Bernard J. Birkett
Senior Vice President, Chief Financial and Operations Officer at West Pharmaceutical Services
Thank you, Eric, and good morning. Let's review the numbers in more detail. We'll first look at Q3 2024 revenues and profits, where we saw a low single-digit decline in organic sales as well as declines in operating profit and diluted EPS compared to the third quarter of 2023. I will take you through the drivers impacting sales and margin in the quarter as well as some balance sheet takeaways.
And finally, we will provide an update to our 2024 guidance. First up, Q3. Our financial results are summarized on slide seven, and the reconciliation of non-U.S. GAAP measures are described in slide s 16 to 20. We recorded net sales of $746.9 million, representing an organic sales decline of 0.5%. Looking at slide eight. Proprietary Products organic net sales decreased 0.5% in the quarter. High-Value Products, which made up approximately 75% of Proprietary Products sales in the quarter, declined by low single digits primarily due to destocking of our FluroTec, Nova brand and Westar products, offset by an increase in sales of our drug delivery devices.
Looking at the performance of the market units. The pharma market unit saw a mid-single-digit increase driven by an increase in the sales of Nova brand products and administrative systems. The biologics market experienced a low single-digit decline primarily driven by destocking of FluroTec, NovaPure and Westar products, offset by an increase in our drug delivery devices. And the generics market unit declined mid-single digits primarily due to lower volumes in Nova brand products.
Our Contract Manufacturing segment revenue on a constant currency basis was consistent with our performance for the third quarter of last year. Our adjusted operating profit margin of 21.5% was a 270 basis point decrease from the same period last year. Finally, adjusted diluted EPS declined 14.4% for Q3. Excluding stock-based compensation tax benefit, EPS decreased by 10%. Now let's review the drivers in both our revenue and profit performance. On slide nine, we show the contribution to organic sales decline in the quarter. Sales price increases contributed $34.2 million, a 4.6 percentage points of growth in the quarter, as did a foreign currency tailwind of approximately $2.9 million.
Included in sales price is a $19 million customer incentive associated with achieving volume levels. More than offsetting price and FX was a negative volume and mix impact of $37.6 million, primarily due to lower sales volume caused by customer inventory management decisions in the period and a mix shift from HVP components to drug delivery devices based on customer demand. Looking at margin performance. slide 10 shows our consolidated gross profit margin of 35.4% for Q3 2024, down from 38.6% in Q3 2023.
Proprietary Products third quarter gross profit margin of 39.2% was 420 basis points lower than the margin achieved in the third quarter of 2023. The key drivers for the decline in Proprietary Products gross profit margin were lower production volumes in our high-margin HVP components and a mix shift to lower-margin drug delivery devices, which we expect to increase over time with yield improvements from automation.
These margin reductions were partly offset by increased sales price inclusive of the previously mentioned customer incentives. Contract Manufacturing third quarter gross profit margin of 19.9%, was 130 basis points greater than the margin achieved in the third quarter of 2023 primarily due to production efficiencies. Now let's look at our balance sheet and review how we've done in terms of generating cash for the business. On Slide 11, we have listed some key cash flow metrics.
Operating cash flow was $463.3 million for the nine months ended September 2024, a decrease of $74.1 million compared to the same period last year, a 13.8% decrease primarily due to a decline in operating results. For third quarter 2024 year-to-date capital spending was $272.1 million, $18.8 million higher than the same period last year. We continue to leverage our capex to increase both our High-Value Products and Contract Manufacturing capacity.
Working capital of approximately $1.034 billion at September 30, 2024, decreased by $230.5 million from December 31, 2023, primarily due to a reduction in our cash balance. Our cash balance at September 30, 2024, of $490.9 million was $363 million lower than our December 2023 balance. The decrease in cash is primarily due to $506.5 million of share repurchases and our capital expenditures offset by cash from operations. Turning to guidance. Slide 12 provides a high-level summary. We are increasing our full year 2024 net sales guidance to a range of $2.875 billion to $2.905 billion from a prior range of $2.87 billion to $2.9 billion, reflecting the impact of foreign exchange. There is an estimated full year 2024 headwind of approximately $1 million based on current foreign exchange rates.
We expect an organic sales decline of approximately 1.5% to 2%. We are raising our full year 2024 adjusted diluted EPS guidance to be in a range of $6.55 to $6.75 compared to a prior range of $6.35 to $6.65. Also, our capex guidance remains at $375 million, which is unchanged from prior guidance. There are some key elements I want to bring your attention to as you review our guidance. Full year 2024 adjusted diluted EPS guidance range includes an FX headwind of $0.02 compared to the prior year, which is a decrease from the prior guidance of the $0.03 headwind.
The updated guidance also includes EPS of $0.26 associated with the first nine months of 2024 tax benefits from stock-based compensation. Our guidance excludes future tax benefits from stock-based compensation.
I would now like to turn the call back over to Eric.
