, 2022.
The change in cash during both the fourth quarter of 2023 and the full year of 2023 reflect the completed acquisition of PONVORY from Janssen for $100 million. Turning now to our quarterly results. Total revenues for the fourth quarter of 2023 were $45.3 million, a 30% decrease compared to $64.5 million for the fourth quarter of 2022. Total revenues for the fourth quarter of 2023 increased by 17% as compared to $38.8 million in the third quarter of 2023. HETLIOZ net product sales were $21.1 million for the fourth quarter of 2023, a 47% decrease compared to $40.1 million in the fourth quarter of 2022. HETLIOZ net product sales in the fourth quarter increased by 20% as compared to $17.5 million in the third quarter of 2023. The at-risk launch of a generic version of HETLIOZ continued to have a significant impact on HETLIOZ performance during the fourth quarter of 2023.
The decrease in net product sales relative to the fourth quarter of 2022 was attributable to a decrease in volume. Our HETLIOZ net product sales as reported for the first quarter of 2023 reflected higher unit sales as compared to recent prior periods. The higher unit sales during the first quarter of 2023 resulted in a significant increase of inventory stocking at specialty pharmacy customers throughout 2023. HETLIOZ net product sales during the fourth quarter of 2023 reflect lower unit sales as compared to the fourth quarter of 2022, which was partially attributable to the continued reduction of the elevated inventory levels at specialty pharmacy customers from the end of the first quarter of 2023. Turning now to Fanapt. Fanapt net product sales were $22.6 million for the fourth quarter of 2023, a 7% decrease compared to $24.4 million in the fourth quarter of 2022.
Fanapt net product sales in the fourth quarter of 2023 increased by 6% as compared to $21.3 million in the third quarter of 2023. Fanapt prescriptions in the fourth quarter of 2023 as reported by IQVIA Xponent, decreased by approximately 3% compared to the third quarter of 2023. PONVORY net product sales were $1.6 million for the fourth quarter of 2023. Again, these net product sales reflect the revenue generated during the period between the product acquisition date of December 7, 2023, and year-end on December 31, 2023. For the fourth quarter of 2023, Vanda recorded net loss of $2.4 million compared to net income of $6.9 million for the fourth quarter of 2022 and net income of $100,000 in the third quarter of 2023. The net loss for the fourth quarter of 2023 included an income tax provision of $0.7 million as compared to an income tax provision of $2.8 million for the same period in 2022.
And an income tax benefit of $0.3 million in the third quarter of 2023. Operating expenses in the fourth quarter of 2023 were $52.4 million compared to $57.9 million in the fourth quarter of 2022. The $5.5 million decrease was primarily driven by lower SG&A expenses related to spending on sales activities for our commercial products and legal expenses and lower cost of goods sold due to lower HETLIOZ net product sales and the decrease in the royalty rate owed to BMS on HETLIOZ net product sales from 10% to 5% effective in December 2022., partially offset by higher R&D expenses related to our tradipitant program, including the NDA filing fee and the milestone payment made upon acceptance of the NDA for filing and manufacturing expenses associated with our VHX-896 program.
Operating expenses in the fourth quarter of 2023 increased by $7.6 million as compared to $44.8 million in the third quarter of 2023. This increase was primarily driven by one-time expenses, including $2.4 million of expense recorded for the tradipitant NDA filing fee, $2 million for the associated NDA milestone payment to Eli Lilly, and $3 million of VHX-896 manufacturing costs. Given uncertainty surrounding the US market for HETLIOZ for the treatment of non-24 as a result of the ongoing HETLIOZ patent litigation and the at-risk launch of generic versions of HETLIOZ, Vanda is unable to provide 2024 financial guidance at this time. Vanda will continue to evaluate its ability to provide financial guidance in future periods. HETLIOZ net product sales will likely decline in future periods potentially significantly related to the at-risk launch of generic versions of HETLIOZ in the US.
Additionally, the company constrained HETLIOZ net product sales for the full year 2023 to an amount not probable of significant revenue reversal. As a result, Helios net product sales could experience variability in future periods as the remaining uncertainties associated with variable consideration are resolved. With that, I’ll now turn the call back to Mihael.
Mihael Polymeropoulos: Thank you very much, Kevin. At this point, we will be happy to answer any questions you may have.
Operator: [Operator Instructions] And your question comes from Andrew Tsai with Jefferies. Your line is open.
Andrew Tsai: Hey, good afternoon. Thanks for taking my questions, and big congratulations on the acquisition of PONVORY. So maybe a couple of questions on that asset. First, what do you guys think you can do that J&J might not have been able to do in terms of driving sales growth at PONVORY? And then secondly, why is this differentiated from the other multiple sclerosis drugs out there? What’s the appeal here?
Mihael Polymeropoulos: Thank you very much, Andrew. First of all, to give a background here for everyone. PONVORY ponesimod belongs in the class of sphingosine-1-phosphate receptor analogs. And their mechanism of action is by sequestering or preventing the egress of lymphocytes from peripheral lymph nodes, so that they can have wide applications in disorders where you have autoimmune attack on a system or organ of the body, in the case of multiple sclerosis, this central nervous system. As you also know, this class of drugs has several members. It started some years ago with Fingolimod or Gilenya, now generic and has expanded with additional members in the class. We believe that ponesimod due to its receptor specificity and quick reversibility of effect can play a critical role for the treatment of multiple sclerosis for many groups of patients, especially for those that require a specificity avoiding side effects and quick reversibility.
It has been clear that this drug may be attractive, especially to women of childbearing aids as they contemplate family planning and that the drug will come out of the circulation within a short period of time in a matter of days. And the same is true about the recovery of the lymphocytes. So directly to your question, the increased specificity and quick reversibility both in amount and lymphocyte counts make this drug differentiated and attractive. Second part of your question was what can we do different from J&J. And the simple answer is we plan to market it. J&J for their own business reasons had decided to remove their market in support of the product, while they were in the process of identifying a potent partner to divest it to. And so we believe there is a significant opportunity both with neurologists and multiple sclerosis centers and consumers to be able to increase the awareness of the existence of this potentially quite useful product.
