Filed Pursuant to Rule 425
Under the Securities Act of 1933
and Deemed Filed Pursuant to Rule 14a-12
Under the Securities Exchange Act of 1934
Subject Company: Enzon Pharmaceuticals, Inc.
NPS Pharmaceuticals, Inc.
Commission File No. 000-12957

The following materials were distributed by Enzon Pharmaceuticals, Inc. (“Enzon”) and NPS Pharmaceuticals, Inc. (“NPS”) to attendees of the 6 th  Annual Lehman Brothers’ Global Healthcare Investment Conference held in Miami Beach, Florida on March 5, 2003 to discuss the proposed business combination between Enzon and NPS.

 	Safe Harbor

Cautionary Statement For The Purpose Of The “Safe Harbor” Provisions
Of The Private Securities Litigation Reform Act Of 1995

This presentation contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These statements are based on management’s current expectations and beliefs and are subject to a number of factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. The forward-looking statements contained in this presentation include statements about future financial and operating results and the proposed NPS/Enzon merger. These statements are not guarantees of future performance, involve certain risks, uncertainties and assumptions that are difficult to predict, and are based upon assumptions as to future events that may not prove accurate. Therefore, actual outcomes and results may differ materially from what is expressed herein. For example, if either of the companies do not receive required stockholder or governmental approvals or fail to satisfy other conditions to closing, the transaction will not be consummated. In any forward-looking statement in which NPS or Enzon expresses an expectation or belief as to future results, such expectation or belief is expressed in good faith and believed to have a reasonable basis, but there can be no assurance that the statement or expectation or belief will result or be achieved or accomplished. The following factors, among others, could cause actual results to differ materially from those described in the forward-looking statements: the risk that the NPS and Enzon businesses will not be integrated successfully; costs related to the proposed merger, failure of the NPS or Enzon stockholders to approve the proposed merger; and other economic, business, competitive and/or regulatory factors affecting NPS’ and Enzon’s businesses generally as set forth in NPS’s and Enzon’s filings with the SEC, including their Annual Reports on Form 10-K for their respective most recent fiscal years, especially in the Management’s Discussion and Analysis section, their most recent Quarterly Reports on Form 10-Q and their Current Reports on Form 8-K. NPS and Enzon are under no obligation to (and expressly disclaim any such obligation to) update or alter their forward-looking statements whether as a result of new information, future events or otherwise.

 	

 	Additional Information And Where To Find It

In connection with the proposed NPS/Enzon merger, NPS, Enzon and Momentum Merger Corporation (which will be renamed by NPS and Enzon in connection with the proposed merger) intend to file a joint proxy statement/prospectus with the Securities and Exchange Commission (the “SEC”) in connection with the transaction described herein. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS WHEN IT BECOMES AVAILABLE BECAUSE IT WILL CONTAIN IMPORTANT INFORMATION ABOUT THE TRANSACTION DESCRIBED HEREIN. Investors and security holders may obtain a free copy of the joint proxy statement/prospectus (when it is available) and other documents filed by NPS and Enzon with the SEC at the SEC’s web site at www.sec.gov  or by contacting NPS at 801-583-4939 and through NPS’s website at www.npsp.com , or by contacting Enzon at 908-541-8678 and through Enzon’s website at www.enzon.com.

NPS and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the stockholders of NPS and Enzon in connection with the transaction described herein. Information regarding the special interests of these directors and executive officers in the transaction described herein will be included in the joint proxy statement/prospectus described above. Additional information regarding these directors and executive officers is also included in NPS’ proxy statement for its 2002 Annual Meeting of Stockholders, which was filed with the SEC on or about April 19, 2002. This document is available free of charge at the SEC’s web site at www.sec.gov or by contacting NPS at 801-583-4939 and through NPS’ website at [ www.npsp.com ]

Enzon and its directors and executive officers also may be deemed to be participants in the solicitation of proxies from the stockholders of Enzon and NPS in connection with the transaction described herein. Information regarding the special interests of these directors and executive officers in the transaction described herein will be included in the joint proxy statement/prospectus described above. Additional information regarding these directors and executive officers is also included in Enzon’s proxy statement for its 2002 Annual Meeting of Stockholders, which was filed with the SEC on or about October 28, 2002. This document is available free of charge at the SEC’s web site at www.sec.gov or by contacting Enzon at 908-541-8678.

