Michael McDonnell
Executive Vice President and Chief Financial Officer at Biogen
Thank you, Priya and good morning, everyone. I'll provide some highlights and color regarding our financial performance for the second quarter and all of the financial comparisons that you will hear are versus the second quarter of 2022. Total revenue for the second quarter was $2.5 billion, that's a decrease of 5% at actual currency and 3% at constant currency. Non-GAAP diluted earnings per share in the second quarter was $4.02. Total MS Products revenue was $1.2 billion, that's a decrease of 15% at actual currency and 14% at constant currency. So a few recent updates to the MS business this quarter.
First, the decline in MS in the second quarter was attributable to generic entrants for TECFIDERA and broad competition in the MS Market. We did not see much in the way of channel dynamics during the second quarter. Second, as we did announce previously, TECFIDERA's regulatory market protection in the EU was extended by one additional year until February 2nd of 2025. Some of the TECFIDERA generics have not yet fully exited some of the EU markets and some generic products remain in the channel.
The pace of generic withdrawal has been slower than we expected and we're closely monitoring the situation and working to enforce our legal right to market protection. Regarding TYSABRI, we have previously said that there may be a TYSABRI biosimilar launch in the US and EU sometime later in 2023. We are aware of the positive CHMP opinion for the TYSABRI biosimilar in the EU last week. And while we have not seen any biosimilar launches so far, we could see an approval and launch in the coming months.
Moving on now to SMA, global SPINRAZA revenue of $437 million increased 1% at actual currency and 5% at constant-currency. SPINRAZA growth in the U.S. was 12% and that was driven by patient growth. We were encouraged by the performance this past quarter and believe we are making good progress against our goal of returning SPINRAZA to consistent growth. Also as Priya mentioned, we are continuing to generate data to support the efficacy profile of SPINRAZA and we believe that this along with the expected overall market expansion should help enable continued improved performance for SPINRAZA. Biosimilars revenue of $195 million was flat at actual currency and increased 4% at constant currency.
We are continuing to manage supply constraints for IMRALDI and BENEPALI and are monitoring this situation very closely. We've referenced previously that we are evaluating whether this business could create more value outside of Biogen and we are engaged with multiple interested parties and will provide further updates on that process as appropriate.
Alzheimer's disease revenue which includes revenue from ADUHELM and the LEQEMBI collaboration equated to a headwind of $20 million to revenue during the second quarter. As a reminder, LEQEMBI revenue represents our 50% of in market revenue less 50% of commercialization expenses. We expect this line to continue to be negative in 2023 as the ramping of LEQEMBI commercialization expenses will exceed initial revenue.
Total anti-CD20 revenue of $433 million was down 1% and included a $12 million operating loss related to LUNSUMIO. As a reminder, starting this quarter, our pre-tax profit share on RITUXAN, GAZYVA and LUNSUMIO decreased from 37.5% to 35% and that's due to the achievement of certain sales targets for GAZYVA as part of our contractual agreement with Genentech. Contract manufacturing, royalty and other revenue of $198 million was notably higher year-over-year and that was driven mainly by the timing of batches.
Couple of details regarding Q2 expenses, for the second quarter non-GAAP cost of sales was 24% of total revenue and that includes $34 million of idle capacity charges. We continue to see higher cost of sales as a percentage of revenue as a result of product mix and idle capacity charges and in particular the increases that we are seeing in contract manufacturing revenue increases our overall cost of sales as a percentage of revenue.
So in terms of modeling for the remainder of 2023, I'd offer that we believe contract manufacturing revenue will remain strong and will contribute to a higher-cost of sales as a percentage of revenue for the remainder of this year as compared to the 24.1% that we saw in the second quarter. Second quarter non-GAAP R&D expense includes roughly $13 million in estimated study closeout costs, related to BIIB093.
As Priya mentioned, we're now substantially complete with our R&D prioritization. We estimate that this will result in gross savings of approximately $250 million next year, though this will be partially offset by natural increases in R&D due to portfolio progression. The decrease in second quarter SG&A expense was attributed to roughly $70 million of savings initiatives and that was partially offset by approximately $35 million of reinvestments, mostly related to launch costs.
We continue to expect our operating expenses to be lower in the second half of the year than in the first half as we complete the run-rate savings from our previously announced cost initiatives, as well as a modest impact from our new Fit-for-Growth initiative.
So now I'd like to take a minute to provide a little bit of additional detail on our new Fit-for-Growth program. This program will include changes to our operating model of a significant reduction of certain centralized functions. A substantial portion of the $700 million of net annual opex savings are expected to come from a net headcount reduction of approximately 1,000, which we expect to rightsize the company with our business plan and enable us to return to sustainable growth. I would reiterate that the opex savings shown here are on an annualized basis. We believe that this is an efficient program with 70% of our expected gross opex savings to be realized as net savings.
All-in, we expect a very modest impact on 2023 expenses and believe the net opex savings will be split roughly equally between 2024 and 2025 and all of these savings are incremental to any previously announced cost reduction progress. A few quick comments on our balance sheet, including the approximately $813 million that we received during the quarter related to the sale of our equity stake in Samsung Bioepis, we ended the quarter with $7.3 billion in cash and marketable securities.
On June 30th, we had $6.3 billion in debt and that puts us in a net cash position of roughly $1 billion. We continue to generate steady, positive cash flow from operations with free cash flow of $416 million during the second quarter.
And finally, now let me turn to our financial guidance for full-year 2023. The business remains on-track with our forecast for the full-year and today we are reaffirming our full-year guidance of a full-year 2023 revenue decline in the mid single-digit percentage range as compared to 2022 reported results and full-year 2023 non-GAAP diluted earnings per share of between $15 and $16 and you can refer to our press release for other important guidance assumptions.
So now, I'll turn it back over to Chris for a few closing comments.