- Wholly-Owned anti-PD-L1 and anti-CD166 Programs Entering Phase 2 Studies –

- Partnered Clinical Programs Advancing -

- Multiple Updates Anticipated Across Portfolio in 2020 -

SOUTH SAN FRANCISCO, Calif., Dec. 19, 2019 (GLOBE NEWSWIRE) -- CytomX Therapeutics, Inc. (Nasdaq: CTMX), a clinical-stage oncology-focused biopharmaceutical company pioneering a novel class of investigational antibody therapeutics based on its Probody™ therapeutic technology platform, today provided an update on its lead programs and 2020 clinical portfolio outlook.

“Our clinical pipeline today reflects the continued progress we have made in advancing our two wholly-owned lead programs, CX-072 and CX-2009, from initial clinical proof of concept into Phase 2 clinical development,” said Sean McCarthy, D. Phil., president, chief executive officer and chairman of CytomX Therapeutics. “Throughout 2019, we have also gained additional momentum in our partnered clinical programs. Bristol-Myers Squibb is advancing the anti-CTLA-4 probody, BMS-986249, into Phase 2 and the CytomX team continues Phase 1 dose escalation of CX-2029, an anti-CD71 probody drug conjugate, in partnership with AbbVie. All four of these clinical stage programs have the potential to make a meaningful difference for cancer patients and we look forward to providing updates in 2020.” 

PROCLAIM-CX-072 is a Phase 1/2 clinical program studying CX-072, an anti-PD-L1 Probody therapeutic in patients with solid tumors.

• In November 2019, the Company announced the initiation of a Simon 2 Stage Phase 2 clinical trial studying CX-072 in combination with YERVOY^® (ipilimumab) in relapsed or refractory melanoma. Stage 1 of this study aims to enroll up to 40 patients.
   
• The Phase 1 expansion arm of PROCLAIM-CX-072 studying CX-072 as monotherapy in selected tumor types, has completed enrollment. Data presented at the 2019 Annual Meeting of the American Society of Clinical Oncology confirmed evidence of clinical activity in several cancer types including triple negative breast cancer, squamous cell carcinoma and cutaneous squamous cell carcinoma with an encouraging safety profile. At this time, CytomX plans to focus further clinical development within this program on combinations with CX-072, including the ongoing Phase 2 study with ipilimumab.

PROCLAIM-CX-2009 is a Phase 1/2 clinical program studying CX-2009, an anti-CD166 Probody drug conjugate, as monotherapy for the treatment of solid tumors.

• The Phase 1 dose escalation and refinement stages of this trial are complete. Data reported at the 2019 Annual Meeting of the American Association of Cancer Research from the Phase 1 dose escalation trial showed encouraging anti-cancer activity and tolerability in several tumor types, including breast cancer, ovarian cancer and head and neck cancer. Based on these results, CytomX is initiating a Phase 2 expansion study of CX-2009 monotherapy at 7 mg/kg administered every three weeks in up to 40 patients with hormone receptor (ER, PR) positive, HER2 negative breast cancer.

“We continue to see forward progress across our wholly-owned and partnered clinical programs, affirming that CytomX’s Probody platform can potentially lead to innovative therapies that improve patient outcomes,” said Amy Peterson, M.D., chief development officer of CytomX Therapeutics.

2020 Clinical Outlook Across The CytomX Portfolio

PROCLAIM-CX-072

• Presentation of final data is anticipated from the expansion arms of the Phase 1/2 trial of CX-072 as monotherapy in multiple selected tumor types.
• Initial data is anticipated from the first stage of the ongoing Phase 2 trial of CX-072 in combination with ipilimumab in relapsed or refractory melanoma.

PROCLAIM-CX-2009

• Updated data is anticipated from the CX-2009 Phase 1 dose escalation and dose ranging studies.
• Enrollment of the Phase 2 expansion study of CX-2009 in hormone receptor (ER, PR) positive, HER2 negative breast cancer is anticipated throughout 2020.

PROCLAIM-CX-2029, an anti-CD71 Probody Drug Conjugate

• CytomX and its partner, AbbVie, anticipate the presentation of initial data from the Phase 1 dose escalation portion of the PROCLAIM-CX-2029 Phase 1/2 study.