Our Mutual Goal	

 	 	To Build a Sustainable Top-Tier Biotech

 	 	•	A deep, diversified & sustainable pipeline

 	 	•	A clearly defined pathway to profitability

 	 	•	A fully integrated infrastructure and stable financial position

 	 	 	 	 	

 	

Synergies Expand and Accelerate
Value Creation

	
 	•	Expand pipeline development
— e.g., CNS product opportunities

 	•	Accelerate program development
— e.g., ALX-0600 for multiple indications

 	•	Financial strength + commercial
capacity = maximize strategic
opportunities
— In-license products and technologies
— Optimize PREOS partnership

 	

Transaction Specifics

	
 	•	Summary:	
 	 	 	Stock for stock exchange

 	 	 	Timing: Joint proxy filed in March
             Expected shareholder vote in June*

 	 	 	Bankers:
• NPS: Morgan Stanley
• Enzon: SG Cowen

 	 	 	Exchange ratio calculated on approximately a 3 month Enzon trailing average

 	•	New Company Structure:

 	 	 	Hunter Jackson, Executive Chairman of the Board

 	 	 	Arthur Higgins, Chief Executive Officer

 	 	 	Board Split: 6 from NPS, 4 from Enzon

 	 	 	Management drawn from both companies  

*Subject to stockholder and regulatory approvals and other customary closing conditions

 	

 	

The Merger Creates a Top-Tier Biotech

	
 	•	Management with a proven track record of
building businesses

 	•	Strong, dependable revenues

 	•	Commercial infrastructure

 	•	Drug discovery and development expertise

 	•	Manufacturing capacity and expertise

 	

Post Merger Strengths

	
 	•	Fully Integrated:

 	 	 	From drug discovery through manufacturing and commercialization

 	•	Innovative and Robust Pipeline:

 	 	 	~$150M R&D Budget *

 	 	 	Phase III: 2 Programs

 	 	 	Phase II: 3 Programs

 	 	 	>10 early stage programs

 	 	 	Multiple Platform Technologies
	
 	 	 	* Based upon 2003 pro-forma financials

 	

Post Merger Strengths

	
 	•	Solid financial infrastructure:*

 	 	 	Revenue of ~$200M from 5 marketed products

 	 	 	>$300 million cash (at closing)

 	 	 	Solid cash flow

 	•	Significant partnerships validate R&D strengths:

 	 	 	Amgen

	Janssen

	Nektar

 	 	 	AstraZeneca

	Kirin

	SkyePharma

 	 	 	GSK

	Schering-
Plough

	MicroMet
	
 	 	 	* Based upon 2003 pro-forma financials

 	

 	

PEG-INTRON: L-T Growth Driver

	

 	•	HCV—an under-treated epidemic

 	 	 	Est. 4 Million U.S./4 Million EU

 	•	Re-treatment patients

 	 	 	~200,000 patients

 	•	Maintenance therapy

 	 	 	CO-PILOT study ongoing

 	•	Geographic & indication expansion

 	 	 	Japan — Est. 2 million infected

 	 	 	Oncology/HIV

 	

Product Pipeline & Marketed Products

 	 	Stage of Development	 	 	 	

	 	 	 	
 	
Product	  Preclinical/
  Research	Phase I	Phase II	Phase III	Marketed  	 	Indication(s)	Partner	

	
 	PEG-INTRON
	 	 	Hepatitis C	Schering-Plough	
 	ABELCET
	 	 	Antifungal	Proprietary	
 	ADAGEN
	 	 	SCIDS	Proprietary	
 	ONCASPAR	 	 	ALL/Leukemia
	Proprietary	
 	DEPOCYT
	 	 	Lymphomatous Meningitis	Proprietary	
 	Cinacalcet HCl
	 	 	 	Secondary HPT	Amgen/Kirin	
 	PREOS
	 	 	 	Osteoporosis	Proprietary	
 	PROTHECAN
	 	 	 	Various cancers	Proprietary	
 	ALX-0600
	 	 	 	GI Disorders	Proprietary	
 	Cinacalcet HCl
	 	 	 	Primary HPT	Amgen/Kirin	
 	NPS 1776
	 	 	 	Epilepsy / Migraine	Proprietary	
 	NPS 1506
	 	 	 	Acute Depression	Proprietary	
 	Calcilytics
	 	 	 	Osteoporosis	GSK	
 	PEG-Cytotoxics
	 	 	 	Various tumors	Proprietary	
 	Glycine Re-Uptake Inhibitors
	 	 	 	Schizophrenia and Dementia	Janssen	
 	Metabotropic Glutamate
Receptors
	 	 	 	Neurological disorders	AstraZeneca	
 	SCA’s
	 	 	 	Immunology	Micromet	
 	Inhaled Leuprolide
	 	 	 	Cancer	Nektar	
 	 	 	 	 	 	 	 	 	 	
