Revenue
Revenue from product development and licensing agreements for the nine months ended September 30, 2024 was relatively consistent with the nine months ended September 30, 2023. The $3.1 million increase in contracts and grants revenue for the nine months ended September 30, 2024, as compared to the nine months ended September 30, 2023, was primarily due to an increase in revenue from our contract manufacturing and research and development agreements with Rockefeller University.
Research and Development Expense
Research and development expenses consist primarily of (i) personnel expenses, (ii) laboratory supply expenses relating to the development of our technology, (iii) facility expenses and (iv) product development expenses associated with our drug candidates as follows:
| | | | | | | | | | | | |
| | Nine Months Ended | | Increase/ | |
| | September 30, | | (Decrease) | |
| | 2024 | | 2023 | | $ | | % | |
|
| | (In thousands) | |
Personnel | | $ | 37,176 | | $ | 28,559 | | $ | 8,617 | | 30 | % |
Laboratory supplies | | | 3,997 | | | 4,167 | | | (170) | | (4) | % |
Facility | | | 3,799 | | | 3,699 | | | 100 | | 3 | % |
Product development | | | 64,732 | | | 45,348 | | | 19,384 | | 43 | % |
Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $8.6 million increase in personnel expenses for the nine months ended September 30, 2024, as compared to the nine months ended September 30, 2023, was primarily due to higher stock-based compensation expense and an increase in employee headcount.
Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. Laboratory supply expenses for the nine months ended September 30, 2024 were relatively consistent with the nine months ended September 30, 2023.
Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. Facility expenses for the nine months ended September 30, 2024 were relatively consistent with the nine months ended September 30, 2023.
Product development expenses include clinical investigator site fees, external trial monitoring costs, data accumulation costs, contracted research and outside clinical drug product manufacturing. The $19.4 million increase in product development expenses for the nine months ended September 30, 2024, as compared to the nine months ended September 30, 2023, was primarily due to an increase in barzolvolimab clinical trial expenses, partially offset by a decrease in barzolvolimab contract manufacturing expenses.
General and Administrative Expense
The $6.2 million increase in general and administrative expenses for the nine months ended September 30, 2024, as compared to the nine months ended September 30, 2023, was primarily due to higher stock-based compensation and barzolvolimab commercial planning expenses.
Investment and Other Income, Net
The $19.5 million increase in investment and other income, net for the nine months ended September 30, 2024, as compared to the nine months ended September 30, 2023, was primarily due to higher levels of cash as a result of our November 2023 and March 2024 underwritten public offerings.