Gross profit for the third quarter of 2019 was $45.1 million or 70% of net revenue, compared to $31.3 million, or 62% of net revenue for the third quarter of 2018, an increase of $13.8 million, or 44%. The improvement in gross profit and gross profit margin percentage resulted primarily from a more favorable product mix of revenue in the third quarter of 2019, PuraPly regaining pass-through reimbursement status, and volume-based manufacturing efficiencies.
Operating expenses for the third quarter of 2019 were $53.4 million, compared to $41.4 million for the third quarter of 2018, an increase of $12.0 million, or 29%. The increase in operating expenses in the third quarter of 2019 as compared to the third quarter of 2018 was driven primarily by higher selling, general and administrative expenses which increased to $49.5 million, compared to $38.6 million in the third quarter of 2018, an increase of $10.9 million, or 28%. The increase in selling, general and administrative expenses is primarily due to additional headcount, predominantly in the direct sales force, increased sales commissions due to higher sales, and increased marketing and promotional expenses for the Company’s products. R&D expense was $3.9 million for the third quarter of 2019, compared to $2.8 million in the third quarter of 2018, an increase of $1.1 million, or 41%. The increase in R&D was driven by additional headcount and continued and new investments in clinical programs and our new product pipeline.
Operating loss for the third quarter of 2019 was $8.3 million, compared to an operating loss of $10.1 million for the third quarter of 2018, a decrease of $1.8 million, or 18%. Total other expenses, net, for the third quarter of 2019 were $2.4 million, compared to $3.0 million for the third quarter of 2018, a decrease of $0.6 million, or 19%. The decrease was driven primarily by a decrease in interest expense and a decrease in the change in the fair value of warrant liability.
Net loss for the third quarter of 2019 was $10.7 million, or $0.12 per share, compared to a net loss of $13.1 million, or $0.19 per share, for the third quarter of 2018, a decrease of $2.3 million, or 18%.
As of September 30, 2019, the Company had $23.0 million in cash and $100.8 million in debt obligations, of which $17.8 million were capital lease obligations, compared to $21.3 million in cash and $59.3 million in debt obligations, of which $17.7 million were capital lease obligations, as of December 31, 2018.
First Nine Months of 2019 Results:
Net revenue for the nine months ended September 30, 2019 was $186.3 million, compared to $129.9 million for the first nine months of 2018, an increase of $56.5 million, or 44%. The increase in net revenue was driven by a $47.7 million increase, or 43%, in net revenue of Advanced Wound Care products and a $8.8 million increase, or 44%, in net revenue of Surgical & Sports Medicine products compared to the prior year. Net revenue of PuraPly products for the nine months ended September 30, 2019 were $86.9 million, compared to $41.3 million for the first nine months of 2018, an increase of $45.6 million, or 111%. Net revenue of PuraPly products represented approximately 47% of net revenue for the nine months ended September 30, 2019, compared to 32% for the first nine months of 2018.
Gross profit for the nine months ended September 30, 2019 was $130.8 million or 70% of net revenue, compared to $78.6 million, or 60% of net revenue, for the first nine months of 2018, an increase of $52.2 million, or 66%. The largest contributors to the increase in gross margin from the year earlier period were increased sales volume due to the strength in our Advanced Wound Care products, the resulting higher margins realized as a result of manufacturing efficiencies, and PuraPly regaining pass-through reimbursement status for the2-year period effective October 1, 2018.