 	 	 	= Enzon 	 	= NPS	 	 	 	 	

5 Marketed Products

	
 	•	PEG-INTRON ®

 	
 	•	ABELCET ®
	 	
 	•	ONCASPAR ®
	 	
 	•	DEPOCYT ®
	 	
 	•	ADAGEN ®

 	
 	•	Amphotericin B lipid complex with reduced nephrotoxicity

 	•	Amphotericin B has the broadest spectrum of activity of any antifungal agent

 	•	ABELCET is the market leader and Amphotericin B lipid formulation of choice

 	•	ABELCET is the most efficacious lipid formulation

 	•	Focused marketing and medical effort

 	•	Evaluate new treatment paradigms

 	

Additional Marketed Products

	
 	•	ONCASPAR (Pegylated Asparaginase)

 	 	 	Indicated for acute lymphoblastic leukemia

 	 	 	Stable sales growth

 	•	DEPOCYT (Cytarabine liposome injection)

 	 	 	Treatment of neoplastic meningitis

 	 	 	Significant growth potential

 	•	ADAGEN (Pegylated bovine ADA)

 	 	 	ADA deficient SCIDS (Bubble Boy Disease)

 	 	 	Lifetime therapy for limited population

 	

2 Phase III Clinical Products

	

 	
 	•	PREOS™
	 	
 	•	Cinacalcet HCl

 	 	

 	

PREOS (Intact Human Parathyroid Hormone)

	
 	•	Stimulates natural bone growth, with potential for:

 	
 	 	 	Stronger, healthier bones

 	 	 	A lower risk of fracture

 	•	Strong Phase II results:

 	 	 	12 month BMD increases up to 7%

 	 	 	No serious AEs at any dose

 	•	Recent PaTH data supports Phase II results and possible PREOS and alendronate combination	 	

 	 	

PREOS

	
 	•	Pivotal Phase III study to be completed in September 2003

 	•	FDA submission targeted for mid-2004

 	•	Current launch anticipated by late 2005

 	•	Expect to compete in a large and growing market

 	•	Combination offers the ability to more aggressively execute development program and negotiate an optimal partnership

	

Cinacalcet HCl for HPT

	
 	Market opportunity (U.S.)

 	
 	 	Primary HPT 500,000 patients

 	 	Secondary HPT 260,000 dialysis patients

 	 	Secondary HPT
800,000 predialysis patients

 	 	No specific pharmaceutical therapies - calcimimetics are first in class

	 	

Cinacalcet HCl

	
 	•	Phase III program on-going by Amgen

 	•	Amgen confirms 2H 03 NDA filing

 	•	First-in-class molecule in growing market

 	•	Potential for significant royalty stream

	

Product Pipeline & Marketed Products

 	 	Stage of Development	 	 	 	

	 	 	 	
 	
Product	Preclinical/
Research	Phase I	    Phase II	Phase III	Marketed 	 	Indication(s)	Partner	

	
 	PEG-INTRON
	 	 	Hepatitis C	Schering-Plough	
 	ABELCET
	 	 	Antifungal	Proprietary	
 	ADAGEN
	 	 	SCIDS	Proprietary	
 	ONCASPAR	 	 	ALL/Leukemia
	Proprietary	
 	DEPOCYT
	 	 	Lymphomatous Meningitis	Proprietary	
 	Cinacalcet HCl
	 	 	 	Secondary HPT	Amgen/Kirin	
 	PREOS
	 	 	 	Osteoporosis	Proprietary	
 	PROTHECAN
	 	 	 	Various cancers	Proprietary	
 	ALX-0600
	 	 	 	GI Disorders	Proprietary	
 	Cinacalcet HCl
	 	 	 	Primary HPT	Amgen/Kirin	
 	NPS 1776
	 	 	 	Epilepsy / Migraine	Proprietary	
 	NPS 1506
	 	 	 	Acute Depression	Proprietary	
 	Calcilytics
	 	 	 	Osteoporosis	GSK	
 	PEG-Cytotoxics
	 	 	 	Various tumors	Proprietary	
 	Glycine Re-Uptake Inhibitors
	 	 	 	Schizophrenia and Dementia	Janssen	
 	Metabotropic Glutamate
Receptors
	 	 	 	Neurological disorders	AstraZeneca	
 	SCA’s
	 	 	 	Immunology	Micromet	
 	Inhaled Leuprolide
	 	 	 	Cancer	Nektar	
 	 	 	 	 	 	 	 	 	 	