BMS-986249, an anti-CTLA-4 Probody Therapeutic

• CytomX’s partner, Bristol-Myers Squibb (BMS), anticipates presenting data from the completed Phase 1 portion of the Phase 1/2a study evaluating BMS-986249 alone and in combination with OPDIVO^® (nivolumab) in advanced solid tumors.
• BMS is initiating the Phase 2 portion of this clinical trial, upon which CytomX is entitled to a $10 million milestone payment. 

About CytomX Therapeutics

CytomX Therapeutics is a clinical-stage oncology-focused biopharmaceutical company pioneering a novel class of investigational antibody therapeutics based on its Probody therapeutic technology platform. Probody therapeutics are designed to exploit unique conditions of the tumor microenvironment to more effectively localize antibody binding and activity while minimizing activity in healthy tissues. CytomX and its partners have four programs in the clinic. The Company’s clinical stage pipeline includes cancer immunotherapies against clinically validated targets, including a PD-L1-targeting Probody therapeutic wholly owned by CytomX (CX-072) and a CTLA-4-targeting Probody therapeutic partnered with Bristol Myers Squibb (BMS-986249). The CytomX clinical stage pipeline also includes first-in-class Probody drug conjugates against highly attractive targets, including a CD166-targeting Probody drug conjugate wholly owned by CytomX (CX-2009), and a CD71-targeting Probody drug conjugate partnered with AbbVie (CX-2029). CD166 and CD71 are among cancer targets that are considered to be inaccessible to conventional antibody drug conjugates due to their presence on many healthy tissues. In addition to its wholly owned programs, CytomX has strategic collaborations with AbbVie, Amgen, Bristol-Myers Squibb Company and ImmunoGen, Inc. For more information, visit www.cytomx.com.

CytomX Therapeutics Forward-Looking Statements

This press release includes forward-looking statements. Such forward-looking statements involve known and unknown risks, uncertainties and other important factors that are difficult to predict, may be beyond our control, and may cause the actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied in such statements. In particular, clinical data referenced above for CX-072 and CX-2009, including data on efficacy and safety, is based on a limited dataset and a limited number of patients and at specific doses and, in some cases, specific cancer types. Accordingly, you should not rely on any of these forward-looking statements, including those relating to the potential benefits, safety and efficacy of CX-072 or CX-2009, administered separately or in combination, the potential benefits or applications of CytomX’s Probody platform technology, CytomX’s ability to develop and advance product candidates into and successfully complete clinical trials, including the ongoing clinical trials of CX-072 and CX-2009, and the timing of any future clinical trials to be initiated by CytomX or its collaborative partners or the timing of the receipt or publication of the clinical data from any of the clinical trials. Risks and uncertainties that contribute to the uncertain nature of the forward-looking statements include: the unproven nature of CytomX’s novel Probody Platform technology; four of CytomX’s product candidates under its Probody platform are in the initial stages of clinical development and its other product candidates are currently in preclinical development, and the process by which preclinical and clinical development could potentially lead to an approved product is long and subject to significant risks and uncertainties; the possibility that the results of early clinical trials may not be predictive of future results; the possibility that CytomX’s clinical trials will not be successful; CytomX’s dependence on the success of CX-072, CX-2009, CX-2029 and BMS-986249; CytomX’s reliance on third parties for the manufacture of the company’s product candidates; and possible regulatory developments in the United States and foreign countries. Additional applicable risks and uncertainties include those relating to our preclinical research and development, clinical development, and other risks identified under the heading "Risk Factors" included in CytomX’s Quarterly Report on Form 10-Q filed with the SEC on November 7, 2019. The forward-looking statements contained in this press release are based on information currently available to CytomX and speak only as of the date on which they are made. CytomX does not undertake and specifically disclaims any obligation to update any forward-looking statements, whether as a result of any new information, future events, changed circumstances or otherwise.

PROBODY is a registered trademark of CytomX Therapeutics.
YERVOY and OPDIVO are registered trademarks of Bristol-Myers Squibb.

Contact:

Investors and Media:

Christopher Keenan
VP, Investor Relations and Corporate Communications
ckeenan@cytomx.com
650-383-0823

Source: CytomX Therapeutics Inc.