 	 	 	= Enzon	 	= NPS	 	 	 	 	

 	

Combined Management Team Includes:

	
 	•	Hunter Jackson, Ph.D. (NPS)	
 	 	 	•	Executive Chairman of the Board
	
 	•	Arthur J. Higgins (Enzon)	
 	 	 	•	Chief Executive Officer
	
 	•	Ulrich Grau, Ph.D. (Enzon)	
 	 	 	•	Chief Scientific Officer
	
 	•	Kenneth J. Zuerblis (Enzon)	
 	 	 	•	Vice President, Finance, Chief Financial Officer & Secretary
	
 	•	Thomas B. Marriott, Ph.D. (NPS)	
 	 	 	•	Vice President Development Research
	
 	•	Alan Mueller, Ph.D. (NPS)	
 	 	 	 	• Vice President Discovery Research

 	

 	

Selected Pro-Forma Financials

	
 	Pro-Forma Operating Summary	(US$ in millions)	 	
 	 	 	 	 	 	
 	Year Ending December 31,	Pro Forma 2002	 	

	 	
 	Product Revenues:	 	 	 	 	
 	      Sales	 	$	31.5	 	
 	      Royalties	 	$	82.6	 	

	 	
 	 	 	$	114.1	 	
 	 	 	 	 	 	
 	Expenses:	 	 	 	 	
 	      SG&A	 	$	48.0	 	
 	      R&D	 	$	102.0	 	
 	 	 	 	 	 	
 	Long-Term Convertible Debt	 	$	400.0	 	
 	Ending Cash Balance

	 	$	380.0	 	

Expected Milestones and News Flow

 	 	 	  = NPS	  	  = Enzon	 	 	 	 	 	 	
 	 	 	 	 	 	 	 	 	 	
 	Type	        2003	 	2004	 	2005	 	 	 	 	
 	 	 	 	 	 	 	 	 	
 	Clinical Data	Phase III Cinacalcet HCl data in secondary HPT	 	 	 	 	 	
 	Regulatory	File Cinacalcet NDA	 	 	 	 	 	
 	Clinical Data	PREOS 2-year rat toxicology study data	 	 	 	 	 	
 	Clinical Data	PREOS Top Study completed	 	 	 	 	 	
 	Clinical Data	Phase IIa results from PROTHECAN	 	 	 	 	 	
 	Clinical Data	Initiate additional PII/III ALX-0600 (SBS)	 	 	 	 	 	
 	Market Data	 	Results from HCV maintenance studies (Co-PILOT, PEG-Intron; HALT-C, Pegasys)	 	 	
 	Regulatory	 	 	File PREOS NDA	 	 	
 	Regulatory	 	 	Initiate Prothecan Phase III clinical program	 	 	
 	Clinical Data	 	 	Phase III PREOS POWER study data	 	 	
 	Clinical Data	 	 	Phase III PREOS TOP study data (full 18 months)	 	 	
 	Regulatory	 	 	 	Cinacalcet HCl approval & launch in the U.S. and Europe	 	 	
 	Regulatory	 	 	 	 	File IND for two SCA Projects	 	 	
 	Regulatory	 	 	 	 	File IND on inhaled Leuprolide (Nektar) for cancer	 	 	
 	Regulatory	 	 	 	 	 	PREOS approval in U.S	 	 	

	 	 	

 	 	 	 	 	 	 	 	 	 	

Synergies Expand and Accelerate
Value Creation

	
 	•	Expand pipeline development
— e.g., CNS product opportunities

 	•	Accelerate program development
— e.g., ALX-0600 for multiple indications

 	•	Financial strength + commercial
capacity = maximize strategic
opportunities
— In-license products and technologies
— Optimize PREOS partnership

 	

2007… Where We’re Going

	
 	•	Top-tier biotechnology company

 	•	Strong, balanced clinical pipeline

 	•	Revenue > $500M

 	•	R&D budget > $180M

 	•	EBITDA > $100M

 	•	Industry leading growth rate

 	•	Cash > $500M